themes in the study of biology © 2012 pearson education, inc. chapter 1 biology: exploring life

THEMES IN THE STUDY OF BIOLOGY

© 2012 Pearson Education, Inc.

Chapter 1 Biology: Exploring Life

1.1 All forms of life share common properties

Biology is the scientific study of life.

Properties of life include

1. Order—the highly ordered structure that typifies life,

2. Reproduction—the ability of organisms to reproduce their own kind,

3. Growth and development—consistent growth and development controlled by inherited DNA,

4. Energy processing—the use of chemical energy to power an organism’s activities and chemical reactions,


1.1 All forms of life share common properties

5. Response to the environment—an ability to respond to environmental stimuli,

6. Regulation—an ability to control an organism’s internal environment within limits that sustain life, and

7. Evolutionary adaptation—adaptations evolve over many generations as individuals with traits best suited to their environments have greater reproductive success and pass their traits to offspring.


Figure 1.1

(1) Order

(2) Reproduction

(3) Growth and development

(4) Energy processing

(7) Evolutionary adaptation

(6) Regulation

(5) Response to the environment

Figure 1.2Biosphere

Florida

EcosystemFlorida

Everglades

CommunityAll organisms in thiswetland ecosystem

PopulationAll alligators living

in the wetlands

Organisman American alligator

Organ systemNervous systemNerve

Spinalcord

Brain OrganBrain

TissueNervous tissue

CellNerve cell

Nucleus

OrganelleNucleus

MoleculeDNA

Atom

1.2 In life’s hierarchy of organization, new properties emerge at each level

Biological organization unfolds as follows:

– Biosphere—all of the environments on Earth that support life,

– Ecosystem—all the organisms living in a particular area and the physical components with which the organisms interact,

– Community—the entire array of organisms living in a particular ecosystem,

– Population—all the individuals of a species living in a specific area,



– Organism—an individual living thing,

– Organ system—several organs that cooperate in a specific function,

– Organ—a structure that is composed of tissues and that provides a specific function for the organism,

– Tissues—a group of similar cells that perform a specific function,

– Cells—the fundamental unit of life,



– Organelle—a membrane-bound structure that performs a specific function in a cell, and

– Molecule—a cluster of small chemical units called atoms held together by chemical bonds. Molecules that make up organelles in cells include large macromolecules like protein (made from 20 different amino acids), lipids (made from 30 fatty acids), disaccharides and polysaccharides (made from two to many monosaccharides), and nucleic acids (made from five nucleotides). Each of these are made of smaller molecules that are the building blocks of the macromolecules. DNA and RNA contain the blueprint for assembling small molecules into macromolecules.


1.3 Cells are the structural and functional units of life

Cells are the level at which the properties of life emerge.

A cell can

– regulate its internal environment,

– take in and use energy,

– respond to its environment,

– develop and maintain its complex organization, and

– give rise to new cells.



All cells

– are enclosed by a membrane that regulates the passage of materials between the cell and its surroundings and

– use DNA as their genetic information, which serves as a blueprint for making macromolecules.



There are two basic types of cells.

1. Prokaryotic cells

– were the first to evolve,

– are simpler, and

– are usually smaller than eukaryotic cells.

2. Eukaryotic cells

– contain membrane-enclosed organelles, including a nucleus containing DNA, and

– are found in plants, animals, and fungi.


Figure 1.3

Eukaryotic cell

Membrane

Prokaryoticcell

DNA(no nucleus)

Organelles

Nucleus(membrane-enclosed)

DNA (throughoutnucleus)

1.4 Living organisms interact with their environment, exchanging matter and energy

Living organisms interact with their environments, which include

– other organisms and

– physical factors.

In most ecosystems

– plants are the producers that provide the food,

– consumers eat plants and other animals, and

– decomposers act as recyclers, changing complex matter into simpler mineral nutrients.


Figure 1.4

ENERGY FLOW

Sun

Inflow oflight energy

Producers(plants)

Chemical energyin food

Consumers(animals)

Outflow ofheat

Leaves take upCO2 from air; rootsabsorb H2O andminerals from soil

Decomposers suchas worms, fungi,

and bacteria returnchemicals to soil

EVOLUTION, THE CORE THEME OF BIOLOGY


1.5 The unity of life is based on DNA and a common genetic code

All cells have DNA, the chemical substance of genes and the blueprint for making macromolecules.

Genes

– are the unit of inheritance that transmits information from parents to offspring,

– are grouped into very long DNA molecules called chromosomes, and

– control the activities of a cell.


1.5 The unity of life is based on DNA and a common genetic code

A species’ genes are the sequences of the four building blocks making up DNA’s double helix.

