1.2: Themes and Concepts of Biology - Biology

1.2: Themes and Concepts of Biology - Biology

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Skills to Develop

  • Identify and describe the properties of life
  • Describe the levels of organization among living things
  • Recognize and interpret a phylogenetic tree
  • List examples of different sub disciplines in biology

Biology is the science that studies life, but what exactly is life? This may sound like a silly question with an obvious response, but it is not always easy to define life. For example, a branch of biology called virology studies viruses, which exhibit some of the characteristics of living entities but lack others. It turns out that although viruses can attack living organisms, cause diseases, and even reproduce, they do not meet the criteria that biologists use to define life. Consequently, virologists are not biologists, strictly speaking. Similarly, some biologists study the early molecular evolution that gave rise to life; since the events that preceded life are not biological events, these scientists are also excluded from biology in the strict sense of the term.

From its earliest beginnings, biology has wrestled with three questions: What are the shared properties that make something “alive”? And once we know something is alive, how do we find meaningful levels of organization in its structure? And, finally, when faced with the remarkable diversity of life, how do we organize the different kinds of organisms so that we can better understand them? As new organisms are discovered every day, biologists continue to seek answers to these and other questions.

Properties of Life

All living organisms share several key characteristics or functions: order, sensitivity or response to the environment, reproduction, adaptation, growth and development, regulation, homeostasis, energy processing, and evolution. When viewed together, these nine characteristics serve to define life.


Organisms are highly organized, coordinated structures that consist of one or more cells. Even very simple, single-celled organisms are remarkably complex: inside each cell, atoms make up molecules; these in turn make up cell organelles and other cellular inclusions. In multicellular organisms (Figure (PageIndex{1})), similar cells form tissues. Tissues, in turn, collaborate to create organs (body structures with a distinct function). Organs work together to form organ systems.

Sensitivity or Response to Stimuli

Organisms respond to diverse stimuli. For example, plants can bend toward a source of light, climb on fences and walls, or respond to touch (Figure (PageIndex{2})). Even tiny bacteria can move toward or away from chemicals (a process called chemotaxis) or light (phototaxis). Movement toward a stimulus is considered a positive response, while movement away from a stimulus is considered a negative response.

Video: Watch this video to see how plants respond to a stimulus—from opening to light, to wrapping a tendril around a branch, to capturing prey.


Single-celled organisms reproduce by first duplicating their DNA, and then dividing it equally as the cell prepares to divide to form two new cells. Multicellular organisms often produce specialized reproductive germline cells that will form new individuals. When reproduction occurs, genes containing DNA are passed along to an organism’s offspring. These genes ensure that the offspring will belong to the same species and will have similar characteristics, such as size and shape.

Growth and Development

Organisms grow and develop following specific instructions coded for by their genes. These genes provide instructions that will direct cellular growth and development, ensuring that a species’ young (Figure (PageIndex{3})) will grow up to exhibit many of the same characteristics as its parents.


Even the smallest organisms are complex and require multiple regulatory mechanisms to coordinate internal functions, respond to stimuli, and cope with environmental stresses. Two examples of internal functions regulated in an organism are nutrient transport and blood flow. Organs (groups of tissues working together) perform specific functions, such as carrying oxygen throughout the body, removing wastes, delivering nutrients to every cell, and cooling the body.


In order to function properly, cells need to have appropriate conditions such as proper temperature, pH, and appropriate concentration of diverse chemicals. These conditions may, however, change from one moment to the next. Organisms are able to maintain internal conditions within a narrow range almost constantly, despite environmental changes, through homeostasis (literally, “steady state”)—the ability of an organism to maintain constant internal conditions. For example, an organism needs to regulate body temperature through a process known as thermoregulation. Organisms that live in cold climates, such as the polar bear (Figure (PageIndex{4})), have body structures that help them withstand low temperatures and conserve body heat. Structures that aid in this type of insulation include fur, feathers, blubber, and fat. In hot climates, organisms have methods (such as perspiration in humans or panting in dogs) that help them to shed excess body heat.

Energy Processing

All organisms use a source of energy for their metabolic activities. Some organisms capture energy from the sun and convert it into chemical energy in food; others use chemical energy in molecules they take in as food (Figure (PageIndex{5})).

Levels of Organization of Living Things

Living things are highly organized and structured, following a hierarchy that can be examined on a scale from small to large. The atom is the smallest and most fundamental unit of matter. It consists of a nucleus surrounded by electrons. Atoms form molecules. A molecule is a chemical structure consisting of at least two atoms held together by one or more chemical bonds. Many molecules that are biologically important are macromolecules, large molecules that are typically formed by polymerization (a polymer is a large molecule that is made by combining smaller units called monomers, which are simpler than macromolecules). An example of a macromolecule is deoxyribonucleic acid (DNA) (Figure (PageIndex{6})), which contains the instructions for the structure and functioning of all living organisms.

Video: Watch this video that animates the three-dimensional structure of the DNA molecule shown in [link].

Some cells contain aggregates of macromolecules surrounded by membranes; these are called organelles. Organelles are small structures that exist within cells. Examples of organelles include mitochondria and chloroplasts, which carry out indispensable functions: mitochondria produce energy to power the cell, while chloroplasts enable green plants to utilize the energy in sunlight to make sugars. All living things are made of cells; the cell itself is the smallest fundamental unit of structure and function in living organisms. (This requirement is why viruses are not considered living: they are not made of cells. To make new viruses, they have to invade and hijack the reproductive mechanism of a living cell; only then can they obtain the materials they need to reproduce.) Some organisms consist of a single cell and others are multicellular. Cells are classified as prokaryotic or eukaryotic. Prokaryotes are single-celled or colonial organisms that do not have membrane-bound nuclei; in contrast, the cells of eukaryotes do have membrane-bound organelles and a membrane-bound nucleus.

In larger organisms, cells combine to make tissues, which are groups of similar cells carrying out similar or related functions. Organs are collections of tissues grouped together performing a common function. Organs are present not only in animals but also in plants. An organ system is a higher level of organization that consists of functionally related organs. Mammals have many organ systems. For instance, the circulatory system transports blood through the body and to and from the lungs; it includes organs such as the heart and blood vessels. Organisms are individual living entities. For example, each tree in a forest is an organism. Single-celled prokaryotes and single-celled eukaryotes are also considered organisms and are typically referred to as microorganisms.

All the individuals of a species living within a specific area are collectively called a population. For example, a forest may include many pine trees. All of these pine trees represent the population of pine trees in this forest. Different populations may live in the same specific area. For example, the forest with the pine trees includes populations of flowering plants and also insects and microbial populations. A community is the sum of populations inhabiting a particular area. For instance, all of the trees, flowers, insects, and other populations in a forest form the forest’s community. The forest itself is an ecosystem. An ecosystem consists of all the living things in a particular area together with the abiotic, non-living parts of that environment such as nitrogen in the soil or rain water. At the highest level of organization (Figure (PageIndex{7})), the biosphere is the collection of all ecosystems, and it represents the zones of life on earth. It includes land, water, and even the atmosphere to a certain extent.

Art Connection

Figure (PageIndex{7}): The biological levels of organization of living things are shown. From a single organelle to the entire biosphere, living organisms are parts of a highly structured hierarchy. (credit “organelles”: modification of work by Umberto Salvagnin; credit “cells”: modification of work by Bruce Wetzel, Harry Schaefer/ National Cancer Institute; credit “tissues”: modification of work by Kilbad; Fama Clamosa; Mikael Häggström; credit “organs”: modification of work by Mariana Ruiz Villareal; credit “organisms”: modification of work by "Crystal"/Flickr; credit “ecosystems”: modification of work by US Fish and Wildlife Service Headquarters; credit “biosphere”: modification of work by NASA)

Which of the following statements is false?

  • Tissues exist within organs which exist within organ systems.
  • Communities exist within populations which exist within ecosystems.
  • Organelles exist within cells which exist within tissues.
  • Communities exist within ecosystems which exist in the biosphere.

The Diversity of Life

The fact that biology, as a science, has such a broad scope has to do with the tremendous diversity of life on earth. The source of this diversity is evolution, the process of gradual change during which new species arise from older species. Evolutionary biologists study the evolution of living things in everything from the microscopic world to ecosystems.

The evolution of various life forms on Earth can be summarized in a phylogenetic tree (Figure (PageIndex{8})). A phylogenetic tree is a diagram showing the evolutionary relationships among biological species based on similarities and differences in genetic or physical traits or both. A phylogenetic tree is composed of nodes and branches. The internal nodes represent ancestors and are points in evolution when, based on scientific evidence, an ancestor is thought to have diverged to form two new species. The length of each branch is proportional to the time elapsed since the split.

Evolution Connection

Carl Woese and the Phylogenetic TreeIn the past, biologists grouped living organisms into five kingdoms: animals, plants, fungi, protists, and bacteria. The organizational scheme was based mainly on physical features, as opposed to physiology, biochemistry, or molecular biology, all of which are used by modern systematics. The pioneering work of American microbiologist Carl Woese in the early 1970s has shown, however, that life on Earth has evolved along three lineages, now called domains—Bacteria, Archaea, and Eukarya. The first two are prokaryotic cells with microbes that lack membrane-enclosed nuclei and organelles. The third domain contains the eukaryotes and includes unicellular microorganisms together with the four original kingdoms (excluding bacteria). Woese defined Archaea as a new domain, and this resulted in a new taxonomic tree (Figure 1.2.8). Many organisms belonging to the Archaea domain live under extreme conditions and are called extremophiles. To construct his tree, Woese used genetic relationships rather than similarities based on morphology (shape).

Woese’s tree was constructed from comparative sequencing of the genes that are universally distributed, present in every organism, and conserved (meaning that these genes have remained essentially unchanged throughout evolution). Woese’s approach was revolutionary because comparisons of physical features are insufficient to differentiate between the prokaryotes that appear fairly similar in spite of their tremendous biochemical diversity and genetic variability (Figure (PageIndex{9})). The comparison of homologous DNA and RNA sequences provided Woese with a sensitive device that revealed the extensive variability of prokaryotes, and which justified the separation of the prokaryotes into two domains: bacteria and archaea.

Branches of Biological Study

The scope of biology is broad and therefore contains many branches and subdisciplines. Biologists may pursue one of those subdisciplines and work in a more focused field. For instance, molecular biology and biochemistry study biological processes at the molecular and chemical level, including interactions among molecules such as DNA, RNA, and proteins, as well as the way they are regulated. Microbiology, the study of microorganisms, is the study of the structure and function of single-celled organisms. It is quite a broad branch itself, and depending on the subject of study, there are also microbial physiologists, ecologists, and geneticists, among others.

