table of contents – pages iii

Unit 1: What is Biology?Unit 2: EcologyUnit 3: The Life of a CellUnit 4: GeneticsUnit 5: Change Through TimeUnit 6: Viruses, Bacteria, Protists, and FungiUnit 7: PlantsUnit 8: InvertebratesUnit 9: VertebratesUnit 10: The Human Body

Unit 1: What is Biology?

Chapter 1: Biology: The Study of LifeUnit 2: Ecology Chapter 2: Principles of Ecology Chapter 3: Communities and Biomes Chapter 4: Population Biology Chapter 5: Biological Diversity and ConservationUnit 3: The Life of a Cell Chapter 6: The Chemistry of Life Chapter 7: A View of the Cell Chapter 8: Cellular Transport and the Cell Cycle Chapter 9: Energy in a Cell

Unit 4: Genetics

Chapter 10: Mendel and Meiosis

Chapter 11: DNA and Genes

Chapter 12: Patterns of Heredity and Human Genetics

Chapter 13: Genetic Technology

Unit 5: Change Through Time Chapter 14: The History of Life Chapter 15: The Theory of Evolution Chapter 16: Primate Evolution Chapter 17: Organizing Life’s Diversity

Unit 6: Viruses, Bacteria, Protists, and Fungi

Chapter 18: Viruses and Bacteria

Chapter 19: Protists

Chapter 20: Fungi

Unit 7: Plants

Chapter 21: What Is a Plant?

Chapter 22: The Diversity of Plants

Chapter 23: Plant Structure and Function

Chapter 24: Reproduction in Plants

Unit 8: Invertebrates

Chapter 25: What Is an Animal?

Chapter 26: Sponges, Cnidarians, Flatworms, and

Roundworms

Chapter 27: Mollusks and Segmented Worms

Chapter 28: Arthropods

Chapter 29: Echinoderms and Invertebrate

Chordates

Unit 9: Vertebrates Chapter 30: Fishes and Amphibians

Chapter 31: Reptiles and Birds

Chapter 32: Mammals

Chapter 33: Animal Behavior

Unit 10: The Human Body

Chapter 34: Protection, Support, and Locomotion

Chapter 35: The Digestive and Endocrine Systems

Chapter 36: The Nervous System

Chapter 37: Respiration, Circulation, and Excretion

Chapter 38: Reproduction and Development

Chapter 39: Immunity from Disease

Change Through Time

The History of Life

The Theory of Evolution

Primate Evolution

Organizing Life’s Diversity

Chapter 17 Organizing Life’s Diversity

17.1: Classification

17.1: Section Check

17.2: The Six Kingdoms

17.2: Section Check

Chapter 17 Summary

Chapter 17 Assessment

What You’ll Learn

You will identify and compare various methods of classification.

You will distinguish among six kingdoms of organisms.

• Evaluate the history, purpose, and methods of taxonomy.

Section Objectives:

• Explain the meaning of a scientific name.

• Describe the organization of taxa in a biological classification system.

• Biologists want to better understand organisms so they organize them.

• One tool that they use to do this is classification—the grouping of objects or information based on similarities.

How Classification BeganHow Classification Began

• Biologists who study taxonomy are called taxonomists.

How Classification BeganHow Classification Began• Taxonomy (tak SAH

nuh mee) is the branch of biology that groups and names organisms based on studies of their different characteristics. Click image to view movie.

• He classified all the organisms he knew into two groups: plants and animals.

Aristotle’s systemAristotle’s system

• The Greek philosopher Aristotle (384-322 B.C.) developed the first widely accepted system of biological classification.

• He grouped animals according to various characteristics, including their habitat and physical differences.


• He subdivided plants into three groups, herbs, shrubs, and trees, depending on the size and structure of a plant.

• As time passed, more organisms were discovered and some did not fit easily into Aristotle’s groups, but many centuries passed before Aristotle’s system was replaced.


• According to his system, birds, bats, and flying insects are classified together even though they have little in common besides the ability to fly.

• Linnaeus’s system was based on physical and structural similarities of organisms.

Linnaeus’s system of binomial nomenclatureLinnaeus’s system of binomial nomenclature

• In the late eighteenth century, a Swedish botanist, Carolus Linnaeus (1707-1778), developed a method of grouping organisms that is still used by scientists today.