– All forms of life use essentially the same code to transcribe the information stored in DNA into RNA that is translated into proteins. Organelles are either made of proteins or the proteins form enzymes that make the three other macromolecules

– The diversity of life arises from differences in DNA sequences.

– Evolution is the changes in DNA over time in a species that can lead to adaptations in the species


Figure 1.5

A

T

T

C

C

G G C

TA

A T

GC

A

GC

GC

A T

1.6 The diversity of life can be arranged into three domains

Diversity is the hallmark of life.

– Biologists have identified about 1.8 million species.

– Estimates of the actual number of species ranges from 10 to 100 million.

Taxonomy names species and classifies them into a system of broader groups.


1.6 The diversity of life can be arranged into three domains

The diversity of life can be arranged into three domains.

1. Bacteria are the most diverse and widespread prokaryotes.

2. Archaea are prokaryotes that often live in Earth’s extreme environments.

3. Eukarya have eukaryotic cells and include

– single-celled members of the protist and fungal kingdoms and

– multicellular members of kingdoms including protists, fungi, animals, and plants.


Figure 1.6

Domain Bacteria

Domain Archaea

Domain Eukarya

Bacteria

Archaea

Protists(multiple kingdoms)

Kingdom Fungi Kingdom Animalia

Kingdom Plantae

1.7 Evolution explains the unity and diversity of life

The history of life, as documented by fossil species, is a saga of a changing Earth

– billions of years old and

– inhabited by an evolving cast of life forms.

Evolution accounts for life’s dual nature of

– kinship and

– diversity.



Natural selection was inferred by connecting two observations.

1. Individuals in a population vary in their traits due to differences in DNA, many of which are passed on from parents to offspring.

2. A population can produce far more offspring than the environment can support.


Figure 1.7C

Elimination of individuals with certain traits

Reproduction of survivors

Population with varied inherited traits1

3

2


From these observations, Charles Darwin first inferred that

– those individuals with heritable traits best suited to the environment are more likely to survive and reproduce than less well-suited individuals,

– as a result of this unequal reproductive success over many generations, an increasing proportion of individuals will have the advantageous traits, and

– the result will be evolutionary adaptation, the accumulation of favorable traits in a population over time.


Figure 1.7C List some adaptations for the snowy owl, flamingo, and penguin

THE PROCESS OF SCIENCE


1.8 Scientific inquiry is used to ask and answer questions about nature

The word science is derived from a Latin verb meaning “to know.” Science is a way of knowing.

Scientists

– draw general conclusions from many observations and

– come up with ways to test a hypothesis, a proposed explanation for a set of


1.8 Scientific inquiry is used to ask and answer questions about nature

How is a theory different from a hypothesis? A scientific theory is

– much broader in scope than a hypothesis,

– usually general enough to generate many new, specific hypotheses, which can then be tested, and

– supported by a large and usually growing body of evidence.


1.9 Scientists form and test hypotheses and share their results

We solve everyday problems by using hypotheses.

– A common example would be the reasoning we use to answer the question, “Why doesn’t a flashlight work?”

– Using reasoning we realize that the problem is either (1) the bulb or (2) the batteries.

– Further, a hypothesis must be

– testable and

– falsifiable.

– In this example, two hypotheses are tested.


Figure 1.9A_s1

Observation

Question

Hypothesis 1:Dead batteries

Hypothesis 2:Burned-out bulb

Figure 1.9A_s2

Observation

Question



Prediction: Prediction:

Replacing batterieswill fix problem.

Replacing bulbwill fix problem.

Experiment: Experiment:

Test prediction byreplacing batteries.

Test prediction byreplacing bulb.

Figure 1.9A_s3

Test falsifieshypothesis. Revisehypothesis orpose new one.

Observation

Question



Prediction: Prediction:

Replacing batterieswill fix problem.

Replacing bulbwill fix problem.

Experiment: Experiment:

Test prediction byreplacing batteries.

Test prediction byreplacing bulb.

Test does notfalsify hypothesis.Make additionalpredictions andtest them.


An actual research project demonstrates the process of science.

Scientists began with a set of observations and generalizations that

Camouflaged animals are protected from predation

They then tested the hypothesis that Peromyscus polionotus populations on the beach and inland that had coat patterns that did not match the environment would be more heavily predated



The scientists conducted a controlled experiment, comparing

– an experimental group consisting of plastic models that were not camouflaged like the environment

– control group consisting of models with coloration like the environment

– The groups differed only by one factor, the coloration of the mice models

– The data fit the key prediction of the camouflage hypothesis.


Beach mouse Inland mouse

-the noncamouflaged models had a higher percentage of attacks in the beach and inland habitats and these data fit the key prediction of the camouflage hypothesis

themes in the study of biology © 2012 pearson education, inc. chapter 1 biology: exploring life

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