Career Connection

Forensic Scientist: Forensic science is the application of science to answer questions related to the law. Biologists as well as chemists and biochemists can be forensic scientists. Forensic scientists provide scientific evidence for use in courts, and their job involves examining trace materials associated with crimes. Interest in forensic science has increased in the last few years, possibly because of popular television shows that feature forensic scientists on the job. Also, the development of molecular techniques and the establishment of DNA databases have expanded the types of work that forensic scientists can do. Their job activities are primarily related to crimes against people such as murder, rape, and assault. Their work involves analyzing samples such as hair, blood, and other body fluids and also processing DNA (Figure (PageIndex{10})) found in many different environments and materials. Forensic scientists also analyze other biological evidence left at crime scenes, such as insect larvae or pollen grains. Students who want to pursue careers in forensic science will most likely be required to take chemistry and biology courses as well as some intensive math courses.

Another field of biological study, neurobiology, studies the biology of the nervous system, and although it is considered a branch of biology, it is also recognized as an interdisciplinary field of study known as neuroscience. Because of its interdisciplinary nature, this subdiscipline studies different functions of the nervous system using molecular, cellular, developmental, medical, and computational approaches.

Paleontology, another branch of biology, uses fossils to study life’s history (Figure (PageIndex{11})). Zoology and botany are the study of animals and plants, respectively. Biologists can also specialize as biotechnologists, ecologists, or physiologists, to name just a few areas. This is just a small sample of the many fields that biologists can pursue.

Biology is the culmination of the achievements of the natural sciences from their inception to today. Excitingly, it is the cradle of emerging sciences, such as the biology of brain activity, genetic engineering of custom organisms, and the biology of evolution that uses the laboratory tools of molecular biology to retrace the earliest stages of life on earth. A scan of news headlines—whether reporting on immunizations, a newly discovered species, sports doping, or a genetically-modified food—demonstrates the way biology is active in and important to our everyday world.


Biology is the science of life. All living organisms share several key properties such as order, sensitivity or response to stimuli, reproduction, growth and development, regulation, homeostasis, and energy processing. Living things are highly organized parts of a hierarchy that includes atoms, molecules, organelles, cells, tissues, organs, and organ systems. Organisms, in turn, are grouped as populations, communities, ecosystems, and the biosphere. The great diversity of life today evolved from less-diverse ancestral organisms over billions of years. A diagram called a phylogenetic tree can be used to show evolutionary relationships among organisms.

Biology is very broad and includes many branches and subdisciplines. Examples include molecular biology, microbiology, neurobiology, zoology, and botany, among others.

Art Connections

[link] Which of the following statements is false?

  1. Tissues exist within organs which exist within organ systems.
  2. Communities exist within populations which exist within ecosystems.
  3. Organelles exist within cells which exist within tissues.
  4. Communities exist within ecosystems which exist in the biosphere.

[link] Communities exist within populations which exist within ecosystems.

Review Questions

The smallest unit of biological structure that meets the functional requirements of “living” is the ________.

  1. organ
  2. organelle
  3. cell
  4. macromolecule


Viruses are not considered living because they ________.

  1. are not made of cells
  2. lack cell nuclei
  3. do not contain DNA or RNA
  4. cannot reproduce


The presence of a membrane-enclosed nucleus is a characteristic of ________.

  1. prokaryotic cells
  2. eukaryotic cells
  3. living organisms
  4. bacteria


A group of individuals of the same species living in the same area is called a(n) ________.

  1. family
  2. community
  3. population
  4. ecosystem


Which of the following sequences represents the hierarchy of biological organization from the most inclusive to the least complex level?

  1. organelle, tissue, biosphere, ecosystem, population
  2. organ, organism, tissue, organelle, molecule
  3. organism, community, biosphere, molecule, tissue, organ
  4. biosphere, ecosystem, community, population, organism


Where in a phylogenetic tree would you expect to find the organism that had evolved most recently?

  1. at the base
  2. within the branches
  3. at the nodes
  4. at the branch tips


Free Response

Select two items that biologists agree are necessary in order to consider an organism “alive.” For each, give an example of a non-living object that otherwise fits the definition of “alive,”

Answers will vary. Layers of sedimentary rock have order but are not alive. Technology is capable of regulation but is not, of itself, alive.

Consider the levels of organization of the biological world, and place each of these items in order from smallest level of organization to most encompassing: skin cell, elephant, water molecule, planet Earth, tropical rainforest, hydrogen atom, wolf pack, liver.

Smallest level of organization to largest: hydrogen atom, water molecule, skin cell, liver, elephant, wolf pack, tropical rainforest, planet Earth

You go for a long walk on a hot day. Give an example of a way in which homeostasis keeps your body healthy.

During your walk, you may begin to perspire, which cools your body and helps your body to maintain a constant internal temperature. You might also become thirsty and pause long enough for a cool drink, which will help to restore the water lost during perspiration.

Using examples, explain how biology can be studied from a microscopic approach to a global approach.

Researchers can approach biology from the smallest to the largest, and everything in between. For instance, an ecologist may study a population of individuals, the population’s community, the community’s ecosystem, and the ecosystem’s part in the biosphere. When studying an individual organism, a biologist could examine the cell and its organelles, the tissues that the cells make up, the organs and their respective organ systems, and the sum total—the organism itself.


smallest and most fundamental unit of matter
study of the chemistry of biological organisms
collection of all the ecosystems on Earth
study of plants
smallest fundamental unit of structure and function in living things
set of populations inhabiting a particular area
all the living things in a particular area together with the abiotic, nonliving parts of that environment
organism with cells that have nuclei and membrane-bound organelles
process of gradual change during which new species arise from older species and some species become extinct
ability of an organism to maintain constant internal conditions
large molecule, typically formed by the joining of smaller molecules
study of the structure and function of microorganisms
chemical structure consisting of at least two atoms held together by one or more chemical bonds
molecular biology
study of biological processes and their regulation at the molecular level, including interactions among molecules such as DNA, RNA, and proteins
study of the biology of the nervous system
collection of related tissues grouped together performing a common function
organ system
level of organization that consists of functionally related interacting organs
small structures that exist within cells and carry out cellular functions
individual living entity
study of life’s history by means of fossils
phylogenetic tree
diagram showing the evolutionary relationships among various biological species based on similarities and differences in genetic or physical traits or both; in essence, a hypothesis concerning evolutionary connections
all of the individuals of a species living within a specific area
single-celled organism that lacks organelles and does not have nuclei surrounded by a nuclear membrane
group of similar cells carrying out related functions
study of animals

1.2 Themes and Concepts of Biology

Biology is the science that studies life, but what exactly is life? This may sound like a silly question with an obvious response, but it is not always easy to define life. For example, a branch of biology called virology studies viruses, which exhibit some of the characteristics of living entities but lack others. It turns out that although viruses can attack living organisms, cause diseases, and even reproduce, they do not meet the criteria that biologists use to define life. Consequently, virologists are not biologists, strictly speaking. Similarly, some biologists study the early molecular evolution that gave rise to life since the events that preceded life are not biological events, these scientists are also excluded from biology in the strict sense of the term.

From its earliest beginnings, biology has wrestled with three questions: What are the shared properties that make something “alive”? And once we know something is alive, how do we find meaningful levels of organization in its structure? And, finally, when faced with the remarkable diversity of life, how do we organize the different kinds of organisms so that we can better understand them? As new organisms are discovered every day, biologists continue to seek answers to these and other questions.

Properties of Life

All groups of living organisms share several key characteristics or functions: order, sensitivity or response to stimuli, reproduction, adaptation, growth and development, regulation, homeostasis, and energy processing. When viewed together, these eight characteristics serve to define life.


Figure 1. A toad represents a highly organized structure consisting of cells, tissues, organs, and organ systems. (credit: “Ivengo(RUS)”/Wikimedia Commons)

Organisms are highly organized structures that consist of one or more cells. Even very simple, single-celled organisms are remarkably complex. Inside each cell, atoms make up molecules. These in turn make up cell components or organelles. Multicellular organisms, which may consist of millions of individual cells, have an advantage over single-celled organisms in that their cells can be specialized to perform specific functions, and even sacrificed in certain situations for the good of the organism as a whole. How these specialized cells come together to form organs such as the heart, lung, or skin in organisms like the toad shown in Figure 1 will be discussed later.

Sensitivity or Response to Stimuli

Organisms respond to diverse stimuli. For example, plants can grow toward a source of light or respond to touch (Figure 2). Even tiny bacteria can move toward or away from chemicals (a process called chemotaxis) or light (phototaxis). Movement toward a stimulus is considered a positive response, while movement away from a stimulus is considered a negative response.

Figure 2. The leaves of this sensitive plant (Mimosa pudica) will instantly droop and fold when touched. After a few minutes, the plant returns to its normal state. (credit: Alex Lomas)

Concept in Action

Watch this short 13 second video to see how the sensitive plant responds to a touch stimulus.


Single-celled organisms reproduce by first duplicating their DNA, which is the genetic material, and then dividing it equally as the cell prepares to divide to form two new cells. Many multicellular organisms (those made up of more than one cell) produce specialized reproductive cells that will form new individuals. When reproduction occurs, DNA containing genes is passed along to an organism’s offspring. These genes are the reason that the offspring will belong to the same species and will have characteristics similar to the parent, such as fur color and blood type.


All living organisms exhibit a “fit” to their environment. Biologists refer to this fit as adaptation and it is a consequence of evolution by natural selection, which operates in every lineage of reproducing organisms. Examples of adaptations are as diverse as unique heat-resistant Archaea that live in boiling hot springs to the tongue length of a nectar-feeding moth that matches the size of the flower from which it feeds. All adaptations enhance the reproductive potential of the individual exhibiting them, including their ability to survive to reproduce. Adaptations are not constant. As an environment changes, natural selection causes the characteristics of the individuals in a population to track those changes.

Growth and Development

Figure 3. Although no two look alike, these kittens have inherited genes from both parents and share many of the same characteristics. (credit: Pieter & Renée Lanser)

All organisms grow and develop according to specific instructions coded for by their genes. These genes provide instructions that will direct cellular growth and development, ensuring that a species’ young (Figure 3) will grow up to exhibit many of the same characteristics as its parents.


Even the smallest organisms are complex and require multiple regulatory mechanisms to coordinate internal functions, such as the transport of nutrients, response to stimuli, and coping with environmental stresses. For example, organ systems such as the digestive or circulatory systems perform specific functions like carrying oxygen throughout the body, removing wastes, delivering nutrients to every cell, and cooling the body.


Figure 4. Polar bears and other mammals living in ice-covered regions maintain their body temperature by generating heat and reducing heat loss through thick fur and a dense layer of fat under their skin. (credit: “longhorndave”/Flickr)

To function properly, cells require appropriate conditions such as proper temperature, pH, and concentrations of diverse chemicals. These conditions may, however, change from one moment to the next. Organisms are able to maintain internal conditions within a narrow range almost constantly, despite environmental changes, through a process called homeostasis or “steady state”—the ability of an organism to maintain constant internal conditions. For example, many organisms regulate their body temperature in a process known as thermoregulation. Organisms that live in cold climates, such as the polar bear (Figure 4), have body structures that help them withstand low temperatures and conserve body heat. In hot climates, organisms have methods (such as perspiration in humans or panting in dogs) that help them to shed excess body heat.

