1. Introduction: Themes in the Study of Life
Chapter 1
Introduction: Themes in the Study of Life
Copyright © 2011 Pearson Education, Inc.

2. KEY CONCEPTS Connections Across Different Areas of Biology
CORE THEME – Evolution important for unity and diversity of life
Studying Nature by Observations – Scientists’ Life
Co-operative Approach and Diverse Viewpoints Important for Sciences

3. Overview: Inquiring About Life
An organism’s adaptations to its environment are the result of evolution
For example, the ghost plant is adapted to conserving water; this helps it to survive in the crevices of rock walls
Evolution is the process of change that has transformed life on Earth

4. Biology is the scientific study of life
Biologists ask questions such as
How does a single cell develop into an organism?
How does the human mind work?
How do living things interact in communities?
Life defies a simple, one-sentence definition
Life is recognized by what living things do
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5. Which of the following properties or processes do we associate with living things?
a) evolutionary adaptations b) energy processing c) responding to the environment d) growth and reproduction e) all of the above
Answer: e

6. Properties of Life Figure 1.3 Some properties of life. Order
Response to
the environment
Evolutionary adaptation
Reproduction
Figure 1.3 Some properties of life.
Regulation
Energy processing
Growth and
development

7. What is the lowest level of biological organization that can perform all the activities required for life?
a) organelle—for example, a chloroplast b) cell—for example, a skin cell c) tissue—for example, nervous tissue d) organ system—for example, the reproductive system e) organism—for example, an amoeba, dog, human, or maple tree
Answer: b

8. New Properties in Biological Hierarchy
The biosphere
Tissues
Ecosystems
Organs and
organ systems
Communities
Cells
Organelles
Organisms
Atoms
Molecules
Populations
New Properties in Biological Hierarchy

9. Emergent Properties
Emergent properties result from the arrangement and interaction of parts within a system
Emergent properties characterize nonbiological entities as well
For example, a functioning bicycle emerges only when all of the necessary parts connect in the correct way

10. Which of the following scientific studies would represent an example of a “systems biology” approach?
measuring the effect of an invading insect that eats oak leaves on the numbers of oak trees and on any subsequent changes in the number and types of decomposer fungi in the soil
discovering the structure of an enzyme that is important in digestion of protein
comparing the microscopic structure of leaves of two different species of magnolias
measuring the reproductive rate of emperor penguins during exceptionally warm and exceptionally cold years
comparing the DNA sequence of two closely related plants and inferring their evolutionary histories
Answer: a In the past, most research has been conducted on one or two levels of complexity (e.g., cells or population levels). Recently, however, scientists or teams of scientists have been studying how processes at one level affect processes at other scales. This question is designed to help students see connections among levels. Answers c-e address scientific questions at only one level: c is a study at the tissue level, d is a study at the population level, and e is a study at the molecular level). Answer b is likely a study simply at the molecular level, but a student might argue that it addresses two levels—molecular and cellular. It could certainly be expanded to a systems study if the scientists also studied molecular forces and folding of the protein chain. Answer a is likely the best answer because the two-species interaction between the invading insect and the oak (community level) affects the abundance of oak trees (population level) and the process of decomposition (ecosystem level). A possible extension of this question would be to ask students to broaden all the answers into systems biology studies.

11. 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?

12. Energy Transfer
Like jackrabbits, elephants have many blood vessels in their ears that help them cool their bodies by radiating heat. Which of the following statements about this radiated energy would be accurate?
The original source of the energy was the sun.
The energy will be recycled through the ecosystem.
The radiated energy will be trapped by predators of the elephants.
More energy is radiated in cold conditions than in hot conditions.
More energy is radiated at night than during the day.
Answer: a
Energy is a concept that is essential for all students to understand. This question will help students understand a number of ideas about energy. Answer a is the correct answer and students should understand that the energy from the sun powers all living systems (except deep ocean vent communities). Energy is lost to the system as heat, whereas atoms can be used over and over again; thus, answer b is incorrect. Answer c is related to answer b and is incorrect because the heat that is radiated from the ears is not available to other organisms—only the energy stored in the tissues of the jackrabbit is available to the predator. Answers d and e are incorrect for similar reasons—that more heat is radiated when the jackrabbit is warmer (either in hot conditions or during the day).