• As a result, the groupings revealed the relationships of the organisms.

• This way of organizing organisms is the basis of modern classification systems.


• Eventually, some biologists proposed that structural similarities reflect the evolutionary relationships of species.

• In this system, the first word identifies the genus of the organism.


• Modern classification systems use a two-word naming system called binomial nomenclature that Linnaeus developed to identify species.

• A genus (JEE nus) (plural, genera) consists of a group of similar species.

• Thus, the scientific name for each species, referred to as the species name, is a combination of the genus name and specific epithet.


• The second word, which sometimes describes a characteristic of the organism, is called the specific epithet.

Homo sapiens

• Scientific names should be italicized in print and underlined when handwritten.

• Taxonomists are required to use Latin because the language is no longer used in conversation and, therefore, does not change.

• The first letter of the genus name is uppercase, but the first letter of the specific epithet is lowercase.

Passer domesticus

Scientific and common namesScientific and common names

• In addition, it is confusing when a species has more than one common name.

Scientific and common namesScientific and common names• Many organisms have

common names. However, a common name can be misleading. For example, a sea horse is a fish, not a horse.

• Grouping organisms on the basis of their evolutionary relationships makes it easier to understand biological diversity.

Modern ClassificationModern Classification

• Expanding on Linnaeus’s work, today’s taxonomists try to identify the underlying evolutionary relationships of organisms and use the information gathered as a basis for classification.

• For example, biologists study the relationship between birds and dinosaurs within the framework of classification.

• Taxonomists group similar organisms, both living and extinct. Classification provides a framework in which to study the relationships among living and extinct species.

Archaeopteryx

Taxonomy: A frameworkTaxonomy: A framework

Taxonomy: A useful toolTaxonomy: A useful tool

• Classifying organisms can be a useful tool for scientists who work in agriculture, forestry, and medicine.

Taxonomy: A useful toolTaxonomy: A useful tool

• Anyone can learn to identify many organisms using a dichotomous key.

• A key is made up of sets of numbered statements. Each set deals with a single characteristic of an organism, such as leaf shape or arrangement.

Taxonomy and the economyTaxonomy and the economy

• It often happens that the discovery of new sources of lumber, medicines, and energy results from the work of taxonomists.

• The characteristics of a familiar species are frequently similar to those found in a new, related species.

Taxonomy and the economyTaxonomy and the economy

• For example, if a taxonomist knows that a certain species of pine tree contains chemicals that make good disinfectants, it’s possible that another pine species could also contain these useful substances.

How Living Things Are ClassifiedHow Living Things Are Classified

• In any classification system, items are categorized, making them easier to find and discuss.

• Although biologists group organisms, they subdivide the groups on the basis of more specific criteria.

• A group of organisms is called a taxon (plural, taxa).

Taxonomic rankingsTaxonomic rankings

• Organisms are ranked in taxa that range from having very broad characteristics to very specific ones.

• The broader a taxon, the more general its characteristics, and the more species it contains.


• The smallest taxon is species. Organisms that look alike and successfully interbreed belong to the same species.

• The next largest taxon is a genus—a group of similar species that have similar features and are closely related.

• Compare the appearance of a lynx, Lynx rufus, a bobcat, Lynx canadensis, and a mountain lion, Panthera concolor.

Lynx Mountain lionBobcat


Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

Eukarya

Animalia

Chordata

Mammalia

Carnivora

Felidae

Lynx

Lynx rufus

Lynx canadensis

Bobcat Lynx

Question 1

How did Aristotle group organisms such as birds, bats, and insects? (TX Obj 2; 8C)

D. by their homologous structures

C. by their common species

B. by their analogous structures

A. by their common genus

The answer is B. The organisms were grouped together because of their wings, which, in this case, are analogous structures.

Question 2Which taxon contains the fewest species?(TX Obj 2; 8C)

D. phylumC. order B. familyA. genus

The answer is A, genus.

Question 3For which of the following species names does the specific epithet mean “handy?” (TX Obj 2; 8C)

D. Homo habilis

C. Australopithecus anamensis

B. Homo erectus

A. Homo sapiens

The answer is D.