Energy Processing

All organisms (such as the California condor shown in Figure 5) use a source of energy for their metabolic activities. Some organisms capture energy from the Sun and convert it into chemical energy in food others use chemical energy from molecules they take in.

Figure 5. A lot of energy is required for a California condor to fly. Chemical energy derived from food is used to power flight. California condors are an endangered species scientists have strived to place a wing tag on each bird to help them identify and locate each individual bird. (credit: Pacific Southwest Region U.S. Fish and Wildlife)

Overview of the Biology Placement/Advisory Test

The Biology Placement/Advisory Test is a 60 minute test that contains 30 multiple-choice questions that cover central concepts in molecular biology, cell biology, genetics, and evolutionary biology. We recommend that all students that are considering taking Biology at Dartmouth complete this test. As the name suggests, the result of the Biology Placement/Advisory Test is advisory, not binding. Since there is no formal placement associated with the Biology Placement/Advisory Test, the score does not appear on your placement record in Banner Student. If you are interested in studying Biology at Dartmouth, we strongly suggest that you take the Biology Placement/Advisory Test to help you decide which Biology course is most appropriate for you to begin study of Biology at Dartmouth. In addition, the Biology Placement/Advisory Test is required for admission to Biology 19 (Honors Cell Structure and Function).

The Biology Placement/Advisory test can be accessed via the Canvas site at the following- link.

Chapter 1 – Exploring Life – Lecture Outline

1. High-throughput technology. Systems biology depends on methods that can analyze biological materials very quickly and produce enormous amounts of data. An example is the automatic DNA-sequencing machines used by the Human Genome Project.
2. Bioinformatics. The huge databases from high-throughput methods require computing power, software, and mathematical models to process and integrate information.
3. Interdisciplinary research teams. Systems biology teams may include engineers, medical scientists, physicists, chemists, mathematicians, and computer scientists as well as biologists.

  • Regulatory mechanisms ensure a dynamic balance in living systems.
  • Chemical processes within cells are accelerated, or catalyzed, by specialized protein molecules, called enzymes.
  • Each type of enzyme catalyzes a specific chemical reaction.
  • In many cases, reactions are linked into chemical pathways, each step with its own enzyme.
  • How does a cell coordinate its various chemical pathways?
  • Many biological processes are self-regulating: the output or product of a process regulates that very process.
  • In negative feedback, or feedback inhibition, accumulation of an end product of a process slows or stops that process.
  • Though less common, some biological processes are regulated by positive feedback, in which an end product speeds up its own production.
  • Feedback is common to life at all levels, from the molecular level to the biosphere.
  • Such regulation is an example of the integration that makes living systems much greater than the sum of their parts.

Concept 1.3 Biologists explore life across its great diversity of species

  • Biology can be viewed as having two dimensions: a “vertical” dimension covering the size scale from atoms to the biosphere and a “horizontal” dimension that stretches across the diversity of life.
  • The latter includes not only present-day organisms, but also those that have existed throughout life’s history.
  • Living things show diversity and unity.
  • Life is enormously diverse.
  • Biologists have identified and named about 1.8 million species.
  • This diversity includes 5,200 known species of prokaryotes, 100,000 fungi, 290,000 plants, 50,000 vertebrates, and 1,000,000 insects.
  • Thousands of newly identified species are added each year.
  • Estimates of the total species count range from 10 million to more than 200 million.
  • In the face of this complexity, humans are inclined to categorize diverse items into a smaller number of groups.
  • Taxonomy is the branch of biology that names and classifies species into a hierarchical order.
  • Until the past decade, biologists divided the diversity of life into five kingdoms.
  • New methods, including comparisons of DNA among organisms, have led to a reassessment of the number and boundaries of the kingdoms.
  • Various classification schemes now include six, eight, or even dozens of kingdoms.
  • Coming from this debate has been the recognition that there are three even higher levels of classifications, the domains.
  • the three domains are Bacteria, Archaea, and Eukarya.
  • The first two domains, domain Bacteria and domain Archaea, consist of prokaryotes.
  • All the eukaryotes are now grouped into various kingdoms of the domain Eukarya.
  • The recent taxonomic trend has been to split the single-celled eukaryotes and their close relatives into several kingdoms.
  • Domain Eukarya also includes the three kingdoms of multicellular eukaryotes: the kingdoms Plantae, Fungi, and Animalia.
  • These kingdoms are distinguished partly by their modes of nutrition.
  • Most plants produce their own sugars and food by photosynthesis.
  • Most fungi are decomposers that absorb nutrients by breaking down dead organisms and organic wastes.
  • Animals obtain food by ingesting other organisms.
  • Underlying the diversity of life is a striking unity, especially at the lower levels of organization.
  • The universal genetic language of DNA unites prokaryotes and eukaryotes.
  • Among eukaryotes, unity is evident in many details of cell structure.
  • Above the cellular level, organisms are variously adapted to their ways of life.
  • How do we account for life’s dual nature of unity and diversity?
  • The process of evolution explains both the similarities and differences among living things.

Concept 1.4 Evolution accounts for life’s unity and diversity

  • The history of life is a saga of a changing Earth billions of years old, inhabited by a changing cast of living forms.
  • Charles Darwin brought evolution into focus in 1859 when he presented two main concepts in one of the most important and controversial books ever written, On the Origin of Species by Natural Selection.
  • Darwin ’s first point was that contemporary species arose from a succession of ancestors through “descent with modification.”
  • This term captured the duality of life’s unity and diversity: unity in the kinship among species that descended from common ancestors and diversity in the modifications that evolved as species branched from their common ancestors.
  • Darwin ’s second point was his mechanism for descent with modification: natural selection.
  • Darwin inferred natural selection by connecting two observations:
  • Observation 1: Individual variation. Individuals in a population of any species vary in many heritable traits.
  • Observation 2: Overpopulation and competition. Any population can potentially produce far more offspring than the environment can support. This creates a struggle for existence among variant members of a population.
  • Inference: Unequal reproductive success. Darwin inferred that those individuals with traits best suited to the local environment would leave more healthy, fertile offspring.
  • Inference: Evolutionary adaptation. Unequal reproductive success can lead to adaptation of a population to its environment. Over generations, heritable traits that enhance survival and reproductive success will tend to increase in frequency among a population’s individuals. The population evolves.
  • Natural selection, by its cumulative effects over vast spans of time, can produce new species from ancestral species.
  • For example, a population fragmented into several isolated populations in different environments may gradually diversify into many species as each population adapts over many generations to different environmental problems.
  • Fourteen species of finches found on the Galápagos Islands diversified after an ancestral finch species reached the archipelago from the South American mainland.
  • Each species is adapted to exploit different food sources on different islands.
  • Biologists’ diagrams of evolutionary relationships generally take a treelike form.
  • Just as individuals have a family tree, each species is one twig of a branching tree of life.
  • Similar species like the Galápagos finches share a recent common ancestor.
  • Finches share a more distant ancestor with all other birds.
  • The common ancestor of all vertebrates is even more ancient.
  • Trace life back far enough, and there is a shared ancestor of all living things.
  • All of life is connected through its long evolutionary history.

Concept 1.5 Biologists use various forms of inquiry to explore life

Conceptual Learning in IB Biology

If you’re an IB Biology teacher here’s a challenge (or perhaps not):

  • List and describe the four basic biological concepts that run through the discipline of Biology.

Got it? Here they are (highlight to see):

  • Structure & Function
  • Universality versus Diversity
  • Equilibrium within Systems
  • Evolution

They are on page 40 on the subject guide.

Teachers in MYP schools will be well aware of the concept-based nature of the Next Chapter as it arrives, but in reality it may already be here in our classes. How many times do we ask students how the knowledge we have gathered in a lesson or sequence connects to other knowledge, looking for commonalities and themes? This, in a simple way, is teaching for conceptual understanding*. We want students to be able to recognise concepts in new content – the universal nature of the genetic code and the diversity it facilitates adaptations to maintain homeostasis (equilibrium) within living systems, the relationships we see between structure and function in all living systems and the process of evolution by natural selection that underpins them all.

I want to make it a personal goal this year to be more explicit in the learning of the big ideas of Biology: the concepts. We’ll start this week with a group task for students to try to connect these concepts to their latent understandings of Biology and we’ll build from there.

Some ideas for teaching the concepts in Biology:

  • Jigsaw tasks for students in different groups as we review a unit: one group for each concept who need to explain how the content of the unit feeds into that one conceptual understanding.
  • Connect-extend-challenge (a visible thinking routine**). As we build a body of biological knowledge students can reflect and review based on how this connects to each of the four concepts, how they might extend their understanding with deeper questions and what they have found challenging in the unit/ lesson.
  • Concept walls: spaces in different parts of the classroom where students might pin their thoughts on the topic (or post post-its).

If you have more ideas for how to use the concepts of biology to strengthen students’ understanding, please share!

Further Reading

* ‘Teaching the Disciplines – Nurturing big Ideas for Deeper Understanding’ is an excellent document from the MYP section of the OCC. Read the section on the sciences.

**Harvard’s Project Zero has a fantastic set of thinking routines to make thinking visible. Try them out!


Book Description

In this survey text, directed at those not majoring in biology, we dispel the assumption that a little learning is a dangerous thing. We hope that by skimming the surface of a very deep subject, biology, we may inspire you to drink more deeply and make more informed choices relating to your health, the environment, politics, and the greatest subject that are all of us are entwined in, life itself.

  • Unit 1: The Cellular Foundation of Life
  • Unit 2: Cell Division and Genetics
  • Unit 3: Molecular Biology and Biotechnology
  • Unit 4: Animal Structure and Function



Shared Flashcard Set

Complex organization formed from a simpler combination of parts.

Example: Your Body, An ecosystem ..such as a forest is also a biological system. Like your body, an ecosystem has properties that depend on how its parts interact.

organism that obtains food by eating producers (autotrophs) or other consumers (Concepts 1.3, 7.1, 36.1)



Inherited characteristic that improves an organism's ability to survive and reproduce in a particular environment (Concepts 1.3, 14.1)

Group of individuals of the same species living in a particular area at the same time

Natural Selection:

Process by which individuals with inherited characteristics well-suited to the environment leave more offspring than do other individuals

Generation-to-generation change in the proportion of different inherited genes in a population that account for all of the changes that have transformed life over an immense time

Cell lacking a nucleus and most other organelles

Bacteria and Archaea are made of Prokaryotic

Cell with a nucleus (surrounded by its own membrane) and other internal organelles

Eukaryotic: four kingdoms: protists, fungi, plants, and animals

1. A biologist studying interactions between an animal species and its environment is studying biology at which level?

2. Which of the following is not considered an organism?

3. To which domain of life do humans belong?

4. DNA is found in the nucleus of

d. unicellular organisms only.

