CAMPBELL

BIOLOGY Reece • Urry • Cain • Wasserman • Minorsky • Jackson

© 2014 Pearson Education, Inc.

TENTH EDITION

1 Evolution, the Themes of Biology, and Scientific Inquiry

Lecture Presentation by Nicole Tunbridge and Kathleen Fitzpatrick

Inquiring About Life

• An organism’s adaptations to its environment are the result of evolution – For example, the seeds of the dandelion are

moved by wind due to their parachute-like structures

• Evolution is the process of change that has transformed life on Earth

Figure 1.1

Biology is the scientific study of life. Biologists ask questions such as:

How a single cell develops into an organism? How the human mind works ? How living things interact in communities?

Life defies a simple, one-sentence definition Life is recognized by what living things do

The study of life reveals common themes

• Biology is a subject of enormous scope • There are five unifying themes

– Organization – Information – Energy and matter – Interactions – Evolution

Figure 1.2

Order

Energy processing

Growth and development

Regulation

Reproduction

Response to the environment

Evolutionary adaptation

Some properties of life

The themes of this book make connections across different areas of biology

• Biology consists of more than memorizing factual details

• Themes help to organize biological information • Theme: New Properties Emerge at Each Level in

the Biological Hierarchy • Life can be studied at different levels, from

molecules to the entire living planet • The study of life can be divided into different

levels of biological organization • Biological organization is based on a hierarchy of

structural levels, each building on the levels below.

Emergent Properties • Emergent properties result from the arrangement

and interaction of parts within a system • Each level of biological organization has

emergent properties. They are due to the arrangement and interactions of parts as complexity increases.

• Emergent properties characterize non biological entities as well

– For example, a functioning bicycle emerges only when all of the necessary parts connect in the correct way.

Figure 1.3

1 The Biosphere 7 Tissues

8 Cells

5 Organisms

10 Mole- cules

3 Communities

2 Ecosystems

6 Organs and Organ Systems

4 Populations

9 Organelles

Atoms and Molecules

• Atoms are simplest form organized into complex biological molecules.

• A molecule is a

chemical structure consisting of two or more atoms.

• Biological molecules are organized into structures called organelles, the components of cells.

1 µm

• Cells are the fundamental structure and functional unit of living organisms.

Cell

Individual living things are called Organisms

Some organisms consist of an unicellular others are multicellular in structure.

All organisms whether unicellular or multicellular must accomplish the same functions like uptake and processing of nutrients, excretion of wastes, response to environmental stimuli, and reproduction.

Tissues, Organs, and Organ Systems

• In multicellular organisms exhibit three structural levels above the cell:- similar cells are grouped into tissues, several tissues coordinate to form organs, and several organs form an organ system.

Organisms make up populations, localized groups of organisms belonging to the same species

Populations of several species in the same area combine to form a biological community.

Populations interact with

their physical environment to form an ecosystem.

The biosphere consists of

all the environments on Earth that are inhabited by life.

The Power and Limitations of Reductionism

• Reductionism is the reduction of complex systems to simpler components that are more manageable to study - For example, studying the molecular structure of

DNA helps us to understand the chemical basis of inheritance

• An understanding of biology balances reductionism with the study of emergent properties – For example, new understanding comes from

studying the interactions of DNA with other molecules

Prokaryotic and Eukaryotic Cells

Eukaryotic Cells Protista, fungi, plants and Animals Membrane enclosed organelles Nucleus present In general they are ten time larger

in size and more complex than prokaryotic cells.

Prokaryotic Cells Bacteria and Archaea microorganisms No membrane enclosed organelles-no nucleus. In general they are smaller in size (microscopic) and less complex than eukaryotic cells.

Nucleus

Membranes Cytoplasm

DNA

Membrane

Figure 1.4

The Cell is the lowest level of organization that can perform all activities required for life.

• Every cell is enclosed by a

membrane that regulates the passage of materials between the cell and its surroundings.

• Every cell uses DNA as its genetic information.

Cells are an organism’s basic units of structure and function.

