UNIT VChapter 18

Classification

IV. ClassificationA. Finding Order in Diversity

1. Why Classify?

a. 1.5 million species named. 2 to 100 million species yet to be discovered

b. Need to organize and group according to biological significance

2. Scientific namesScientific names- developed to avoid confusion of common names

a. Binomial nomenclatureBinomial nomenclature- developed by Carolus Linnaeus

1). Each species given two-part scientific name

Ursus arctosUrsus arctos

genusgenus speciesspecies

2). Name is descriptive (usually Latin)

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1. Washtulbbia circularis2. Bluebottlia buzztilentia3. Phattfacia stupenda4. Tigerlillia terribilis5. Plumbunnia nutritiosa6. Manypeeplia upsidownia7. Guittara pensilis8. Pollybirdia singularis

B. Linnaeus’s System of Classification (taxonomytaxonomy- science of classifying and naming organisms)

a. SpeciesSpecies- most specific group. Can reproduce among themselves and produce fertile offspringb. GenusGenus- group of closely related species. Share many characteristicsc. FamilyFamily- group of related genusd. OrderOrder- broad taxonomic group composed of similar familiese. ClassClass- Composed of similar ordersf. PhylumPhylum- made up of several different classes that share important characteristics

g. KingdomKingdom- largest and most inclusive category

C. Modern Evolutionary Classification1. Problems with traditional classification- relied on body structure comparisons. Problems arise due to convergent evolution. (eg. Barnacle and Limpet)

Classifying species based on their anatomy sometimes posed problems for taxonomists. Sometimes due to convergent evolution, organisms that are quite different from each other evolve similar body structures.

2. Evolutionary classification- organisms now grouped into categories that represent lines of evolutionary descent (not just physical similarities)

3. CladogramsCladograms- shows evolutionary relationships among group of organisms (family tree)

4. Similarities in DNA and RNA- look at similarities of genes between organisms

Traditionally, African vultures (top) and American vultures (center) were classified together in the falcon family. But DNA analysis has revealed that American vultures are actually more closely related to storks (bottom)

D. Kingdoms and Domains1. Tree of LifeTree of Life evolves- from original two Kingdoms (Plant and Animal) there are now 6 Kingdoms

2. Three Domain SystemThree Domain System –recent molecular analysis has given rise to new taxonomic category- DomainDomain (3 Domains)

a. Domain BacteriaDomain Bacteria- unicellular prokaryotes with thick cell walls. Includes Kingdom EubacteriaKingdom Eubacteria

b. Domain ArchaeaDomain Archaea- unicellular prokaryotes with cells walls. Live in extreme environments. Includes Kingdom Archaebacteria (no O2)Kingdom Archaebacteria (no O2)

c. Domain EukaryaDomain Eukarya- Includes all organisms with nucleus. Includes 4 Kingdoms: Kingdom Kingdom Protista, Kingdom Fungi, Kingdom Plantae, Protista, Kingdom Fungi, Kingdom Plantae, Kingdom AnimaliaKingdom Animalia

V. How to Classify OrganismsA. Identification KeysIdentification Keys- an aid biologists have developed to identify unknown organisms

1. Requires that you know something about organism- skeletal structure, segmentation, symmetry, etc.2. Dichotomous keyDichotomous key- most common type of key

a. Gives two choices (opposite statements)b. Choose best answerc. Led to further choices that narrow selectiond. Eventually identify organism

B. Different keys developed for different purposes

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Chapter 18

Classification

Biologists use a classification system to name and group organisms because organisms are

a. going extinct.

b. very diverse.

c. all exactly alike.

d. too numerous to count.

Biologists use a classification system to name and group organisms because organisms are

a. going extinct.

b. very diverse.

c. all exactly alike.

d. too numerous to count.

Scientists assign to each organism a universally accepted name in the discipline known as

a. traditional classification.

b. diversity.

c. taxonomy.

d. cladistics.

Scientists assign to each organism a universally accepted name in the discipline known as

a. traditional classification.

b. diversity.

c. taxonomy.

d. cladistics.

In taxonomy, a group at any level of organization is referred to as a

a. category.

b. binomial.

c. taxon.

d. system.

In taxonomy, a group at any level of organization is referred to as a

a. category.

b. binomial.

c. taxon.

d. system.

Scientists have identified and named

a. all living species.

b. all living and extinct species.

c. all extinct species.

d. a fraction of all species.

Scientists have identified and named

a. all living species.

b. all living and extinct species.

c. all extinct species.

d. a fraction of all species.

In a species name, which of the terms is capitalized?

a. the first term

b. the second term

c. both terms

d. neither term

In a species name, which of the terms is capitalized?

a. the first term

b. the second term

c. both terms

d. neither term

The baboons Papio annubis and Papio cynocephalus do NOT belong to the same

a. class.

b. family.

c. genus.

d. species.

The baboons Papio annubis and Papio cynocephalus do NOT belong to the same

a. class.

b. family.

c. genus.

d. species.