5. Which is a chemical product of photosynthesis that is used by consumers?

6. Which of the following processes provides the raw material for the other three to occur?

7. Some poisonous organisms are brightly colored, which warns others not to eat them. Which theme does this best represent?

c. the cellular basis of life

15. Describe the natural selection process.

19. Analyzing Diagrams Study the incomplete diagram below and answer the following questions.

a. Describe the purpose of a diagram such as this one.

b. Create a list of items that you would place in the blank section of this diagram. Include at least eight items on your list.

c. How would you label each section? Explain your answer.

20. Making Generalizations You have read that an ecosystem is a system, and a system is dependent on the interaction of its parts. What do you think might happen in an ecosystem if it lost all of its plant species?

21. Evaluating Models Describe how your home could be considered an ecosystem.

24. What's Wrong With These Statements?
Briefly explain why each statement is inaccurate or misleading.
a. Many organs working together make up a tissue.
b. Energy is recycled constantly in an ecosystem.
c. DNA is made of genes.

23. Evaluating the Impact of Research Discuss a few positive ways in which the study of biology has affected you.

22. Relating Cause and Effect In this chapter you read that DNA is responsible for the similarities between animal parents and their offspring. You also read that DNA is responsible for variations in organisms of the same population. Explain how both these statements can be true.

At every step of the biological hierarchy, structure and function are connected. For example, different cells have specific components that help them carry out their duties. Red blood cells, which carry oxygen, are formed differently than the white blood cells that fight infection. The relationship between structure and function is also apparent in entire organisms and the physiological systems that serve them. A cat’s long, sensitive whiskers gather information from its environment.

All organisms interact with their environment, which includes both organic and inorganic components. Material and energy flow back and forth. For instance, green plants use water, carbon dioxide and sunlight from their environment to produce their own energy through photosynthesis, but they release oxygen as a byproduct.

All Courses

Overview of ocean issues and organizations involved with marine activities, management, education, research, and business. Exploration of internships, research, and career opportunities. Preparation of resumes, proposals, and professional presentations. Not a BIOL major elective. (Cross-listed as IS 100)

BIOL 123 - Hawaiian Environment Science (3)

Characteristics of science and interaction with society illustrated by topics in geology, astronomy, oceanography, and biology of Hawaiian Islands. Not a BIOL major elective. DB

BIOL 171 - Introduction to Biology I (3)

Introductory biology for all life science majors. Cell structure and chemistry growth, reproduction, genetics, evolution, viruses, bacteria, and simple eukaryotes. Pre: CHEM (131, 151, 161, 171, or 181A) or concurrent, and BIOL 171L (or concurrent), or consent. DB

BIOL 171L - Introduction to Biology I Lab (1)

(1 3-hr Lab) Laboratory to accompany 171. Pre: CHEM (131, 151, 161, 171, or 181A) or concurrent, and BIOL 171 (or concurrent) or consent. DY

BIOL 172 - Introduction to Biology II (3)

Anatomy, physiology, and systematics of plants and animals behavior ecosystems, populations, and communities. Pre: CHEM (131, 151, 161, 171, or 181A) or concurrent, and BIOL 172L (or concurrent), or consent. DB

BIOL 172L - Introduction to Biology II Lab (1)

(1 3-hr Lab) Laboratory to accompany 172. Pre: CHEM (131, 151, 161, 171, or 181A) or concurrent, and BIOL 172 (or concurrent) or consent. DY

BIOL 220 - Biostatistics (3)

Introduction to statistical approaches in biology. Students will learn how to formulate hypotheses, test them quantitatively, and present results. Students will analyze biological datasets using the computer language . A-F only. Pre: 171, 172 or BOT 101 and BIOL/BOT 220L (or concurrent) and MATH 134 or MATH assessment exam (with score required for MATH 140). (Cross-listed as BOT 220)

BIOL 220L - Biostatistics Lab (1)

Laboratory to accompany BIOL 220. A-F only. Pre: 171 or 172 or BOT 101 and 220 (or concurrent) and MATH 134 or MATH assessment exam (with score for MATH 140). (Cross-listed as BOT 220L) .

BIOL 265 - Ecology and Evolutionary Biology (3)

Principles of ecology and evolution for life science majors stressing integrated approach and recent advance. A-F only. Pre: C (not C-) or better in 171/171L, 172, 172L (or concurrent), and 265L (or concurrent). DB

BIOL 265L - Ecology and Evolutionary Biology Lab (1)

(1 3-hr Lab) Laboratory to accompany 265. Pre: C (not C-) or better in 265 (or concurrent). DY

BIOL 275 - Cell and Molecular Biology (3)

Integrated cell and molecular biology for life science majors. Modern advances in recombinant DNA technology. A-F only. Pre: C (not C-) or better in 171/171L and CHEM 272. DB

BIOL 275L - Cell and Molecular Biology Lab (1)

(1 4-hr Lab) Laboratory for Cell and Molecular Biology. A-F only. Pre: C (not C-) or better in 275 (or concurrent) and CHEM 272. DY

BIOL 295 - Service Learning for Biology Majors (V)

Directed participation on tutorials and related activities in public schools and approved community and UH Mânoa organizations. A-F only. Repeatable one time. Pre: 265/265L, 275/275L, and consent.

BIOL 301 - Marine Ecology and Evolution (3)

Functional, ecological, and evolutionary problems faced by life in the sea. Draws from major marine habitats and associated communities, from the deep sea to the plankton. Impacts of overfishing, marine pollution, and land development on the ecology and evolution of marine organisms. Emphasis on developing problem solving and quantitative skills. A-F only. Pre: C (not C-) or better in 265/265L, 301L (or concurrent), and OCN 201 or consent. DB

BIOL 301L - Marine Ecology and Evolution Lab (2)

(1 3-hr Lab) Laboratory to accompany 301. A-F only. Pre: C (not C-) or better in 301 (or concurrent). DY

BIOL 304 - Biotechnology: Science and Ethical Issues (3)

Introduction to the concepts, goals, ethical issues and consequences of biotechnology using real-life case studies of GMOs, cloning, DNA fingerprinting, gene therapy and genetical engineering. Pre: 171 or consent. (Cross-listed as MBBE 304)

BIOL 305 - Ecology (3)

General survey of the principles of ecology. Focus on processes influencing the distribution and abundance of organisms, interactions among organisms, and interactions between organisms and the environment. A-F only. Pre: BIOL 171 BIOL 172 or BOT 201. (Cross-listed as BOT 305) DB

BIOL 306 - Ethology (3)

Introduction to animal and human ethology and sociobiology emphasis on social and interspecific behavior, its causes and adaptive significance. Lab optional. Pre: 171 and 171L and 172 and 172L or ANSC 201 or consent. DB

BIOL 306L - Ethology Laboratory (1)

(1 3-hr Lab) Application of methods in demonstrations, films, and projects. Pre: 306 (or concurrent). DY

BIOL 310 - Environmental Issues (3)

Global environmental problems in historical perspective physical, biological, sociocultural views. Pre: one of 101, 123, or GEOG 101 or consent. DB

BIOL 320 - The Atoll (3)

Atoll as ecosystem and as human environment. Formation, structure, distribution, biota. Pre: two semesters of introductory science or consent. DB

BIOL 325 - Vertebrate Zoology (3)

Introduction to the evolution and systematics of vertebrates, with emphasis on comparative morphology, physiology, and ecology. Pre: BIOL 265. Co-requisite: 325L. DB

BIOL 325L - Vertebrate Zoology Laboratory (2)

(2 3-hr Lab) Laboratory to accompany 325. Pre: BIOL 172 and BIOL 172L. Co-requisite: 325. DY

BIOL 331 - Marine Mammal Biology (3)

Overview of marine mammal science, significance and roles of marine mammals in their ecosystems, and marine conservation issues. Current research topics in marine mammal science will also be covered. Pre: C (not C-) or better in 171/171L, 172/172L, and 265, 265L or consent. DB

BIOL 331L - Marine Mammal Biology Lab (2)

Laboratory to accompany 331. Activities will include taxonomy, anatomy, morphology, necropsy, hematology, population estimating methods, tracking, field distribution surveys, stranding response, and energetics, and/or similar depending on field access and availability of specimens. A-F only. Pre: C (not C-) or better in 171/171L and 172/172L and 265/265L and 331 (or concurrent), or consent. DY

BIOL 340 - Genetics, Evolution and Society (3)

The role of genetics in evolution, medicine, behavior, plant and animal breeding and technology its impact on today’s society. Not a BIOL major elective. Pre: one semester of biological science at college level or consent. (Cross-listed as CMB 351) DB

BIOL 345 - Parasitology (2)

Animal parasites of man, and domestic and wild animals systematics, comparative morphology, life history, pathology, treatment, control. Pre: BIOL 275. DB

BIOL 345L - Parasitology Laboratory (2)

(2 3-hr Lab) Laboratory to accompany 345. Pre: 345 (or concurrent) and BIOL 275. DY

BIOL 350 - Sex Differences in the Life Cycle (3)

Human sex differences, their biological basis and significance genetic, hormonal, and behavioral determinants of sexual differentiation biology of gender, sexuality, parenting, menopause, and aging. Pre: one semester of biological science. (Cross-listed as WS 350) DB

BIOL 360 - Island Ecosystems (3)

Characteristics of island biota examples from Hawai'i and the Pacific. Impact of island and continental cultures policy and ecosystem endangerment contemporary legislation, policy, and management practices. Pre: one semester of biological science or consent. Not a BIOL major elective. DB

BIOL 363 - Biological Field Studies (V)

Biological survey, collection, and analysis techniques will be reviewed and applied through field studies. Students will be introduced to the uniqueness of the Hawaiian environment and its diversity of life. Emphasis on diversity, evolution and ecology. Repeatable up to six credits. A-F only. Pre: C (not C-) or better in 265/265L (or equivalent), or consent. DB

BIOL 375 - Genetics (3)

Genetic concepts at advanced undergraduate level genetic transmission, recombination, gene action, mutation, population and evolutionary genetics. A-F only. Pre: 275 or consent. DB

BIOL 375L - Genetics Laboratory (2)

(1 4-hr Lab) Experiments with a variety of organisms to illustrate principles discussed in BIOL 375. Pre: 275/275L, 375 (or concurrent) or consent. DY

BIOL 390 - Communicating in Biological Sciences (3)

Combined lecture/lab impart essential knowledge and skills in technical writing, poster design, and oral presentations for effective communication for life science majors. Research papers, lab reports, project proposals, conference presentations are covered. Life sciences majors only. Pre: C (not C-) or better in 171/171L, 172/172L, and ENG 100.