Figure 1.5

Theme: Life’s Processes Involve the Expression and Transmission of Genetic Information

Chromosomes contain a cell’s genetic material in the form of DNA (deoxyribonucleic acid).

Each chromosome has one very long DNA molecule that contains hundreds or thousands of genes arranged along its length.

The DNA of chromosomes replicates as a cell prepares to divide. A Parental cell divides into two cellular offspring cells that inherit a complete set of genes.

DNA is the substance of Genes. Genes are the units of inheritance

that transmit information from parents to offspring.

Chromosomes Figure 1.5

Figure 1.6

Sperm cell

Egg cell

Fertilized egg with DNA from both parents Embryo’s cells

with copies of inherited DNA

Offspring with traits inherited from both parents

Nuclei containing DNA

Inherited DNA directs the development of an organism

Cell division transmits copies of genes to trillions of cells.

An organism’s Genome is its entire set of genetic instructions.

Figure 1.7

Nucleus DNA

(a) DNA double helix (b) Single strand of DNA

A

T

G

G

T

A

T

A

C

A

C

T

A

C

Nucleotide

Cell

Each DNA molecule is made up of two long chains arranged in a double helix Each link of a chain is one of four kinds of chemical building blocks called nucleotides and nicknamed A, G, C, and T

Nucleus → DNA → Double Helix Nulceotides

DNA Structure

DNA to Proteins The specific sequence of nucleotides along the DNA strand

is transcribed into RNA (ribonucleic acid) which is then translated into a specific protein-think of specific nucleotide arrangements of DNA as protein blueprints.

-Genes control protein production indirectly-with the help of RNA and other cellular machinery.

-During translation all organisms use the same genetic code- the blueprint (specific nucleotide sequence) means the same thing to all organisms.

Large macromolecules that build and maintain the cell and carryout the cell’s activities.

Gene expression is the process of converting information from gene to cellular product

The chromosomes of each human cell contain about 3 billion nucleotides, including genes coding for about 75,000 kinds of proteins, each with a specific function!

Figure 1.8

Lens cell

(a) Lens cells are tightly packed with transparent proteins called crystallin.

(b) How do lens cells make crystallin proteins? Crystallin gene

DNA

mRNA

Chain of amino acids

Protein

Crystallin protein

TRANSCRIPTION

TRANSLATION

A C C A A A C C G A G T

T G G T T T G G C T C A

U G G U U U G G C U C A

PROTEIN FOLDING

Systems Biology • A system is a combination of components that

function together • Systems biology constructs models for the

dynamic behavior of whole biological systems • The systems approach poses questions such as

– How does a drug for blood pressure affect other organs?

– How does increasing CO2 alter the biosphere?

Systems biology at the cellular and molecular level

The entire nucleotide sequence of the human genome is known now

BUT We do not yet know how the activities

of these proteins are coordinated in cells and whole organisms!

Genomics: Large-Scale Analysis of DNA Sequences

• An organism’s genome is its entire set of genetic instructions

• The human genome and those of many other organisms have been sequenced using DNA-sequencing machines

• Genomics is the study of sets of genes within and between species

• Proteomics is the study of whole sets of proteins encoded by the genome (known as proteomes)

Advances in systems biology at the cellular and molecular level

– “High-throughput” technology-which

yields enormous amounts of data. – Bioinformatics- the use of computational

tools to process a large volume of data. – Interdisciplinary research teams including

engineers, medical scientists, physicists, chemists, mathematicians, and computer scientists as well as biologists.

Theme: Life Requires the Transfer and Transformation of Energy and Matter

• Every organism interacts with its environment, including nonliving factors and other organisms

• Both organisms and their environments are affected by the interactions between them – For example, a tree takes up water and minerals from

the soil and carbon dioxide from the air; the tree releases oxygen to the air and roots help form soil

• The input of energy from the sun and the transformation of energy from one form to another make life possible

• When organisms use energy to perform work, some energy is lost to the surroundings as heat

• As a result, energy flows through an ecosystem, usually entering as light and exiting as heat

Figure 1.9

ENERGY FLOW

Light energy Heat Chemical

energy

Plants take up chemicals from the soil

and air.