13. Cycling of chemical nutrients
Sunlight
Leaves absorb light energy from the sun.
Leaves take in carbon dioxide from the air and release oxygen.
CO2 O2
Cycling of chemical nutrients
Animals eat
leaves and fruit
from the tree.
Leaves fall to the ground and are decomposed by organisms that return minerals to the soil.
Figure 1.5 Interactions of an African acacia tree with other organisms and the physical environment.
Water and minerals in the soil are taken up by the tree through its roots.

14. Theme: Life Requires Energy Transfer and Transformation
A fundamental characteristic of living organisms is their use of energy to carry out life’s activities
Work, including moving, growing, and reproducing, requires a source of energy
Living organisms transform energy from one form to another
For example, light energy is converted to chemical energy, then kinetic energy
Energy flows through an ecosystem, usually entering as light and exiting as heat

15. (a) Energy flow from sunlight to producers to consumers
Heat
When energy is used to do work, some energy is converted to thermal energy, which is lost as heat.
Producers absorb light energy and transform it into chemical energy.
An animal’s muscle cells convert chemical energy from food to kinetic energy, the energy of motion.
Chemical
energy
A plant’s cells use chemical energy to do work such as growing new leaves.
Chemical energy in food is transferred from plants to consumers.
(a) Energy flow from sunlight to producers to consumers
Figure 1.6 Energy flow in an ecosystem.
(b) Using energy to do work

16. Theme: 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

17. Theme: The Cell Is an Organism’s Basic Unit of Structure and Function
The cell is the lowest level of organization that can perform all activities required for life
All cells
Are enclosed by a membrane
Use DNA as their genetic information

18. The idea that form and function are related would not be exemplified by which of the following examples?
Cells in the intestinal lining of vertebrates have many small projections that increase the surface area for absorption of nutrients.
Plants that live in dry areas have large roots for absorbing water.
Seeds that are dispersed by wind are very light.
Fish that swim rapidly have bodies that are streamlined.
None of the above.
Answer: e
The relationship between form and function is very important and results from the action of natural selection. In this question, all answers show a relationship between form and function and therefore none of them connect correctly to the stem.

19. A eukaryotic cell has membrane-enclosed organelles, the largest of which is usually the nucleus
By comparison, a prokaryotic cell is simpler and usually smaller, and does not contain a nucleus or other membrane-enclosed organelles
Prokaryotic cell
DNA
(no nucleus)
Membrane
1 m

20. Nucleus (membrane- enclosed)
Figure 1.8
Prokaryotic cell
Eukaryotic cell
DNA
(no nucleus)
Membrane
Membrane
Cytoplasm
Figure 1.8 Contrasting eukaryotic and prokaryotic cells in size and complexity.
Nucleus (membrane- enclosed)
Membrane- enclosed organelles
DNA (throughout nucleus)
1 m

21. Theme: The Continuity of Life Is Based on Heritable Information in the Form of DNA
Chromosomes contain most of a cell’s genetic material in the form of DNA (deoxyribonucleic acid)
DNA is the substance of genes
Genes are the units of inheritance that transmit information from parents to offspring
The ability of cells to divide is the basis of all reproduction, growth, and repair of multicellular organisms

22. DNA bears the blueprint of life
Copyright © 2011 Pearson Education, Inc.

23. 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

24. Theme: Feedback Mechanisms Regulate Biological Systems
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
Positive feedback means that as more of a product accumulates, the process that creates it speeds up and more of the product is produced

25. A Negative feedback B D Excess D blocks a step. D D C D
Enzyme 1 B D
Enzyme 2
Excess D blocks a step. D D C
Enzyme 3
Figure 1.13 Regulation by feedback mechanisms. D
(a) Negative feedback