BIOL 395 - Internship in Biology Teaching (2)

Supervised laboratory internship in the preparation and demonstration of laboratory experiments in selected laboratory courses. Repeatable one time. Pre: consent.

BIOL 400 - Ocean Internships and Research (V)

Students carry out marine-related internships, practica, research projects or field experience on-or off-campus with faculty guidance. Repeatable one time. A-F only. Pre: minimum cum GPA of 2.5, junior or senior standing in any field of study and IS 100/BIOL 104 or consent, project proposal. (Cross-listed as IS 400)

BIOL 401 - Molecular Biotechnology (3)

General principles, applications, and recent advances of the rapidly growing science of biotechnology. Topics include impact of biotechnology on medicine, animal sciences, environment, agriculture, forensics, and economic and socio-ethical issues. Pre: C (not C-) or better in 275 or consent. (Cross-listed as MBBE 401) DB

BIOL 402 - Principles of Biochemistry (4)

Molecular basis of living processes in bacteria, plants, and animals emphasis on metabolism of carbohydrates, lipids, proteins, and nucleic acids. Pre: C (not C-) or better in 275/275L, and CHEM 273 or consent. (Cross-listed as MBBE 402) DB

BIOL 403 - Field Problems in Marine Biology (4)

Integrated program of intensive lectures, laboratory experiments, and field research that focus on the biological processes that shape the lives of marine organisms. A-F only. Limited space enrollment by consent GPA considered. Pre: C (not C-) or better in 301/301L and consent. DB

BIOL 404 - Advanced Topics in Marine Biology (3)

Current themes in marine biology and experience in scientific assessment. Repeatable two times. MBIO majors only. A-F only. Pre: C (not C-) or better in 301/301L or consent. DB

BIOL 406 - Biology of Marine Organisms (3)

Biology, physiology, and ecology of marine organisms and marine ecosystems, and the physical and chemical factors, which influence them. Cannot be used to satisfy BS-MB major requirements. Credit granted for only one of ZOOL 200, BIOL 301, or BIOL 406. Junior standing or consent. A-F only. Pre: 171 and 172.

BIOL 407 - Molecular Cell Biology I (3)

Relationship between structure and function at macromolecular level. Pre: C (not C-) or better in 275/275L and CHEM 273, or consent. DB

BIOL 408 - Molecular Cellular Biology II (3)

Cell structure and function. Structure, chemistry, and functions of organelles and macromolecules. Pre: C (not C-) or better in 407 or consent. (Cross-listed as MBBE 408 and MCB 408) DB

BIOL 408L - Advanced Molecular and Cellular Biology Laboratory (2)

(2 3-hr Lab) A laboratory to accompany 407 and 408. Pre: 407 (or concurrent) or 408 (or concurrent). (Cross-listed as MCB 408L) DY

BIOL 410 - Human Role in Environmental Change (3)

Human impacts through time on vegetation, animals, landforms, soils, climate, and atmosphere. Special reference to Asian/Pacific region. Implications of long-term environmental change for human habitability. Pre: with a minimum grade of B, one of 101, 123 or GEOG 101 and either 310 or GEOG 322 or consent. (Cross-listed as GEOG 410) DB

BIOL 411 - Corals and Coral Reefs (3)

The biogeography, evolution, ecology, and physiology of corals and coral reefs, and the application of this information to the management of coral reefs. Emphasis will be placed on processes such as dispersal, the evolution and operation of mutualisms, calcification, reproduction, and the maintenance of diversity. Pre: BIOL 265 (or concurrent) or BIOL 301 (or concurrent). (Spring only)

BIOL 425 - Wildlife and Plant Conservation (3)

Principles of conservation biology and wildlife management techniques, illustrated with animal, plant, and ecosystem examples. Examination of ethical, cultural, legal, political, and socio-economic issues impinging on conservation policy and practice. Group project and field trips. Pre: C (not C-) or better in 265/265L or consent. DB

BIOL 440 - Psychoactive Drug Plants (3)

Taxonomy, ecology, biochemistry, distribution, cultural history, and contemporary use of mind-altering drug plants examples from primitive, traditional, and modern societies. Pre: junior standing, one semester of biological science, and either ANTH 200 or GEOG 151 or consent. DB

BIOL 454 - Natural History of Hawaiian Islands (3)

(2 Lec, 1 1-hr Lab) Geography, geology, climatology, biotic environment of Pacific Basin and Hawaiian Islands endemism and evolution in terrestrial and marine biota. Pre: one semester of biological sciences at college level. (Cross-listed as BOT 450 and SUST 450) DB

BIOL 465 - Fish Diversity (3)

Survey of fish biodiversity focusing on major lineages, their phylogenetic relationships, and their geographic distribution in light of evolutionary history. Taught spring semester in alternate years. Junior standing or higher. Pre: BIOL 171 and BIOL 172. (Alt. years: spring) DB

BIOL 465L - Fish Diversity (1)

(2 2-hr Lab) Overview of the major orders and families of fishes of the world introduction to local Hawaiian fishes coverage of basic fish anatomy introduction to field and laboratory techniques in fish research. Junior standing or higher. Pre: 171, 172, and 465 (or concurrent). (Alt. years: spring)

BIOL 468 - The Rise of Fishes (3)

The origins and early evolution of fishes, with a focus on morphological innovations that have led to lineage divergence and adaptive radiation, and the nature of underlying processes associated with novel character trait evolution. A-F only. Pre: 265. (Alt. years: spring) DB

BIOL 470 - Evolutionary Biology (3)

Process of evolution: genetic basis, natural selection, population genetics, speciation, the fossil record. Pre: BIOL 171 and BIOL 172. Recommended: a BIOL or ZOOL course at 300 or 400 level. DB

BIOL 472 - The Biology of Cancer (3)

Integrative, in-depth focus on the genetics, cell biology, and molecular basis of cancer. Combination of classroom lectures and problem-based discussions in small groups. Addresses ethical implications of cancer research and treatment. A-F only. MCB or BIOL majors only. Senior standing or higher.

Prerequisite: 407 (or concurrent) and 408 (or concurrent) or consent. (Spring only) (Cross-listed as MCB 472).

BIOL 483 - Introduction to Bioinformatics Topics for Biologists (3)

Focuses on the use of computational tools and approaches to analyze the enormous amount of biological data (DNA, RNA, protein) available today. A-F only. Pre: 171 (or equivalent), or consent. (Once a year) (Cross-listed as MBBE 483)

BIOL 485 - Biology of the Invertebrates (3)

Body plans, development, cellular construction, physiological integration, natural history, and ecology of invertebrate animals. Emphasis on marine species, especially local ones. Pre: BIOL 172 and CHEM 161, or consent. Co-requisite: 485L. DB

BIOL 485L - Biology of the Invertebrates Laboratory (2)

(2 3-hr Lab) Pre: BIOL 172 and CHEM 161, or consent. Co-requisite: 485. DY

BIOL 490 - Mathematical Biology Seminar (1)

Reports on research in mathematical biology, reviews of literature, and research presentation. Required for Certificate in Mathematical Biology. Repeatable one time. Pre: junior standing or higher and consent. (Cross-listed as MATH 490)

BIOL 490 - Cancer Biology Section G (Developmental Biology) (V)

More details will be announced in the future.

BIOL 499 - Biological Problems (V)

Directed reading and research. For juniors and seniors majoring in life science 1-12 credits. Repeatable one time, up to 8 credits, up to 6 credits apply towards BA and BS BIOL major requirements. A-F only. Pre: 2.5 GPA minimum, written proposal and consent.

BIOL 501A - Biology Workshop for Science Teachers (V)

Principles taught in a conceptual and/or hands-on manner either in a laboratory setting or in the field. (B) biotechnology (C) ecology, evolution and conservation (D) marine biology (F) general biology. A-F only. Repeatable unlimited times. Pre: 171/171L, 172/172L, in-service teachers or consent.

BIOL 601 - Marine Biology-Environments and Organisms (4)

(3 hr Lec, 3 hr Lab) Introduction to the diversity of marine organisms and the many specialized coastal, reef, and oceanic habitats in which they live. Lab and field research exercises will complement lecture subjects. Graduate standing in Marine Biology graduate degree program only. A-F only. Pre: consent. (Fall only)

BIOL 602 - Marine Biology-Processes and Impacts (4)

(3 hr Lec, 3 hr Lab) Investigation of biological phenomena and processes related to productivity and food webs, community structure and ecology, adaptations, and physiology, and impacts of human activities and fisheries. Graduate standing in Marine Biology graduate degree program only. A-F only. Pre: 601. Minimum prerequisite grade of B. (Spring only)

BIOL 603 - Molecular Ecology (3)

Practical introduction to molecular methods used to address ecological and evolutionary questions. Advanced undergraduate/graduate level. Focus on methods and application to independent research project. A-F only. Pre: 265/265L (or equivalent) or 275/275L (or equivalent), and 375/375L, and consent. (Alt. years)

BIOL 650 - Population Genetics (3)

Mathematical, observational, experimental results on effects of mutation, selection, and systems of mating on distribution of genes. Analysis of non-experimental populations.

Prerequisite: Consent (Cross-listed as CMB 650)

ZOOL 101 - Principles of Zoology (3)

Structure, development, physiology, reproduction, evolution, behavior, and ecology of animals. DB

ZOOL 101L - Principles of Zoology Laboratory (1)

Laboratory to accompany 101. Pre: 101 (or concurrent). DY

ZOOL 200 - Marine Biology (2)

Biology and ecology of marine plants and animals coral reefs, the deep sea, rocky shores, marine mammals, fisheries, aquaculture, pollution, and conservation of marine resources. DB

ZOOL 200L - Marine Biology Laboratory (1)

(1 3-hr Lab) Laboratory, field trips to accompany 200. Pre: 200 (or concurrent). DY

ZOOL 399 - Directed Study (V)

ZOOL 416 - Histology (3)

Functional microanatomy of the animal body, emphasizing vertebrates. Oriented toward pre-professional students. Pre: BIOL 275. Recommended: BIOL 407. DB

ZOOL 416L - Histology Laboratory (2)

(2 2-hr Lab) Light microscopic study of animal tissues, especially vertebrates. Primarily for pre-professional students. Pre: BIOL 275. Recommended: BIOL 407. Co-requisite: 416. DY

ZOOL 417 - Microtechnique (3)

(2 Lec, 2 3-hr Lab) Preparation of animal tissues and organs for microscopic examination introduction to cytochemical and histochemical techniques. Pre: BIOL 275 or consent. DB

ZOOL 420 - Developmental Biology (3)

Fundamental principles, methods, concepts, and significance of developmental biology, emphasizing experimental methods. Pre: BIOL 275. Recommended: BIOL 407. DB

ZOOL 420L - Developmental Biology Laboratory (2)