Chemicals Decomposers return chemicals to the soil.

Chemicals pass to organisms that eat the plants.

• Humans have modified our environment – For example, half the human-generated CO2

stays in the atmosphere and contributes to global warming

• Global warming is a major aspect of global climate change

• It is important to understand the effects of global climate change on the Earth and its populations

Energy Conversion and Flow and in an Ecosystem

Sunlight (energy) enters ecosystem. Producers (plants, photosynthetic organisms)

use sunlight to make sugar (chemical energy).

Consumers (animals) feed on producers and

other animals. They convert the chemical energy to kinetic and

thermal energy. Heat (thermal energy) exits the

ecosystem. NOTE: Chemical nutrients are recycled

within the ecosystem, energy flows through the ecosystem.

Sunlight

Producers absorb light energy and transform it into chemical energy.

Chemical Energy

Chemical energy in food is transferred from plants to consumers.

Energy flow from sunlight to producers to consumers

Ecosystems: An Organism’s Interactions with Other Organisms and the Physical

Environment

• Interactions between the components of the system ensure smooth integration of all the parts

• This holds true equally well for components of an ecosystem and the molecules in a cell

• At the ecosystem level, each organism interacts continuously with other organisms

• These interactions may be beneficial or harmful to one or both of the organisms

• Organisms also interact continuously with the physical factors in their environment, and the environment is affected by the organisms living there

Figure 1.10

Sunlight

Leaves take in carbon dioxide from the air and release oxygen.

Animals eat leaves and fruit from the tree, returning nutrients and minerals to the soil in their waste products.

Water and minerals in the soil are taken up by the tree through its roots.

Leaves absorb light energy from the sun.

Leaves fall to the ground and are decomposed by organisms that return minerals to the soil.

CO2

O2

Molecules: Interactions Within Organisms

• Interactions between components—organs, tissues, cells, and molecules—that make up living organisms are crucial to their smooth operation

• Cells are able to coordinate various chemical pathways through a mechanism called feedback

• Biological Systems rely on “supply and demand” • Work- (movement, cell division) requires

energy. • Chemical reactions provide this energy.

During periods of rest, the excess energy must be converted (by different enzymes/chemical reactions) to molecules that can be stored for future energy use.

Specialized proteins called Enzymes catalyze (or accelerate) specific chemical reactions to decompose or to convert molecules for storage.

• In many cases, specific chemical reactions are linked together into chemical pathways, each step utilizing a specific enzyme. Feedback mechanisms allow biological processes to self-regulate.

• Negative feedback means that as more of a product accumulates, the process that creates it slows and less of the product is produced. The most common form of regulation in living organisms is negative feedback, in which the response reduces the initial stimulus.

• Positive feedback means that as more of a product accumulates, the process that creates it speeds up and more of the product is produced.

Feedback mechanisms regulate biological systems.

Figure 1.11

Insulin

Circulation throughout body via blood

Insulin-producing cell in pancreas

STIMULUS: High blood glucose level

Neg

ativ

e fe

edba

ck

Liver and muscle cells

RESPONSE: Glucose uptake by liver and muscle cells

Structure and Function Are Correlated at All Levels of Biological Organization

• Structure and function of living organisms are closely related

– For example, a leaf is thin and flat, maximizing the capture of light by chloroplasts

– For example, the structure of a bird’s wing is adapted to flight by honey comb hollow bone, flight muscles.