Question 4

What is the difference between “classification” and “taxonomy?” (TX Obj 2; 8C)

AnswerClassification is the grouping of objects or information based on similarities. Taxonomy is the branch of biology that classifies and names organisms based on their different characteristics.

Question 5

What are the two parts that make up binomial nomenclature? (TX Obj 2; 8C)

Answer

Binomial nomenclature comprises a genus name followed by a specific epithet.

Section Objectives

• Explain how cladistics reveals phylogenetic relationships.

• Describe how evolutionary relationships are determined.

• Compare the six kingdoms of organisms.

• Evolutionary relationships are determined on the basis of similarities in structure, breeding behavior, geographical distribution, chromosomes, and biochemistry.

How are evolutionary relationships determined?How are evolutionary relationships determined?

• Structural similarities among species reveal relationships.

Structural similaritiesStructural similarities

• The presence of many shared physical structures implies that species are closely related and may have evolved from a common ancestor.

• For example, plant taxonomists use structural evidence to classify dandelions and

sunflowers in the same family, Asteraceae, because they have similar flower and fruit structures.



• Taxonomists observe and compare features among members of different taxa and use this information to infer their evolutionary history.

• Sometimes, breeding behavior provides important clues to relationships among species.

• For example, two species of frogs, Hyla versicolor and Hyla chrysoscelis, live in the same area and look similar. During the breeding season, however, there is an obvious difference in their mating behavior.

• Scientists concluded that the frogs were two separate species.

Breeding behaviorBreeding behavior

Geographical distributionGeographical distributionCrushing

Bills

Probing Bills

Grasping Bills

Ancestral Species

Parrot Bills

SeedFeedersC

actu

s

Fee

ders

Insect

Feeders

Fruit

Feeders

• These finches probably spread into different niches on the volcanic islands and evolved over time into many distinct species. The fact that they share a common ancestry is supported by their geographical distribution in addition to their genetic similarities.

Geographical distributionGeographical distribution

• Both the number and structure of chromosomes, as seen during mitosis

and meiosis, provide evidence about relationships among species.

Chromosome comparisonsChromosome comparisons

Chromosome comparisonsChromosome comparisons• For example, cauliflower, cabbage, kale, and

broccoli look different but have chromosomes that are almost identical in structure.

Chromosome comparisonsChromosome comparisons

• Therefore, biologists propose that these plants are related.

• Powerful evidence about relationships among species comes from biochemical analyses of organisms.

BiochemistryBiochemistry

• Closely related species have similar DNA sequences and, therefore, similar proteins.

• In general, the more inherited nucleotide sequences that two species share, the more closely related they are.

• The evolutionary history of a species is called its phylogeny (fy LAH juh nee).

Phylogenetic Classification: ModelsPhylogenetic Classification: Models

• A classification system that shows the evolutionary history of species is a phylogenetic classification and reveals the evolutionary relationships of species.

• One biological system of classification that is based on phylogeny is cladistics (kla DIHS tiks).

CladisticsCladistics

• Scientists who use cladistics assume that as groups of organisms diverge and evolve from a common ancestral group, they retain some unique inherited characteristics that taxonomists call derived traits.


Theropods

Allosaurus

Sinornis

Velociraptor

Archaeopteryx

Robin

Light bones 3-toed foot; wishbone

Down feathers

Feathers withshaft, veins,and barbs

Flight feathers;arms as long

as legs

• However, an important difference between cladograms and pedigrees is that,

whereas pedigrees show the direct ancestry of an organism from two parents, cladograms show a probable evolution of a group of organisms from ancestral groups.


• One type of model resembles a fan.

Another type of modelAnother type of model

• Unlike a cladogram, a fanlike model may communicate the time organisms became extinct or the relative number of species in a group.

• A fanlike diagram incorporates fossil information and the knowledge

gained from anatomical, embryological, genetic, and cladistic studies.

Life’s Six KingdomsLife’s Six Kingdoms

• The six kingdoms of organisms are archaebacteria, eubacteria, protists, fungi, plants, and animals.

The Six Kingdoms of OrganismsThe Six Kingdoms of Organisms

• In general, differences in cellular structures and methods of obtaining energy are the two main characteristics that distinguish among the members of the six kingdoms.