(2 3-hr Labs) Analysis of animal development by experimental methods, using local organisms. Pre: 420 (or concurrent) and BIOL 275, or consent. Recommended: BIOL 407. DY

ZOOL 430 - Animal Physiology (3)

Introduction to function of organs, tissues, and cells, especially in vertebrates. Nerve and muscle physiology, endocrinology, circulation, respiration, excretion, and temperature regulation. A-F only. Pre: BIOL 275. Co-requisite: 430L. DB

ZOOL 430L - Animal Physiology Laboratory (2)

Laboratory investigation of function of organs, tissues, and cells, especially in vertebrates. Nerve and muscle physiology, circulation, membrane transport, respiration, excretion. Pre: BIOL 275. Co-requisite: 430. DY

ZOOL 432 - Comparative Physiology (3)

Physical-chemical cellular mechanisms underlying function of organ systems general principles inferable from study of adaption to diverse environments. Pre: BIOL 171 and 172, and MBBE 402 (or concurrent) or BIOC 441 (or concurrent) or consent. DB

ZOOL 439 - Animal Ecology (3)

Principles and theories examples from current experimental and analytical literature. For students in biological sciences. Pre: BIOL 265 and MATH 205 or MATH 215 or MATH 241 or consent. DB

ZOOL 439L - Animal Ecology Laboratory (2)

(1 4-hr Lab) Introduction to methodology, experience in characterizing populations and communities. Pre: BIOL 265. DY

ZOOL 442 - Introduction to Neuroscience (3)

Nerve cells, their signalling capabilities and the developmental organization of nervous systems, both invertebrate and vertebrate, for sensory reception, integration, behavioral command and learning insights from on-going research using molecular, genetic, biophysical, and imaging methods. Pre: BIOL 275 or consent. (Spring only)

ZOOL 460 - Avian Biology (3)

Broad coverage of the morphology, physiology, ecology, behavior, and evolution of birds, emphasizing the relation of birds to general theory in biology. Pre: BIOL 265. DB

ZOOL 466 - Fisheries Science (3)

General characteristics of fisheries harvesting methods principles and techniques to derive data and analyze fished populations. Field trips. Pre: one of the following: 410, 465, 470, 608, or 620 or consent. DB

ZOOL 467 - Ecology of Fishes (3)

Reproduction, early life history, age and growth, feeding, niche specificity, competitive interactions, communities, and evolutionary mechanisms. Pre: 465 or consent. DB

ZOOL 470 - Limnology (2)

Biology, physics, chemistry of lakes, streams, estuaries. Pre: BIOL 172 or consent. Co-requisite: 470L. DB

ZOOL 470L - Limnology Laboratory (1)

(1 3-hr Lab) Experimental and descriptive field projects on the biology, chemistry, hydrology, and physics of lakes, streams, and estuaries. Pre: BIOL 172 or consent. Co-requisite: 470. (Alt. years) DY

ZOOL 485 - Biogeography (3)

Distribution of plants and animals and processes that cause, maintain, and modify them. Approach is synthetic and dynamic. Pre: BIOL 172. DB

ZOOL 490A - Seminar in Zoology (1)

Reports on research, reviews of literature, or research experience. Required of students majoring in zoology or entomology. (B) general zoology (D) animal behavior (E) ecology (F) physiology (G) developmental biology (H) marine biology. Repeatable 2 times per alpha, credits earned for 3 credits only. Pre: 306 or equivalent or consent for (D).

ZOOL 492 - Teaching Internship (1)

Teaching internship in zoology. Required of ZOOL BS degree students. ZOOL BS majors only. CR/NC only. Pre: laboratory in an upper division ZOOL course.

ZOOL 499 - Directed Reading and Research (V)

Performance of a laboratory, field or library research project under the direction of a faculty advisor. Preparation of a proposal and written final report required. Limited to zoology majors.

ZOOL 500 - Masters Plan B/C Studies (1)

Enrollment for degree completion. Pre: master’s Plan B or C candidate and consent.

ZOOL 606 - Principles of Animal Behavior (2)

Critical review of theories of ethology, sociobiology social and interspecific behavior, communication, and evolutionary theory. Lab optional. Pre: graduate standing.

ZOOL 606L - Principles of Animal Behavior Laboratory (1)

(1 3-hr Lab) Group or individual research projects depending on interest of students. Pre: 606 (or concurrent).

ZOOL 607 - Genetics of Behavior and Evolution (1)

Introduces concepts and techniques in the genetics of behavior. Techniques inclued next gen sequencing, GWAS, and more. Student may use real data to analyze associations between genotype and phenotype.

ZOOL 608 - Fish Behavior and Sensory Biology (2)

Lectures, readings and presentations on sensory systems and behavior of fishes. A-F only. Pre: 306, 430, 465, 606 or consent. Co-requisite: 608L. (Alt. years)

ZOOL 608L - Fish Behavior and Sensory Biology Laboratory (1)

Laboratory study of fish sensory systems and behavior. A-F only. Pre: 306, 430, 465, 606 or consent. Co-requisite: 608. (Alt. years)

ZOOL 610 - Topics in Development and Reproductive Biology (V)

Discussion and survey of literature on specific topics some field and lab work may be required. Repeatable three times.

ZOOL 619 - Seminar on Science Teaching (2)

Effective teaching methods, organization of courses, lectures, laboratory exercises development and evaluation of examinations computers and audio-visual aids. Open to graduate students in various science disciplines. Repeatable one time. Cross-listed as NSCI619.

ZOOL 620 - Marine Ecology (3)

Principles of ecology of marine biota and environment. Pre: graduate standing in zoology, oceanography, or botany or consent.

ZOOL 623 - Quantitative Field Ecology (3)

(1 Lec, 1 2-hr Lab, 1 Discussion) Formal quantitative approach in identifying, designing, performing, analyzing, and interpreting ecological field problems. A-F only. Pre: 439, 439L, and 631 or consent. (Alt. years)

ZOOL 625 - Evolution in Marine Systems (3)

The course will focus on concepts of evolution applied to the unique natural history of marine species, such as sexual selection and the evolution of sperm-egg interactions in free-spawning taxa relationships among larval developmental mode, population genetic structure, geographic range, and rates of speciation and extinction in the fossil record the Cambrian Explosion marine biogeography, particularly the joint use of molecular phylogenetics and the fossil record to characterize spatial and temporal dynamics of species diversity in the coral triangle. (Crosslisted as MBIO 625)

Table of Contents

1 Evolution, the Themes of Biology, and Scientific Inquiry

Inquiring About Life

CONCEPT 1.1 The study of life reveals common themes 

CONCEPT 1.2 The Core Theme: Evolution accounts for the unity and diversity of life 

CONCEPT 1.3 In studying nature, scientists make observations and form and test hypotheses 

CONCEPT 1.4 Science benefits from a cooperative approach and diverse viewpoints 


2 The Chemical Context of Life

A Chemical Connection to Biology

CONCEPT 2.1 Matter consists of chemical elements in pure form and in combinations called compounds 

CONCEPT 2.2 An element&rsquos properties depend on the structure of its atoms 

CONCEPT 2.3 The formation and function of molecules depend on chemical bonding between atoms 

CONCEPT 2.4 Chemical reactions make and break chemical bonds 

3 Water and Life

The Molecule That Supports All of Life

CONCEPT 3.1 Polar covalent bonds in water molecules result in hydrogen bonding 

CONCEPT 3.2 Four emergent properties of water contribute to Earth&rsquos suitability for life 

CONCEPT 3.3 Acidic and basic conditions affect living organisms 

4 Carbon and the Molecular Diversity of Life 

Carbon: The Backbone of Life

CONCEPT 4.1 Organic chemistry is the study of carbon compounds 

CONCEPT 4.2 Carbon atoms can form diverse molecules by bonding to four other atoms 

CONCEPT 4.3 A few chemical groups are key to molecular function 

5 The Structure and Function of Large Biological Molecules

The Molecules of Life

CONCEPT 5.1 Macromolecules are polymers, built from monomers 

CONCEPT 5.2 Carbohydrates serve as fuel and building material 

CONCEPT 5.3 Lipids are a diverse group of hydrophobic molecules 

CONCEPT 5.4 Proteins include a diversity of structures, resulting in a wide range of functions 

CONCEPT 5.5 Nucleic acids store, transmit, and help express hereditary information 

CONCEPT 5.6 Genomics and proteomics have transformed biological inquiry and applications 


6 A Tour of the Cell

The Fundamental Units of Life

CONCEPT 6.1 Biologists use microscopes and biochemistry to study cells 

CONCEPT 6.2 Eukaryotic cells have internal membranes that compartmentalize their functions 

CONCEPT 6.3 The eukaryotic cell&rsquos genetic instructions are housed in the nucleus and carried out by the ribosomes 

CONCEPT 6.4 The endomembrane system regulates protein traffic and performs metabolic functions 

CONCEPT 6.5 Mitochondria and chloroplasts change energy from one form to another 

CONCEPT 6.6 The cytoskeleton is a network of fibers that organizes structures and activities in the cell 

CONCEPT 6.7 Extracellular components and connections between cells help coordinate cellular activities 

CONCEPT 6.8 A cell is greater than the sum of its parts

7 Membrane Structure and Function

Life at the Edge

CONCEPT 7.1 Cellular membranes are fluid mosaics of lipids and proteins 

CONCEPT 7.2 Membrane structure results in selective permeability 

CONCEPT 7.3 Passive transport is diffusion of a substance across a membrane with no energy investment 

CONCEPT 7.4 Active transport uses energy to move solutes against their gradients 

CONCEPT 7.5 Bulk transport across the plasma membrane occurs by exocytosis and endocytosis 

8 An Introduction to Metabolism

The Energy of Life

CONCEPT 8.1 An organism&rsquos metabolism transforms matter and energy, subject to the laws of thermodynamics 

CONCEPT 8.2 The free-energy change of a reaction tells us whether or not the reaction occurs spontaneously 

CONCEPT 8.3 ATP powers cellular work by coupling exergonic reactions to endergonic reactions 

CONCEPT 8.4 Enzymes speed up metabolic reactions by lowering energy barriers 

CONCEPT 8.5 Regulation of enzyme activity helps control metabolism 

9 Cellular Respiration and Fermentation

CONCEPT 9.1 Catabolic pathways yield energy by oxidizing organic fuels 

CONCEPT 9.2 Glycolysis harvests chemical energy by oxidizing glucose to pyruvate 

CONCEPT 9.3 After pyruvate is oxidized, the citric acid cycle completes the energy-yielding oxidation of organic molecules 

CONCEPT 9.4 During oxidative phosphorylation, chemiosmosis couples electron transport to ATP synthesis 

CONCEPT 9.5 Fermentation and anaerobic respiration enable cells to produce ATP without the use of oxygen 

CONCEPT 9.6 Glycolysis and the citric acid cycle connect to many other metabolic pathways 