– Mitochondria made for ATP energy production

(a) Wings

(c) Neurons

(b) Bones Infoldings of membrane

Mitochondrion

(d) Mitochondria- Power house of cell to generate energy (ATP)

0.5 µm 100 µm

Structure and function of living organisms are closely related

Evolution, the Core Theme of Biology

• Evolution is the one idea that makes logical sense of everything we know about living organisms

• The scientific explanation for both the unity and diversity of organisms is the concept that living organisms are modified descendants of common ancestors

• Differences among organisms are explained by the accumulation of heritable changes

• Many kinds of evidence support the occurrence of evolution

• Evolutionary mechanisms account for the unity and diversity of all species on Earth

Evolution accounts for the unity and diversity of life

Evolution unifies biology at different scales of size throughout the history of life on Earth

1.8 million species identified to date, but it is estimated

that the total number may be around 100+ million! Taxonomy is the branch of biology that names and

classifies species into a hierarchical order. Domains are the broadest levels of classification- Domains

are subdivided into Kingdoms and further it into Phylum, Phylum into Class, Class into Order, Order into Family, Family into Genus and finally Genus into species.

Fig. 1-12 Species Genus Family Order Class Phylum Kingdom Domain

Ursus americanus (American black bear)

Ursus

Ursidae

Carnivora

Mammalia

Chordata

Animalia

Eukarya

Classifying life

The Three Domains of Life Domain Bacteria: Most diverse and widespread

prokaryotes.

Domain Archaea: Many of these prokaryotes live in extreme environments.

• Domain Eukarya: Includes all Eukaryotes, both single and multicellular (Protista, Plantae, Fungi, and Animalia) which are distinguished by their modes of nutrition. The domain Eukarya includes three multicellular kingdoms: – Plantae, which produce their own food by photosynthesis – Fungi, which absorb nutrients from dead organism – Animalia, which ingest their food

Fig. 1-13 (a) DOMAIN BACTERIA

(b) DOMAIN ARCHAEA

(c) DOMAIN EUKARYA

Kingdom Protists

Kingdom Fungi

Kingdom Plantae

Kingdom Animalia

Bacteria and Archaea: Prokaryotic Many are single cell organisms Microscopic Kingdom Monera Eukarya Single celled Protists Kingdoms-Fungi, Plantae, Animalia

Photosynthesis-Autotroph

Decomposers Ingest other Organisms- Heterotroph

Figure 1.14

Cilia of windpipe cells

Cross section of a cilium

Cilia of Paramecium

0.1 µm

15 µm

5 µm

Unity in the Diversity of Life A striking unity underlies the diversity of life; for example:

DNA is the universal genetic blueprint common to all organisms

Unity is evident in many features of cell structure

Charles Darwin and the Theory of Natural Selection

• Charles Darwin published On the Origin of Species by Means of Natural Selection in 1859

• Darwin made two main points: – Species showed evidence of “descent with modification” from

common ancestors – Natural selection (evolutionary adaptation) is the mechanism

behind “descent with modification” • Darwin’s theory explained the duality of unity and diversity Fossils and other evidence document the evolution of life on Earth

over billions of years( see Figure-1.15)

Fig. 1-16

Charles Darwin- Father of Evolution

Figure 1.17

European robin

Gentoo penguin American flamingo

• Darwin observed that: – Individuals in a population have traits that vary – Many of these traits are heritable (passed from

parents to offspring) – More offspring are produced than survive – Competition is inevitable – Species generally suit their environment

Charles Darwin Observed Nature

Darwin inferred that: Individuals that are best suited to their

environment are more likely to survive and reproduce (healthy, fertile offspring)

Over many generations, more individuals in a population will have the advantageous heritable traits that enhance survival and reproductive success.

In other words, The environment “selects” for beneficial traits by Natural selection, its cumulative effects over generations of time, can produce new species from ancestral species.

Darwin made inferences from these observations to arrive at his theory of evolution

Figure 1.18

Population with varied inherited traits

Elimination of individuals with certain traits

1 2 Reproduction of survivors

3 Increasing frequency of traits that enhance survival and reproductive succes

4

Natural Selection- in Beetle

Fig. 1-19

Natural selection is often evident in adaptations of organisms to their way of life and environment Bat wings are an example of adaptation

The Tree of Life • “Unity in diversity” arises from “descent with modification”

– For example, the forelimb of the bat, human, horse and the whale flipper all share a common skeletal architecture

• Fossils provide additional evidence of anatomical unity from descent with modification

• Darwin proposed that natural selection could cause an ancestral species to give rise to two or more descendent species – For example, the finch species of the Galápagos Islands