• The prokaryotes, organisms with cells that lack distinct nuclei bounded by a membrane, are microscopic and unicellular.

ProkaryotesProkaryotes

• Some are heterotrophs and some are autotrophs.


• In turn, some prokaryotic autotrophs are chemosynthetic, whereas others are photosynthetic.

• There are two kingdoms of prokaryotic organisms: Archaebacteria and Eubacteria.

• There are several hundred species of known archaebacteria and most of them live in extreme environments such as swamps, deep-ocean hydrothermal vents, and seawater evaporating ponds.

• Most of these environments are oxygen-free.



• All of the other prokaryotes, about 5000 species of bacteria, are classified in Kingdom Eubacteria.

• Eubacteria have very strong cell walls and a less complex genetic makeup than found in archaebacteria or eukaryotes.


• They live in most habitats except the extreme ones inhabited by the archaebacteria.

• Although some eubacteria cause diseases, such as strep throat and pneumonia, most bacteria are harmless and many are actually helpful.

Protists: A diverse groupProtists: A diverse group

• Kingdom Protista contains diverse species that share some characteristics.

• A protist is a eukaryote that lacks complex organ systems and lives in moist environments.

Cilia

Oral groove

Gullet

Micronucleus and macronucleus

Contractile vacuole

Anal pore

A Paramecium

Protists: A diverse groupProtists: A diverse group

• Although some protists are unicellular, others are multicellular.

• Some are plantlike autotrophs, some are animal-like heterotrophs, and others are funguslike heterotrophs that produce reproductive structures like those of fungi.

Fungi: Earth’s decomposersFungi: Earth’s decomposers

• Organisms in Kingdom Fungi are heterotrophs that do not move from place to place.

• A fungus is either a unicellular or multicellular eukaryote that absorbs nutrients from organic materials in the environment.

Fungi: Earth’s decomposersFungi: Earth’s decomposers

• There are more than 50,000 known species of fungi.

Plants: Multicellular oxygen producersPlants: Multicellular oxygen producers

• All of the organisms in Kingdom Plantae are multicellular, photosynthetic eukaryotes.

• None moves from place to place.


• A plant’s cells usually contain chloroplasts and have cell walls composed of cellulose.

• Plant cells are organized into tissue that, in turn, are organized into organs and organ systems.

• The oldest plant fossils are more than 400 million years old.

• However, some scientists propose that plants existed on Earth’s landmasses much earlier than these fossils indicate.


• There are more than 250,000 known species of plants.

• Although you may be most familiar with flowering plants, there are many other types of plants, including mosses, ferns, and evergreens.


Animals: Multicellular consumersAnimals: Multicellular consumers

• Animals are multicellular heterotrophs.

• Nearly all are able to move from place to place.

• Animal cells do not have cell walls.

Animals: Multicellular consumersAnimals: Multicellular consumers

• Their cells are organized into tissues that, in turn, are organized into organs and complex organ systems.

• Animals first appeared in the fossil record about 600 million years ago.

Which of the following is NOT a way to determine evolutionary relationships? (TX Obj 2; 8C)

Question 1

D. geographical distribution C. specific epithets B. biochemistryA. chromosome comparisons

The answer is C.

How does a cladogram differ from a pedigree?(TX Obj 2; 8C)

Question 2

AnswerPedigrees show the direct ancestry of an organism from two parents. Cladograms show a probable evolution from an ancestral group.

Using the cladogram, which of the following traits would be a primitive trait? (TX Obj 2; 8C)

Question 3

Theropods

Allosaurus

Sinornis

Velociraptor

Archaeopteryx

Robin


Down feathers



as legs

Question 3

Theropods

Allosaurus

Sinornis

Velociraptor

Archaeopteryx

Robin


Down feathers



as legs

A. down feathers B. arms as long as legs C. light bones D. flight feathers

The answer is C. Primitive traits are traits that evolved very early.

Theropods

Allosaurus

Sinornis

Velociraptor

Archaeopteryx

Robin


Down feathers



as legs

Why do taxonomists use Latin names for classification? (TX Obj 2; 8C)

Question 4

Answer

Latin is no longer used in conversation and, therefore, does not change.