10 Photosynthesis

The Process That Feeds the Biosphere

CONCEPT 10.1 Photosynthesis converts light energy to the chemical energy of food 

CONCEPT 10.2 The light reactions convert solar energy to the chemical energy of ATP and NADPH 

CONCEPT 10.3 The Calvin cycle uses the chemical energy of ATP and NADPH to reduce CO2 to sugar 

CONCEPT 10.4 Alternative mechanisms of carbon fixation have evolved in hot, arid climates

CONCEPT 10.5Life depends on photosynthesis  

11 Cell Communication

Cellular Messaging

CONCEPT 11.1 External signals are converted to responses within the cell 

CONCEPT 11.2 Reception: A signaling molecule binds to a receptor protein, causing it to change shape 

CONCEPT 11.3 Transduction: Cascades of molecular interactions relay signals from receptors to target molecules in the cell 

CONCEPT 11.4 Response: Cell signaling leads to regulation of transcription or cytoplasmic activities 

CONCEPT 11.5 Apoptosis integrates multiple cell-signaling pathways 

12 The Cell Cycle

The Key Roles of Cell Division

CONCEPT 12.1 Most cell division results in genetically identical daughter cells 

CONCEPT 12.2 The mitotic phase alternates with interphase in the cell cycle 

CONCEPT 12.3 The eukaryotic cell cycle is regulated by a molecular control system 


13 Meiosis and Sexual Life Cycles

Variations on a Theme

CONCEPT 13.1 Offspring acquire genes from parents by inheriting chromosomes 

CONCEPT 13.2 Fertilization and meiosis alternate in sexual life cycles 

CONCEPT 13.3 Meiosis reduces the number of chromosome sets from diploid to haploid 

CONCEPT 13.4 Genetic variation produced in sexual life cycles contributes to evolution 

14 Mendel and the Gene Idea

Drawing from the Deck of Genes

CONCEPT 14.1 Mendel used the scientific approach to identify two laws of inheritance 

CONCEPT 14.2 Probability laws govern Mendelian inheritance 

CONCEPT 14.3 Inheritance patterns are often more complex than predicted by simple Mendelian genetics 

CONCEPT 14.4 Many human traits follow Mendelian patterns of inheritance 

15 The Chromosomal Basis of Inheritance

Locating Genes Along Chromosomes

CONCEPT 15.1 Morgan showed that Mendelian inheritance has its physical basis in the behavior of chromosomes: scientific inquiry

CONCEPT 15.2 Sex-linked genes exhibit unique patterns of inheritance 

CONCEPT 15.3 Linked genes tend to be inherited together because they are located near each other on the same chromosome 

CONCEPT 15.4 Alterations of chromosome number or structure cause some genetic disorders 

CONCEPT 15.5 Some inheritance patterns are exceptions to standard Mendelian inheritance 

16 The Molecular Basis of Inheritance

Life&rsquos Operating Instructions

CONCEPT 16.1 DNA is the genetic material 

CONCEPT 16.2 Many proteins work together in DNA replication and repair 

CONCEPT 16.3 A chromosome consists of a DNA molecule packed together with proteins 

17 Gene Expression: From Gene to Protein

The Flow of Genetic Information

CONCEPT 17.1 Genes specify proteins via transcription and translation 

CONCEPT 17.2 Transcription is the DNA-directed synthesis of RNA: a closer look

CONCEPT 17.3 Eukaryotic cells modify RNA after transcription 

CONCEPT 17.4 Translation is the RNA-directed synthesis of a polypeptide: a closer look

CONCEPT 17.5 Mutations of one or a few nucleotides can affect protein structure and function 

18 Regulation of Gene Expression

Beauty in the Eye of the Beholder

CONCEPT 18.1 Bacteria often respond to environmental change by regulating transcription 

CONCEPT 18.2 Eukaryotic gene expression is regulated at many stages 

CONCEPT 18.3 Noncoding RNAs play multiple roles in controlling gene expression 

CONCEPT 18.4 A program of differential gene expression leads to the different cell types in a multicellular organism 

CONCEPT 18.5 Cancer results from genetic changes that affect cell cycle control 

A Borrowed Life

CONCEPT 19.1 A virus consists of a nucleic acid surrounded by a protein coat 

CONCEPT 19.2 Viruses replicate only in host cells 

CONCEPT 19.3 Viruses and prions are formidable pathogens in animals and plants 

20 DNA Tools and Biotechnology

The DNA Toolbox

CONCEPT 20.1 DNA sequencing and DNA cloning are valuable tools for genetic engineering and biological inquiry 

CONCEPT 20.2 Biologists use DNA technology to study gene expression and function 

CONCEPT 20.3 Cloned organisms and stem cells are useful for basic research and other applications 

CONCEPT 20.4 The practical applications of DNA-based biotechnology affect our lives in many ways 

21 Genomes and Their Evolution

Reading the Leaves from the Tree of Life

CONCEPT 21.1 The Human Genome Project fostered development of faster, less expensive sequencing techniques 

CONCEPT 21.2 Scientists use bioinformatics to analyze genomes and their functions 

CONCEPT 21.3 Genomes vary in size, number of genes, and gene density 

CONCEPT 21.4 Multicellular eukaryotes have a lot of noncoding DNA and many multigene families 

CONCEPT 21.5 Duplication, rearrangement, and mutation of DNA contribute to genome evolution 

CONCEPT 21.6 Comparing genome sequences provides clues to evolution and development 


22 Descent with Modification: A Darwinian View of Life

Endless Forms Most Beautiful

CONCEPT 22.1 The Darwinian revolution challenged traditional views of a young Earth inhabited by unchanging species

CONCEPT 22.2 Descent with modification by natural selection explains the adaptations of organisms and the unity and diversity of life 

CONCEPT 22.3 Evolution is supported by an overwhelming amount of scientific evidence 

23 The Evolution of Populations

The Smallest Unit of Evolution

CONCEPT 23.1 Genetic variation makes evolution possible

CONCEPT 23.2 The Hardy-Weinberg equation can be used to test whether a population is evolving 

CONCEPT 23.3 Natural selection, genetic drift, and gene flow can alter allele frequencies in a population 

CONCEPT 23.4 Natural selection is the only mechanism that consistently causes adaptive evolution 

24 The Origin of Species

That &ldquoMystery of Mysteries&rdquo

CONCEPT 24.1 The biological species concept emphasizes reproductive isolation 

CONCEPT 24.2 Speciation can take place with or without geographic separation 

CONCEPT 24.3 Hybrid zones reveal factors that cause reproductive isolation 

CONCEPT 24.4 Speciation can occur rapidly or slowly and can result from changes in few or many genes 

25 The History of Life on Earth

A Surprise in the Desert 

CONCEPT 25.1 Conditions on early Earth made the origin of life possible 

CONCEPT 25.2 The fossil record documents the history of life 

CONCEPT 25.3 Key events in life&rsquos history include the origins of unicellular and multicellular organisms and the colonization of land 

CONCEPT 25.4 The rise and fall of groups of organisms reflect differences in speciation and extinction rates 

CONCEPT 25.5 Major changes in body form can result from changes in the sequences and regulation of developmental genes 

CONCEPT 25.6 Evolution is not goal oriented 


26 Phylogeny and the Tree of Life

Investigating the Tree of Life

CONCEPT 26.1 Phylogenies show evolutionary relationships 

CONCEPT 26.2 Phylogenies are inferred from morphological and molecular data

CONCEPT 26.3 Shared characters are used to construct phylogenetic trees 

CONCEPT 26.4 An organism&rsquos evolutionary history is documented in its genome 

CONCEPT 26.5 Molecular clocks help track evolutionary time 

CONCEPT 26.6 Our understanding of the tree of life continues to change based on new data 

27 Bacteria and Archaea

Masters of Adaptation

CONCEPT 27.1 Structural and functional adaptations contribute to prokaryotic success 

CONCEPT 27.2 Rapid reproduction, mutation, and genetic recombination promote genetic diversity in prokaryotes 

CONCEPT 27.3 Diverse nutritional and metabolic adaptations have evolved in prokaryotes 

CONCEPT 27.4 Prokaryotes have radiated into a diverse set of lineages 

CONCEPT 27.5 Prokaryotes play crucial roles in the biosphere 

CONCEPT 27.6 Prokaryotes have both beneficial and harmful impacts on humans 

CONCEPT 28.1 Most eukaryotes are single-celled organisms 

CONCEPT 28.2 Excavates include protists with modified mitochondria and protists with unique flagella 

CONCEPT 28.3 SAR is a highly diverse group of protists defined by DNA similarities 

CONCEPT 28.4 Red algae and green algae are the closest relatives of land plants 

CONCEPT 28.5 Unikonts include protists that are closely related to fungi and animals 

CONCEPT 28.6 Protists play key roles in ecological communities 

29 Plant Diversity I: How Plants Colonized Land

The Greening of Earth

CONCEPT 29.1 Plants evolved from green algae 

CONCEPT 29.2 Mosses and other nonvascular plants have life cycles dominated by gametophytes 

CONCEPT 29.3 Ferns and other seedless vascular plants were the first plants to grow tall 

30 Plant Diversity II: The Evolution of Seed Plants

Transforming the World

CONCEPT 30.1 Seeds and pollen grains are key adaptations for life on land 

CONCEPT 30.2 Gymnosperms bear &ldquonaked&rdquo seeds, typically on cones 

CONCEPT 30.3 The reproductive adaptations of angiosperms include flowers and fruits 

CONCEPT 30.4 Human welfare depends on seed plants 

Mighty Mushrooms

CONCEPT 31.1 Fungi are heterotrophs that feed by absorption 

CONCEPT 31.2 Fungi produce spores through sexual or asexual life cycles 

CONCEPT 31.3 The ancestor of fungi was an aquatic, single-celled, flagellated protist 

CONCEPT 31.4 Fungi have radiated into a diverse set of lineages 

CONCEPT 31.5 Fungi play key roles in nutrient cycling, ecological interactions, and human welfare 

32 An Overview of Animal Diversity

A Kingdom of Consumers

CONCEPT 32.1 Animals are multicellular, heterotrophic eukaryotes with tissues that develop from embryonic layers 

CONCEPT 32.2 The history of animals spans more than half a billion years 

CONCEPT 32.3 Animals can be characterized by &ldquobody plans&rdquo 

CONCEPT 32.4 Views of animal phylogeny continue to be shaped by new molecular and morphological data

33 An Introduction to Invertebrates

A Dragon Without a Backbone

CONCEPT 33.1 Sponges are basal animals that lack tissues 

CONCEPT 33.2 Cnidarians are an ancient phylum of eumetazoans 

CONCEPT 33.3 Lophotrochozoans, a clade identified by molecular data, have the widest range of animal body forms 

CONCEPT 33.4 Ecdysozoans are the most species-rich animal group

CONCEPT 33.5 Echinoderms and chordates are deuterostomes 

34 The Origin and Evolution of Vertebrates

Half a Billion Years of Backbones

CONCEPT 34.1 Chordates have a notochord and a dorsal, hollow nerve cord 

CONCEPT 34.2 Vertebrates are chordates that have a backbone 

CONCEPT 34.3 Gnathostomes are vertebrates that have jaws 

CONCEPT 34.4 Tetrapods are gnathostomes that have limbs 

CONCEPT 34.5 Amniotes are tetrapods that have a terrestrially adapted egg 

CONCEPT 34.6 Mammals are amniotes that have hair and produce milk 

CONCEPT 34.7 Humans are mammals that have a large brain and bipedal locomotion 


35 Vascular Plant Structure, Growth, and Development

Are Plants Computers?

