Evidence for Evolution

Concept MapSection 15-3

includes

Evidence of Evolution

Physical remains of organisms

Common ancestral species Similar genes Similar genes

which is composed of which indicates which implies which implies

The fossil recordGeographic

distribution of living species

Homologous body structures

Similaritiesin early

development

Fossils

Relative Dating

Can determine

Is performed by

Drawbacks

Absolute Dating

Comparing Relative and Absolute Dating of Fossils

Section 17-1

Compare/Contrast Table

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Imprecision and limitations of age data

Difficulty of radioassay laboratory methods

Comparing depth of a fossil’s source stratum to the position of a reference fossil or rock

Determining the relative amounts of a radioactive isotope and nonradioactive isotope in a specimen

Age of fossil with respect to another rock or fossil (that is, older or younger)

Age of a fossil in years

Water carries small rock particles to lakes and seas.

Dead organisms are buried by layers of sediment, which forms new rock.

The preserved remains may later be discovered and studied.

Section 17-1

Figure 17-2 Formation of a Fossil

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Beaver

NORTH AMERICA

Muskrat

Capybara SOUTH AMERICA

Coypu

Geographic Distributionof Living SpeciesSection 15-3

Beaver

Muskrat

Beaver andMuskrat

Coypu

Capybara

Coypu andCapybara

GEOGRAPHIC DISTRIBUTION

• Example: Many pouched mammals (marsupials) in Australia • Few placental mammals

( deer, squirrels)

SIMILARITIES IN STRUCTURE

• Homologous structures

Turtle Alligator Bird Mammals

Typical primitive fish

Homologous Body Structures

Section 15-3

VESTIGIAL STRUCTURES

SIMILARITIES IN DEVELOPMENT

• Similar development

in embryos

The Process of Speciation

A.Isolating Mechanisms1. Behavioral Isolation2. Geographic Isolation3. Temporal Isolation

B.Testing Natural Selection in Nature1. Variation2. Natural Selection3. Rapid Evolution

Section 16-3

results from

which include

produced by produced byproduced by

which result in

which result in

Reproductive Isolation

Isolating mechanisms

Behavioral isolation Temporal isolationGeographic isolation

Behavioral differences Different mating timesPhysical separation

Independentlyevolving populations

Formation ofnew species

Concept MapEvolution of LifeSection 17-2

Early Earth was hot; atmosphere contained poisonous gases.

Earth cooled and oceans condensed.

Simple organic molecules may have formed in the oceans..

Small sequences of RNA may have formed and replicated.

First prokaryotes may have formed when RNA or DNA was enclosed in microspheres.

Later prokaryotes were photosynthetic and produced oxygen.

An oxygenated atmosphere capped by the ozone layer protected Earth.

First eukaryotes may have been communities of prokaryotes.

Multicellular eukaryotes evolved.

Sexual reproduction increased genetic variability, hastening evolution.

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Section 17-3

Geologic Time Scale with Key Events

Glaciations; mammals increased; humansMammals diversified; grassesAquatic reptiles diversified; flowering plants; mass extinctionDinosaurs diversified; birdsDinosaurs; small mammals; cone-bearing plantsReptiles diversified; seed plants; mass extinctionReptiles; winged insects diversified; coal swampsFishes diversified; land vertebrates (primitive amphibians)Land plants; land animals (arthropods)Aquatic arthropods; mollusks; vertebrates (jawless fishes)Marine invertebrates diversified; most animal phyla evolvedAnaerobic, then photosynthetic prokaryotes; eukaryotes, then multicellular life

Cenozoic

Mesozoic

Paleozoic

PrecambrianTime

QuaternaryTertiaryCretaceousJurassicTriassicPermianCarboniferousDevonianSilurianOrdovicianCambrian

1.8–present65–1.8145–65208–145245–208290–245363–290410–363440–410505–440544–505650–544

Key EventsEra Period Time(millions of years ago)

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Patterns of Evolution

A. Mass ExtinctionsB. Adaptive RadiationC. Convergent EvolutionD. CoevolutionE. Punctuated EquilibriumF. Developmental Genes and Body Plans

Section 17-4

Section Outline

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Section 17-4

Flowchart

that are

can undergo can undergo can undergo can undergo can undergo

in underunderform inin

Species

Unrelated Related

Inter-relationshiops Similar environments

Intense environmental

pressure

Small populations

Different environments

Coevolution Convergent evolution Extinction Punctuated

equilibriumAdaptive radiation

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