What is the relationship between cladistics and taxonomy? (TX Obj 2; 8C)

Question 5

Answer

Cladistics is one kind of taxonomy that is based on phylogeny.

• Although Aristotle developed the first classification system, Linnaeus laid the foundation for modern classification systems by using structural similarities to organize species and by developing a binomial naming system for species.

Classification

• Scientists use a two-word system called binomial nomenclature to give species scientific names.

• Classification provides an orderly framework in which to study the relationships among living and extinct species.

Classification

• Organisms are classified in a hierarchy of taxa: domain, kingdom, phylum or division, class, order, family, genus, and species.

• Biologists use similarities in body structures, breeding behavior, geographic distribution, chromosomes, and biochemistry to determine evolutionary relationships.

The Six Kingdoms

• Modern classification systems are based on phylogeny—the evolutionary history of a species.

• Kingdoms Archaebacteria and Eubacteria contain only unicellular prokaryotes.

The Six Kingdoms

• Kingdom Protista contains eukaryotes that lack complex organ systems.

• Kingdom Fungi includes heterotrophic eukaryotes that absorb their nutrients.

• Kingdom Plantae includes multicellular eukaryotes that are photosynthetic.

The Six Kingdoms

• Kingdom Animalia includes multicellular, eukaryotic heterotrophs with cells that lack cell walls.

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

Eukarya

Animalia

Chordata

Mammalia

Carnivora

Felidae

Lynx

Lynx rufus

Lynx canadensis

Bobcat Lynx

Question 1

TX Obj 2; 8C

Both organisms are members of the same kingdom, phylum, class, order, family, and genus but belong to different species.

Question 2Which taxon contains the others? (TX Obj 2; 8C)

D. family

C. genus B. class

A. order

The answer is B.

Question 3

Which of the following pairs of terms is NOT related? (TX Obj 2; 8C)

D. Aristotle – evolutionary relationships

C. biology – taxonomy

B. binomial nomenclature – Linnaeus

A. specific epithet – genus

The answer is D.

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

Eukarya

Animalia

Chordata

Mammalia

Carnivora

Felidae

Lynx

Lynx rufus

Lynx canadensis

Bobcat Lynx

Question 4

TX Obj 2; 8C

Bobcats are more closely associated with lynxes as cats than as mammals.

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

Eukarya

Animalia

Chordata

Mammalia

Carnivora

Felidae

Lynx

Lynx rufus

Lynx canadensis

Bobcat Lynx

Question 5What two main characteristics distinguish the members of the six kingdoms? (TX Obj 2; 8C)

AnswerThe two characteristics are differences in cellular structures and methods of obtaining energy.

Question 6Which of the following is NOT true of both the animal and plant kingdoms?(TX Obj 2; 8C)

D. cells contain cell walls C. cells are organized into tissues

B. tissues are organized into organs A. both contain organisms made up of cells

The answer is D.

Question 7

Which of the following describes a fungus? (TX Obj 2; 8C)

D. heterotrophic prokaryote

C. unicellular autotroph

B. unicellular or multicellular heterotroph

A. autotrophic prokaryote

The answer is B, unicellular or multicellular heterotroph.

Question 8

What is a dichotomous key?(TX Obj 2; 8C)

Answer

A dichotomous key is a set of paired statements that can be used to identify organisms.

Question 9

How has DNA-DNA hybridization shown that flamingoes are more closely related to storks than they are to geese?

When DNA from storks and flamingoes was allowed to bond, DNA base pairs matched and the strands bonded more strongly than when DNA from flamingoes and geese was allowed to bond.

FlamingoStork

Question 10

Why do some scientists believe that plants existed on Earth’s landmasses much earlier than fossils indicate?

Answer

Plants do not fossilize as often as organisms that contain hard structures, like bones, which more readily fossilize than soft tissues.

Photo CreditsPhoto Credits

• NOAA

• PhotoDisc

• Mark Steinmetz

• Corbis

• Digital Stock

• Alton Biggs

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table of contents – pages iii

Documents

bacteria chapter

protists chapter

cell chapter

fungi chapter

biomes chapter

amphibians chapter

genes chapter

arthropods chapter