How do binomial, or two-part, names compare with early scientific names?

a. They are longer.

b. They are shorter.

c. They are completely descriptive.

d. They are in English.

How do binomial, or two-part, names compare with early scientific names?

a. They are longer.

b. They are shorter.

c. They are completely descriptive.

d. They are in English.

The second part of a scientific name is unique to each

a. order in a class.

b. family in an order.

c. genus in a family.

d. species in a genus.

The second part of a scientific name is unique to each

a. order in a class.

b. family in an order.

c. genus in a family.

d. species in a genus.

The second part of a scientific name is often

a. a Latinized description of a trait.

b. the same as for other members of the same genus.

c. capitalized if it derives from a proper name.

d. different in different locales.

The second part of a scientific name is often

a. a Latinized description of a trait.

b. the same as for other members of the same genus.

c. capitalized if it derives from a proper name.

d. different in different locales.

A genus is composed of a number of related

a. kingdoms.

b. phyla.

c. orders.

d. species.

A genus is composed of a number of related

a. kingdoms.

b. phyla.

c. orders.

d. species.

Linnaeus recognized two kingdoms—

a. bacteria and animals.

b. plants and fungi.

c. plants and animals.

d. protists and animals.

Linnaeus recognized two kingdoms—

a. bacteria and animals.

b. plants and fungi.

c. plants and animals.

d. protists and animals.

The most general and largest category in Linnaeus's system is

a. the phylum.

b. the kingdom.

c. the genus.

d. the species.

The most general and largest category in Linnaeus's system is

a. the phylum.

b. the kingdom.

c. the genus.

d. the species.

Traditional classifications tend to take into account only

a. extinct organisms.

b. RNA similarities.

c. DNA similarities.

d. general similarities.

Traditional classifications tend to take into account only

a. extinct organisms.

b. RNA similarities.

c. DNA similarities.

d. general similarities.

Some similarities between distantly related organisms have been produced by

a. convergent evolution.

b. molecular clocks.

c. mutations.

d. reclassification.

Some similarities between distantly related organisms have been produced by

a. convergent evolution.

b. molecular clocks.

c. mutations.

d. reclassification.

Similar genes are evidence of

a. the unrelatedness of species.

b. mutations.

c. common ancestry.

d. different anatomy.

Similar genes are evidence of

a. the unrelatedness of species.

b. mutations.

c. common ancestry.

d. different anatomy.

What does the presence of homologous genes in very dissimilar organisms imply?

a. The genes evolved according to different selection pressures.

b. The organisms share a common ancestor.

c. The organisms do not share a common ancestor.

d. The genes became identical through mutation.

What does the presence of homologous genes in very dissimilar organisms imply?

a. The genes evolved according to different selection pressures.

b. The organisms share a common ancestor.

c. The organisms do not share a common ancestor.

d. The genes became identical through mutation.

The kingdoms Protista, Plantae, Fungi, and Animalia contain only

a. multicellular organisms.

b. photosynthetic organisms.

c. eukaryotes.

d. prokaryotes.

The kingdoms Protista, Plantae, Fungi, and Animalia contain only

a. multicellular organisms.

b. photosynthetic organisms.

c. eukaryotes.

d. prokaryotes.

Which kingdom contains saprobes with cell walls of chitin?

a. Protista.

b. Fungi.

c. Plantae.

d. Animalia.

Which kingdom contains saprobes with cell walls of chitin?

a. Protista.

b. Fungi.

c. Plantae.

d. Animalia.

Which of the six kingdoms now in use was once grouped with plants?

a. Animalia

b. Eubacteria

c. Fungi

d. Protista

Which of the six kingdoms now in use was once grouped with plants?

a. Animalia

b. Eubacteria

c. Fungi

d. Protista

The domain that includes the kingdom Eubacteria is

a. Archaea.

b. Bacteria.

c. Eukarya.

d. Fungi.

The domain that includes the kingdom Eubacteria is

a. Archaea.

b. Bacteria.

c. Eukarya.

d. Fungi.

The domain that contains unicellular organisms that live in extreme environments is

a. Eubacteria.

b. Eukarya.

c. Archaea.

d. Bacteria.

The domain that contains unicellular organisms that live in extreme environments is

a. Eubacteria.

b. Eukarya.

c. Archaea.

d. Bacteria.

The two domains composed of only unicellular organisms are

a. Eubacteria and Archaea.

b. Eukarya and Bacteria.

c. Archaea and Bacteria.

d. Archaea and Eukarya.

The two domains composed of only unicellular organisms are

a. Eubacteria and Archaea.

b. Eukarya and Bacteria.

c. Archaea and Bacteria.

d. Archaea and Eukarya.

The three-domain system acknowledges fundamental differences between two groups of

a. prokaryotes.

b. eukaryotes.

c. protists.

d. multicellular organisms.

The three-domain system acknowledges fundamental differences between two groups of

a. prokaryotes.

b. eukaryotes.

c. protists.

d. multicellular organisms.