26. Which of the following examples would represent negative feedback?
As carbon dioxide levels rise in the blood of a mammal, the rate of breathing increases, leading to a decrease in blood levels of carbon dioxide.
As global temperatures rise, more ice melts, leading to greater planetary absorption of sunlight and additional temperature increase.
The speed of a racehorse decreases after running a mile.
The metabolic rate and energy consumption of grizzly bears decrease during hibernation.
Frog eggs hatch after 5 days of development at 28C but after 10 days of development at 23 C.
Answer: a
All of the answers relate to a measurement of a rate. Answers c and d simply show a change in rate as the physiology changes in a individual but are incorrect because there is no feedback. Answer e is incorrect because it simply mentions a difference in development rates at different temperatures. Answer b is incorrect because it shows positive feedback. Answer a is correct because it shows that when one factor (carbon dioxide concentration) rises, a second factor (breathing rate) increases and leads to a reduction in the first factor.

27. Excess Z stimulates a step. Z Y ZW
Enzyme 4 X
Positive feedback 
Enzyme 5
Excess Z stimulates a step. Z Y Z Z
Enzyme 6
Figure 1.13 Regulation by feedback mechanisms. Z
(b) Positive feedback

28. Unity and Diversity of Life
Imagine that you have just discovered a new multicellular but microscopic organism that swims in ponds. You see that it is propelled by cilia on the outside of the organism. What can you say about the evolutionary relationships of this organism?
The presence of cilia shows that it is more closely related to Paramecium than to humans.
The presence of cilia shows that it shares a common ancestor with Paramecium and humans.
It is probably closely related to pond algae.
It is probably most closely related to prokaryotes.
The presence of cilia demonstrates the diversity, but not the unity, of life.
Answer: b
It can seem contradictory to students that “evolution can account for both the unity and diversity of life,” but this is an important concept for them to understand. Organisms share traits that they have inherited from a common ancestor (the unity of life) but differ in traits if natural selection, or perhaps genetic drift, leads to change (the diversity of life). Cilia occur in both Paramecium and humans and, most notably, have the same internal structure. This pattern shows that they have a common ancestor (i.e., answer b is correct) but the differences between Paramecium and humans show they have diverged over evolutionary time. The mere presence of cilia cannot help us decide what the new organism is closely related to (either Paramecium as in answer a, pond algae as in answer c, or prokaryotes as in answer d). Answer e is incorrect because the presence of cilia shows the unity not the diversity of life.

29. Evolution, the Overarching Theme of Biology
Evolution makes sense of everything we know about biology
Organisms are modified descendants of common ancestors
Evolution explains patterns of unity and diversity in living organisms
Similar traits among organisms are explained by descent from common ancestors
Differences among organisms are explained by the accumulation of heritable changes

30. Theories in Science
People who characterize evolution as “just a theory” show that they
know the difference between a hypothesis and a theory.
do not understand that “theory” in science is a broad, overarching concept that explains a variety of observations and instead think scientists use the term “theory” as a synonym for “hypothesis.”
understand how science accumulates information about the nature of the natural world.
understand how to develop scientific experiments.
Answer: b
The term “theory” is important for students to understand, especially in the context of criticism of evolutionary theory by creationists. In everyday language, “theory” and “hypothesis” are used interchangeably. In science, however, “theory” refers to a conceptual construct with a great deal of supporting evidence. Other theories in science are cell theory, theory of gravitation, and Einstein’s theory of general relativity.

31. Classifying the Diversity of Life
Approximately 1.8 million species have been identified and named to date, and thousands more are identified each year
Estimates of the total number of species that actually exist range from 10 million to over 100 million
Taxonomy is the branch of biology that names and classifies species into groups of increasing breadth
Domains, followed by kingdoms, are the broadest units of classification

32. Ursus americanus (American black bear)
Figure 1.14
Species
Genus
Family
Order
Class
Phylum
Kingdom
Domain
Ursus americanus (American black bear)
Ursus
Ursidae
Carnivora
Mammalia
Chordata
Figure 1.14 Classifying life.
Animalia
Eukarya

33. (a) Domain Bacteria (b) Domain Archaea (c) Domain Eukarya 2 m 2 m
Figure 1.15
(a) Domain Bacteria
(b) Domain Archaea
2 m
2 m
(c) Domain Eukarya
Kingdom Animalia
100 m
Kingdom Plantae
Figure 1.15 The three domains of life.
Protists
Kingdom Fungi