• Evolutionary relationships are often illustrated with tree-like diagrams that show ancestors and their descendents

Fig. 1-20

COMMON ANCESTOR

Warbler finches

Insect-eaters Seed-eater

Bud-eater

Insect-eaters

Tree finches

Green warbler finch Certhidea olivacea

Gray warbler finch Certhidea fusca

Sharp-beaked ground finch Geospiza difficilis Vegetarian finch Platyspiza crassirostris

Mangrove finch Cactospiza heliobates

Woodpecker finch Cactospiza pallida

Medium tree finch Camarhynchus pauper

Large tree finch Camarhynchus psittacula

Small tree finch Camarhynchus parvulus

Large cactus ground finch Geospiza conirostris Cactus ground finch Geospiza scandens

Small ground finch Geospiza fuliginosa

Medium ground finch Geospiza fortis

Large ground finch Geospiza magnirostris

Ground finches

Seed-eaters

Cactus-flow

er-eaters

Descent with modification: adaptive radiation of 14 species of Finch on the Galápagos Islands

In studying nature, scientists make observations and then form and test

hypotheses • The word Science is derived from Latin and

means “to know” • Inquiry is the search for information and

explanation • The scientific process includes making

observations, forming logical hypotheses, and testing them

• There are two main types of scientific inquiry: discovery science and hypothesis-based science

Scientists combine two main forms of inquiry in their study of nature

Discovery science Scientists describe nature. Discovery science can lead to important conclusions through inductive reasoning-generalizations based on a large number of specific observations. Much of our understanding of nature has arisen from discovery science. For example, “the sun always rises in the east” Hypothesis-Based science Scientists explain nature. The observations and inductions obtained through discovery science stimulate scientists to identify the causes and explanations for the observations.

Making Observations & Analysis of Data

Biologists describe natural structures and processes. This approach is based on observation and the analysis

of data Data are recorded observations or items of information Data fall into two categories

– Qualitative-descriptions rather than measurements

For example, Jane Goodall’s observations of chimpanzee behavior.

– Quantitative-recorded measurements, which are sometimes organized into tables and graphs.

Figure 1.20

Jane Goodall collecting qualitative data on chimpanzee behavior

Hypothesis-Based Scientific Inquiry

Hypothesis-a tentative answer to a well-framed question.

Hypothesis-based science utilizes deductive reasoning- logic based on observations obtained through discovery science that allow scientists to make specific predictions if a particular hypothesis is correct.

For example, if organisms are made of cells (premise 1), and humans are organisms (premise 2), then humans are composed of cells (deductive prediction).

Hypotheses in Scientific Inquiry

A hypothesis must be testable and falsifiable. Hypothesis-based science often makes use of

two or more alternative hypotheses Failure to falsify a hypothesis does not prove

that hypothesis – For example, you replace your flashlight bulb,

and it now works; this supports the hypothesis that your bulb was burnt out, but does not prove it (perhaps the first bulb was inserted incorrectly)

Fig. 1-21

Observations

Question

Hypothesis #1: Dead batteries

Hypothesis #2: Burnt-out bulb

Prediction: Replacing batteries will fix problem

Prediction: Replacing bulb will fix problem

Test prediction Test prediction

Test falsifies hypothesis Test does not falsify hypothesis

Inductive reasoning- I’ve ob-served this before….. Deductive Reasoning #1-if the batteries are dead, then replacing them will fix the problem. Deductive Reasoning #2-if The bulb is burned out, then replacing it will fix the problem. The hypotheses are tested. No amount of experimental testing can prove a hypothesis beyond a shadow of doubt.

For example, Observation: Your flashlight doesn’t work Question: Why doesn’t your flashlight work? Hypothesis 1: The batteries are dead Hypothesis 2: The bulb is burnt out

Both these hypotheses are testable

The Scientific Method

An idealized “textbook” process of inquiry Very few scientific inquiries adhere rigidly to the sequential steps

outlined by the scientific method….why? Puzzling, or complex questions do not always prompt well-defined

questions. Sometimes scientists must wait for improved technologies/or

ideas to be developed to address key-questions. Sometimes scientists must re-direct their research when they

realize they have been asking the wrong questions.

