Chapter 1 Scientific Study of Life Cownose rays ©Pete Oxford/Minden Pictures.

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Chapter 1 Scientific Study of Life

Cownose rays ©Pete Oxford/Minden Pictures

Section 1.1

Biology is the scientific study of life.

The Characteristics of Life

Swans: ©Jadranko Markoc/flickr/Getty Images RF; DNA:© SMC Images/The Image Bank/Getty Images

Cells are the basic units of life. Every organism, or living individual, consists of one or more cells.

Cells use DNA to produce proteins.

Section 1.1

How do we know these swans are alive, and this rock is not alive?

Swans: ©Jadranko Markoc/flickr/Getty Images RF; Ecosystem: © Manoj Shah/The Image Bank/Getty Images; DNA:© SMC Images/The Image Bank/Getty Images

Section 1.1

All life shares five characteristics.- Organization

Section 1.1

Figure 1.2

ATOMThe smallest chemicalunit of a type of puresubstance (element).Example: Carbon atom

The Characteristics of LifeLife is organized

Section 1.1 Figure 1.2

MOLECULEA group of joined atoms.Example: DNA

ORGANELLEA membrane-boundedstructure that has a specificfunction within a cell.Example: Chloroplast

CELLThe fundamentalunit of life.Example: Leaf cell

TISSUEA collection of specializedcells that function in acoordinated fashion.Example: Epidermis of leaf

ORGANA structure consistingof tissues organized tointeract and carryout specific functions.Example: Leaf

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Figure 1.2

ORGAN SYSTEMOrgans connectedphysically or chemicallythat function together.Example: Abovegroundpart of a plant

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Figure 1.2

ORGANISMA single living individual.Example: One acacia tree

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Figure 1.2

POPULATIONA group of the same species of organismliving in the same place and time.Example: Multiple acacia trees

Population: ©Gregory G. Dimijian, M.D./Science Source

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Figure 1.2

COMMUNITYAll populations that occupythe same region.Example: All populationsin a savanna

Population: ©Gregory G. Dimijian, M.D./Science Source; Community: ©Daryl Balfour/Gallo Images/Getty Images

Section 1.1

Figure 1.2

ECOSYSTEMThe living and nonlivingcomponents of an area.Example: The savanna

Population: ©Gregory G. Dimijian, M.D./Science Source; Community: ©Daryl Balfour/Gallo Images/Getty Images; Ecosystem: © Manoj Shah/The Image Bank/Getty Images

Section 1.1

Figure 1.2

BIOSPHEREThe global ecosystem;the parts of the planetand its atmospherewhere life is possible.

Population: © Gregory G. Dimijian, M.D./Science Source; Community: ©Daryl Balfour/Gallo Images/Getty Images; Ecosystem: © Manoj Shah/The Image Bank/Getty Images; Biosphere: © Corbis RF

Endothelialcell

Sheet ofendothelialcells

Capillary

EndothelialcellRed blood

Emergent properties arise at each level of biological organization.

The capillary has properties that its components alone lack.

Clicker Question #1

Which of the following statements is false?

A. Organs consist of tissues. B. Populations consist of organisms.C. Molecules consist of cells. D. Organisms consist of atoms. E. Organelles consist of molecules.

Flower: © Doug Sherman/Geofile/RF

Clicker Question #1

Which of the following statements is false?

A. Organs consist of tissues. B. Populations consist of organisms.C. Molecules consist of cells. D. Organisms consist of atoms. E. Organelles consist of molecules.

Clicker Question #2

Which is the best example of emergent properties?

A. Wearing glasses gives you better vision.

B. Welding metal together makes an office building.

C. Wearing clothes keeps you warmer. D. Stacking cups on top of each other makes

a plastic pyramid.E. Tying strings together makes a longer

string.

Clicker Question #2

Which is the best example of emergent properties?

A. Wearing glasses gives you better vision.

B. Welding metal together makes an office building.

C. Wearing clothes keeps you warmer. D. Stacking cups on top of each other makes

a plastic pyramid.E. Tying strings together makes a longer

string.

Section 1.1

All life shares five characteristics.- Organization ✔- Energy use

Section 1.1

The Characteristics of LifeLife requires energy

Producers extract energyand nutrients from thenonliving environment.

Energyfromsunlight

Figure 1.4

Section 1.1

Energyfromsunlight

Heat Consumers obtainenergy and nutrients byeating other organisms.

Figure 1.4

Section 1.1

Energyfromsunlight

Decomposers are consumersthat obtain nutrients from deadorganisms and organic wastes.

HeatHeat

Figure 1.4

Section 1.1

Energyfromsunlight

Heat is lost every time energy is transferred.

Figure 1.4

Section 1.1

All life shares five characteristics.- Organization ✔- Energy use ✔- Maintenance of internal

constancy

Section 1.1

The Characteristics of LifeLife maintains internal constancy

Homeostasis is the process by which a cell or organism maintains equilibrium.

A thermostat is an analogy for how life maintains internal constancy.

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The Characteristics of LifeLife maintains internal constancy

Humans have an internal thermostat that helps maintain temperature homeostasis. This woman shivers and adds clothing when she feels cold.