34. Unity in the Diversity of Life
DNA is the universal genetic language common to all organisms
Unity in the Diversity of Life
15 m
5 m
Cilia of Paramecium
Cilia of windpipe cells
0.1 m
Cross section of a cilium, as viewed with an electron microscope

35. 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 is the mechanism behind “descent with modification”
Darwin’s theory explained the duality of unity and diversity

36. Darwin observed that
Individuals in a population vary in their traits, many of which are heritable
More offspring are produced than survive, and competition is inevitable
Species generally suit their environment
Individuals that are best suited to their environment are more likely to survive and reproduce
Over time, more individuals in a population will have the advantageous traits
Evolution occurs as the unequal reproductive success of individuals

37. Explain what could “evolve” from here??????1
Population with varied inherited traits 2
Elimination of individuals with certain traits 3
Reproduction of survivors 4
Increasing frequency of traits that enhance survival and reproductive success
Figure 1.20 Natural selection.

38. Cactus-flower- eaters
Green warbler finch Certhidea olivacea
Warbler finches
Insect-eaters
COMMON ANCESTOR
Gray warbler finch Certhidea fusca
Sharp-beaked ground finch Geospiza difficilis
Seed-eater
Vegetarian finch Platyspiza crassirostris
Bud-eater
Mangrove finch Cactospiza heliobates
Woodpecker finch Cactospiza pallida
Tree finches
Insect-eaters
Medium tree finch Camarhynchus pauper
Large tree finch Camarhynchus psittacula
Small tree finch Camarhynchus parvulus
Large cactus ground finch Geospiza conirostris
Cactus-flower- eaters
Cactus ground finch Geospiza scandens
Figure 1.22 Descent with modification: adaptive radiation of finches on the Galápagos Islands.
Ground finches
Seed-eaters
Small ground finch Geospiza fuliginosa
Medium ground finch Geospiza fortis
Large ground finch Geospiza magnirostris

39. Concept 1.3: 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

40. Types of Data
Data are recorded observations or items of information; these fall into two categories
Qualitative data, or descriptions rather than measurements
For example, Jane Goodall’s observations of chimpanzee behavior
Quantitative data, or recorded measurements, which are sometimes organized into tables and graphs

41. Forming and Testing Hypotheses
Observations
Observations and inductive reasoning can lead us to ask questions and propose hypothetical explanations called hypotheses
Question
Hypothesis #1:
Dead batteries
Hypothesis #2:
Burnt-out bulb
A hypothesis is a tentative answer to a well-framed question
A scientific hypothesis leads to predictions that can be tested by observation or experimentation
Prediction:
Replacing batteries will fix problem
Prediction:
Replacing bulb will fix problem
Test of prediction
Test of prediction
Test falsifies hypothesis
Test does not falsify hypothesis

42. Experimental Controls and Repeatability
A controlled experiment compares an experimental group (the artificial kingsnakes) with a control group (the artificial brown snakes)
Ideally, only the variable of interest (the effect of coloration on the behavior of predators) differs between the control and experimental groups
A controlled experiment means that control groups are used to cancel the effects of unwanted variables
A controlled experiment does not mean that all unwanted variables are kept constant
In science, observations and experimental results must be repeatable

43. Science, Technology, and Society
Which of the following is an activity that would not be classified as science or technology?
development of methods to insert human genes into pig embryos
measurement of the flavor and ripening speed of tomatoes that have had different flavor-enhancing genes inserted into their genetic material
investigation of the allergic effect of peanut genes inserted into tomatoes when the tomatoes are eaten by people allergic to peanuts
discussion of whether government-granting agencies should support research into treatment of Parkinson's disease with products from human fetal cells
comparison of the growth rates of different strains of wheat grown at different temperatures
Answer: d
An important idea for students to grasp is the difference between the acquisition of scientific knowledge and social decisions about scientific investigations. Answers a, b, c, and e are strictly scientific or technological investigations. Answer d involves societal decision making as to whether certain scientific investigations should be pursued. A follow-up activity to this question could be to ask students to write other answers that would correctly match the stem.