Evidence of Evolution

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9- I ca

n id

entify

the fi

ve

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f evid

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r evolu

tion

• Evidence for evolution came through fossils, biogeography, embryology, anatomy, and biochemistry

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10- I ca

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xp

lain

how

fossils

pro

vid

e e

vid

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r evolu

tion

• Fossils: the remains and traces of past life or any other direct evidence of past life– Can be studied for information on environment

of the time, the age of the fossil– Relative age of fossils was determined by where

they were located in the layers of rock• The oldest fossils were on the bottom

– Some can consist of hard parts of organisms• Shells• Bones• Teeth

– Soft parts can be preserved based off of how the sample was preserved

– Trace fossils can be preserved• Trails• Footprints• Worm casts• droppings

Example: Whale

Target #11- I can explain the purpose of a transitional species

• Transitional species– Fossils that serve as links

between groups– Example: Archaeopteryx• Lived 165 million years ago• An intermediate between

reptiles and birds– Had reptile-like features:

jaws, teeth, long and jointed tail

– Had bird-like features: feathers and wings

– Other transitional groups• Fish amphibeans reptiles

Exam

ple

- Te

traphods

Target #12- I can explain how biogeography provides evidence for the theory of evolution

• Biogeography: the study of the range and distribution of plants and animals in different places throughout the world in comparison to the ancestors– Organisms evolve in one locale

and then spread to accessible regions

– A different mix of plants and animals will be present whenever geography separates continents, islands, seas, etc.• Examples

– marsupials in Australia– Lemurs in Madagasgar– Mesosaurus in S.America &

Africa

Example- Lemurs

Example- Marsupials

Target #13- I can explain how embryology provides evidence for evolution

• The homology shared by vertebrates extends to their embryology– All vertebrates have a

postanal tail and exhibit paired pharyngeal pouches• In fish and amphibians, those

pouches develop into gills• In humans they develop into

various components of the neck and inner ear

• Translation since both fish, amphibians, and humans have pharyngeal pouches, fish & amphibians were the common ancestor to all vertebrates

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14- I ca

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xp

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how

an

ato

my p

rovid

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vid

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evolu

tion

• Anatomy– Homologous structures: features that are

similar in structure but appear in different organisms and have different functions• Provides more evidence for the concept of a

common ancestor among all organisms• Ex: forelimbs of vertebrate animals

– Analogous Structures: structures that perform a similar function but are not similar in origin• Ex: wings of insects and birds

– Vestigial structures: remnants of organs or structures that had a function in an early ancestor• Ex: snakes have pelvic bones and limbs but do

not walk• Ex: human have an appendix that is believed to

have been used to process raw meat and plants• Ex: hind limb bones exist in animals like baleen

whales and snakes

Homlogous Structures

Analogous Structures

Example- Vestigial

Structures

Target #15- I can explain the commonalities of organism through their biochemical connections

• Almost all organisms use the same basic biochemical molecules– Includes DNA, ATP, and other

enzymes– Organisms use the same DNA

triplet code for the same 20 amino acids in their proteins

• Humans share a large number of genes with much simpler organisms– Life’s diversity has come about

by only a slight difference in many of the same genes and regulatory genes often found in introns and other regions of the genome

Targ

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15

- con

t.• The more similar the DNA sequences are

between organisms, generally the more closely related the organisms are– Example comparison:• Humans and chimpanzees are about

97% similar– Example protein:• Cytochrome C used for the transport of

materials across the plasma membrane in all organisms– Humans vs. monkeys: 1 amino acid

difference– Humans vs. ducks: 11 amino acid difference– Humans vs. yeast: 51 amino acid difference

– Data is consistent with anatomical similarities of the organisms and their relation to each other

Analyzing Data