Figure 1.5Woman shivering © Design Pics/Kristy-Anne Glubish RF; Woman drinking © John Rowley/Getty Images RF

Homeostasis is not just about temperature though. For example, organisms also fluctuate around their optimal nutrient, salt, and water balances.

Section 1.1

All life shares five characteristics.- Organization ✔- Energy use ✔- Maintenance of internal constancy ✔

- Reproduction, growth, and development

Section 1.1

The Characteristics of LifeLife reproduces, grows, and develops

Reproduction is either asexual or sexual.

Figure 1.6Strawberry Plant: © Dorling Kindersley/Getty Images; Swans: ©Jadranko Markoc/flickr/Getty Images RF

Section 1.1

Offspring of asexually reproducing organisms are identical to their single parent.

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Strawberry plants sometimes reproduce asexually. Each of these plantlets is identical to the parent plant.

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Asexual reproduction is a successful strategy in unchanging environments.

Offspring of sexually reproducing organisms receive genetic material from two parents.

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Most plants and animals reproduce sexually. These young swans received genetic material from two parents.

Sexual reproduction is successful in changing environments, since offspring are unlike either parent.

Section 1.1

This plantlet and this swan both started as a single cell and have grown and developed into multicellular organisms.

Clicker Question #3

Which of the following statements is true about reproduction?

A. Sexual reproduction creates genetic variation among organisms.

B. Sexual reproduction is most successful in unchanging environments.

C. Most plants reproduce only asexually. D. Asexual organisms do not actually

reproduce. E. None of these is true.

Clicker Question #3

Which of the following statements is true about reproduction?

A. Sexual reproduction creates genetic variation among organisms.

B. Sexual reproduction is most successful in unchanging environments.

C. Most plants reproduce only asexually. D. Asexual organisms do not actually

reproduce. E. None of these is true.

Section 1.1

All life shares five characteristics.- Organization ✔- Energy use ✔- Maintenance of internal constancy ✔- Reproduction, growth, and development ✔- Evolution

The Characteristics of LifeLife evolves

How is it that so many organisms seem perfectly suited to their environment?

Section 1.1 Figure 1.7Pygmy seahorse © Mark Webster Wwwphoteccouk/Getty Images

This pigmy seahorse blends into the coral habitat where it lives.

Seahorses that blend in best likely survive the longest and reproduce the most.

The Characteristics of LifeLife evolves

Antibiotic-resistant bacteria are most successful when antibiotics are present.

Section 1.1

All life shares five characteristics.- Organization ✔- Energy use ✔- Maintenance of internal constancy ✔

- Reproduction, growth, and development ✔

- Evolution ✔

1.1 Mastering Concepts

What are the roles of natural selection and mutations in evolution?

Section 1.2

The Tree of Life Includes Three Main Branches

Taxonomy is the scientific study of naming and classifying organisms.

Figure 1.9

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Species are broadly categorized into one of three domains.

Figure 1.9

Each domain includes one or more kingdoms.

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Figure 1.9

Domain Bacteria and Domain Archaea are prokaryotic and unicellular.

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Figure 1.9

Organisms in Domain Eukarya have cells with nuclei.

Section 1.2

Figure 1.9

Bee: Courtesy of The National Human Genome Research Institute

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Figure 1.9

Section 1.2

Figure 1.9

Clicker Question #4

How are eukaryotes different from prokaryotes?

A. Eukaryotes are always multicellular.B. Prokaryotic cells never have nuclei.C. Only prokaryotes are autotrophs.D. Only eukaryotes are living organisms.E. None of these distinguish eukaryotes from

prokaryotes.

Clicker Question #4

How are eukaryotes different from prokaryotes?

A. Eukaryotes are always multicellular.B. Prokaryotic cells never have nuclei.C. Only prokaryotes are autotrophs.D. Only eukaryotes are living organisms.E. None of these distinguish eukaryotes from

prokaryotes.

Which kingdoms contain eukaryotic organisms?

Section 1.3

The Scientific Method

Figure 1.10

In general, all scientific inquiry follows a standard process.

Types of Science

Figure 1.11

Scientists test their hypotheses with discovery science or controlled experiments.

Section 1.3

Components of Experiments

Figure 1.11

• Independent variable: what is manipulated (e.g., type of coffee bean)

• Dependent variable: what is measured (e.g., amount of caffeine)

• Standardized variable: held constant for all subjects in an experiment (e.g., mass of beans)

Well-designed experiments include independent, dependent, and standardized variables.

What is the dependent variable in the experiment outlined in this graph?

Clicker Question #5

Figure 1.12

What is the dependent variable in the experiment outlined in this graph?

Clicker Question #5

Figure 1.12

What are the components of scientific inquiry?

Sections 1.3 & 1.4

Scientific Theories Help Explain Observations

Figure 1.13

When Charles Darwin saw the nectar tubes on these orchids he predicted that a moth had an equally long tongue.

He based this prediction on his theory of evolution.

Sections 1.3 & 1.4

Scientific Theories Help Explain Observations

Figure 1.14

Thirty years later, the moth was discovered.

What observations led Darwin and Wallace to predict the existence of a long-tongued moth in Madagascar?

Chapter 1 Scientific Study of Life Cownose rays ©Pete Oxford/Minden Pictures.

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