X

The Flexibility of the Scientific Process

• The scientific method is an idealized process of inquiry

• Hypothesis-based science is based on the “textbook” scientific method but rarely follows all the ordered steps

• Backtracking and “rethinking” may be necessary part way through the process

Figure 1.23

EXPLORATION AND

DISCOVERY

FORMING AND

TESTING HYPOTHESES

SOCIETAL BENEFITS

AND OUTCOMES

COMMUNITY ANALYSIS

AND FEEDBACK

Theories in Science • In the context of science, a theory is:

– Broader in scope than a hypothesis – General, and can lead to new testable hypotheses – Supported by a large body of evidence in comparison to a

hypothesis

Model Building in Science Models are representations of natural phenomena and can take

the form of: Diagrams Three-dimensional objects Computer programs Mathematical equations

The test of a model’s success is how well it fits the available data, how comfortably it accommodates new observations, how accurately it predicts the outcomes of new experiments or observations, and how effectively it communicates.

Science benefits from a cooperative approach and diverse viewpoints

• Most scientists work in teams, which often include graduate and undergraduate students

• Good communication is important in order to share results through seminars, publications, and websites.

• Building on the Work of Others. -Scientists check each others’ claims by performing similar

experiments -It is not unusual for different scientists to work on the

same research question -Scientists cooperate by sharing data about model

organisms (e.g., the fruit fly Drosophila melanogaster)

Figure 1.23g

Team work of Scientist –discussing data during presentation of results

A Case Study in Scientific Inquiry: Investigating Coat Coloration in Mouse

Populations • Color patterns of animals vary widely in nature, sometimes even

between members of the same species • Two populations of mice belonging to the same species

(Peromyscus polionotus) but with different color patterns are found in different environments

• The beach mouse lives on white sand dunes with sparse vegetation; the inland mouse lives on darker soil

• The two types of mice match the coloration of their habitats • Natural predators of these mice are all visual hunters • Francis Bertody Sumner hypothesized that the color patterns

had evolved as adaptations to protect the mice from predators • Hopi Hoekstra and a group of students tested this hypothesis

Figure 1.24

Florida

Inland population

Beach population

Beach population

GULF OF MEXICO

Inland population

Figure 1.25

Light models Dark models Light models Dark models

Camouflaged Non-camouflaged Non-camouflaged Camouflaged (control) (experimental) (experimental) (control)

Beach habitat Inland habitat

Perc

enta

ge o

f at

tack

ed m

odel

s 100

50

0

Results

The researchers predicted that mice that did not match their habitat would be preyed on more heavily than mice that did match the surroundings They built models of mice, painted them to match one of the surroundings, and placed equal numbers of each type of model in each habitat They then recorded signs of predation

The importance of controlled experiments

Controlled experiments-are designed to compare an experimental group with a control group.

Ideally experimental and control groups differ in only the

one factor under investigation Without controls the researchers would not be able to rule

out other factors besides model color that might have affected the results

Science and Technology are functions of Society

• The goal of science is to understand natural phenomena

• The goal of technology is to apply scientific knowledge for some specific purpose

• Science and technology are interdependent • Biology is marked by “discoveries,” while

technology is marked by “inventions” • With advances in technology come difficult

choices, can we do it? should we do it?

• The combination of science and technology has dramatic effects on society

– For example, the discovery of DNA by James Watson and Francis Crick allowed for advances in DNA technology such as testing for hereditary diseases

• Ethical issues can arise from new technology, but have as much to do with politics, economics, and cultural values as with science and technology

Figure 1.26 DNA technology and crime scene investigation

The Value of Diverse Viewpoints in Science

• Many important inventions have occurred where different cultures and ideas mix

– For example, the printing press relied on innovations from China (paper and ink) and Europe (mass production in mills)

• Science benefits from diverse views from different racial and ethnic groups, and from both women and men