CONCEPT 35.1 Plants have a hierarchical organization consisting of organs, tissues, and cells 

CONCEPT 35.2 Different meristems generate new cells for primary and secondary growth 

CONCEPT 35.3 Primary growth lengthens roots and shoots 

CONCEPT 35.4 Secondary growth increases the diameter of stems and roots in woody plants 

CONCEPT 35.5 Growth, morphogenesis, and cell differentiation produce the plant body 

36 Resource Acquisition and Transport in Vascular Plants

A Whole Lot of Shaking Going On

CONCEPT 36.1 Adaptations for acquiring resources were key steps in the evolution of vascular plants 

CONCEPT 36.2 Different mechanisms transport substances over short or long distances 

CONCEPT 36.3 Transpiration drives the transport of water and minerals from roots to shoots via the xylem 

CONCEPT 36.4 The rate of transpiration is regulated by stomata 

CONCEPT 36.5 Sugars are transported from sources to sinks via the phloem 

CONCEPT 36.6 The symplast is highly dynamic 

37 Soil and Plant Nutrition

The Corkscrew Carnivore

CONCEPT 37.1 Soil contains a living, complex ecosystem

CONCEPT 37.2 Plant roots absorb essential elements from the soil

CONCEPT 37.3 Plant nutrition often involves relationships with other organisms 

38 Angiosperm Reproduction and Biotechnology

Flowers of Deceit

CONCEPT 38.1 Flowers, double fertilization, and fruits are key features of the angiosperm life cycle 

CONCEPT 38.2 Flowering plants reproduce sexually, asexually, or both 

CONCEPT 38.3 People modify crops by breeding and genetic engineering 

39 Plant Responses to Internal and External Signals

Stimuli and a Stationary Life

CONCEPT 39.1 Signal transduction pathways link signal reception to response 

CONCEPT 39.2 Plant hormones help coordinate growth, development, and responses to stimuli 

CONCEPT 39.3 Responses to light are critical for plant success 

CONCEPT 39.4 Plants respond to a wide variety of stimuli other than light

CONCEPT 39.5 Plants respond to attacks by pathogens and herbivores 


40 Basic Principles of Animal Form and Function

Diverse Forms, Common Challenges

CONCEPT 40.1 Animal form and function are correlated at all levels of organization 

CONCEPT 40.2 Feedback control maintains the internal environment in many animals 

CONCEPT 40.3 Homeostatic processes for thermoregulation involve form, function, and behavior 

CONCEPT 40.4 Energy requirements are related to animal size, activity, and environment 

41 Animal Nutrition

CONCEPT 41.1 An animal&rsquos diet must supply chemical energy, organic building blocks, and essential nutrients 

CONCEPT 41.2 Food processing involves ingestion, digestion, absorption, and elimination 

CONCEPT 41.3 Organs specialized for sequential stages of food processing form the mammalian digestive system 

CONCEPT 41.4 Evolutionary adaptations of vertebrate digestive systems correlate with diet 

CONCEPT 41.5 Feedback circuits regulate digestion, energy storage, and appetite 

42 Circulation and Gas Exchange

CONCEPT 42.1 Circulatory systems link exchange surfaces with cells throughout the body 

CONCEPT 42.2 Coordinated cycles of heart contraction drive double circulation in mammals 

CONCEPT 42.3 Patterns of blood pressure and flow reflect the structure and arrangement of blood vessels 

CONCEPT 42.4 Blood components function in exchange, transport, and defense 

CONCEPT 42.5 Gas exchange occurs across specialized respiratory surfaces 

CONCEPT 42.6 Breathing ventilates the lungs 

CONCEPT 42.7 Adaptations for gas exchange include pigments that bind and transport gases 

Recognition and Response

CONCEPT 43.1 In innate immunity, recognition and response rely on traits common to groups of pathogens 

CONCEPT 43.2 In adaptive immunity, receptors provide pathogen-specific recognition 

CONCEPT 43.3 Adaptive immunity defends against infection of body fluids and body cells 

CONCEPT 43.4 Disruptions in immune system function can elicit or exacerbate disease 

44 Osmoregulation and Excretion

A Balancing Act

CONCEPT 44.1 Osmoregulation balances the uptake and loss of water and solutes 

CONCEPT 44.2 An animal&rsquos nitrogenous wastes reflect its phylogeny and habitat 

CONCEPT 44.3 Diverse excretory systems are variations on a tubular theme 

CONCEPT 44.4 The nephron is organized for stepwise processing of blood filtrate 

CONCEPT 44.5 Hormonal circuits link kidney function, water balance, and blood pressure 

45 Hormones and the Endocrine System

The Body&rsquos Long-Distance Regulators 

CONCEPT 45.1 Hormones and other signaling molecules bind to target receptors, triggering specific response pathways 

CONCEPT 45.2 Feedback regulation and coordination with the nervous system are common in hormone pathways 

CONCEPT 45.3 Endocrine glands respond to diverse stimuli in regulating homeostasis, development, and behavior 

46 Animal Reproduction

Let Me Count the Ways

CONCEPT 46.1 Both asexual and sexual reproduction occur in the animal kingdom 

CONCEPT 46.2 Fertilization depends on mechanisms that bring together sperm and eggs of the same species 

CONCEPT 46.3 Reproductive organs produce and transport gametes 

CONCEPT 46.4 The interplay of tropic and sex hormones regulates mammalian reproduction 

CONCEPT 46.5 In placental mammals, an embryo develops fully within the mother&rsquos uterus 

47 Animal Development

A Body-Building Plan

CONCEPT 47.1 Fertilization and cleavage initiate embryonic development 

CONCEPT 47.2 Morphogenesis in animals involves specific changes in cell shape, position, and survival 

CONCEPT 47.3 Cytoplasmic determinants and inductive signals regulate cell fate

48 Neurons, Synapses, and Signaling

Lines of Communication

CONCEPT 48.1 Neuron structure and organization reflect function in information transfer 

CONCEPT 48.2 Ion pumps and ion channels establish the resting potential of a neuron 

CONCEPT 48.3 Action potentials are the signals conducted by axons 

CONCEPT 48.4 Neurons communicate with other cells at synapses 

49 Nervous Systems

Command and Control Center

CONCEPT 49.1 Nervous systems consist of circuits of neurons and supporting cells 

CONCEPT 49.2 The vertebrate brain is regionally specialized 

CONCEPT 49.3 The cerebral cortex controls voluntary movement and cognitive functions 

CONCEPT 49.4 Changes in synaptic connections underlie memory and learning 

CONCEPT 49.5 Many nervous system disorders can be explained in molecular terms 

50 Sensory and Motor Mechanisms

Sense and Sensibility

CONCEPT 50.1 Sensory receptors transduce stimulus energy and transmit signals to the central nervous system 

CONCEPT 50.2 In hearing and equilibrium, mechanoreceptors detect moving fluid or settling particles 

CONCEPT 50.3 The diverse visual receptors of animals depend on light-absorbing pigments

CONCEPT 50.4 The senses of taste and smell rely on similar sets of sensory receptors 

CONCEPT 50.5 The physical interaction of protein filaments is required for muscle function

CONCEPT 50.6 Skeletal systems transform muscle contraction into locomotion 

51 Animal Behavior

The How and Why of Animal Activity

CONCEPT 51.1 Discrete sensory inputs can stimulate both simple and complex behaviors 

CONCEPT 51.2 Learning establishes specific links between experience and behavior 

CONCEPT 51.3 Selection for individual survival and reproductive success can explain diverse behaviors 

CONCEPT 51.4 Genetic analyses and the concept of inclusive fitness provide a basis for studying the evolution of behavior 

52 An Introduction to Ecology and the Biosphere

Discovering Ecology

CONCEPT 52.1 Earth&rsquos climate varies by latitude and season and is changing rapidly 

CONCEPT 52.2 The distribution of terrestrial biomes is controlled by climate and disturbance 

CONCEPT 52.3 Aquatic biomes are diverse and dynamic systems that cover most of Earth

CONCEPT 52.4 Interactions between organisms and the environment limit the distribution of species 

CONCEPT 52.5Ecological change and evolution affect one another over long and short periods of time

53 Population Ecology

CONCEPT 53.1 Biotic and abiotic factors affectpopulation density, dispersion, and demographics 

CONCEPT 53.2 The exponential model describes population growth in an idealized, unlimited environment 

CONCEPT 53.3 The logistic model describes how a population grows more slowly as it nears its carrying capacity 

CONCEPT 53.4 Life history traits are products of natural selection 

CONCEPT 53.5 Density-dependent factors regulate population growth

CONCEPT 53.6 The human population is no longer growing exponentially but is still increasing rapidly 

54 Community Ecology

Communities in Motion

CONCEPT 54.1 Community interactions are classified by whether they help, harm, or have no effect on the species involved 

CONCEPT 54.2 Diversity and trophic structure characterize biological communities 

CONCEPT 54.3 Disturbance influences species diversity and composition 

CONCEPT 54.4 Biogeographic factors affect community diversity 

CONCEPT 54.5 Pathogens alter community structure locally and globally 

55 Ecosystems and Restoration Ecology

Transformed to Tundra

CONCEPT 55.1 Physical laws govern energy flow and chemical cycling in ecosystems 

CONCEPT 55.2 Energy and other limiting factors control primary production in ecosystems 

CONCEPT 55.3 Energy transfer between trophic levels is typically only 10% efficient 

CONCEPT 55.4 Biological and geochemical processes cycle nutrients and water in ecosystems 

CONCEPT 55.5 Restoration ecologists return degraded ecosystems to a more natural state 

56 Conservation Biology and Global Change

Psychedelic Treasure

CONCEPT 56.1 Human activities threaten Earth&rsquos biodiversity 

CONCEPT 56.2 Population conservation focuses on population size, genetic diversity, and critical habitat 

CONCEPT 56.3 Landscape and regional conservation help sustain biodiversity 

CONCEPT 56.4 Earth is changing rapidly as a result of human actions

CONCEPT 56.5 Sustainable development can improve human lives while conserving biodiversity