1. Outline 15-3 B: Evidence of Evolution
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Evidence of Evolution

2. I. Fossils 1. Provides a record of past life
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I. Fossils
A. A fossil is the preserved or mineralized remains (bone, tooth, or shell) or imprint of an organism that lived in the past.
1. Provides a record of past life
2. Change over time (evolution) can be seen in the fossil record
3. Fossils found in older rocks are different than those found in newer rocks
4. There are many examples of transitional fossils that show intermediates stages
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3. B. Fossil Examples of Evolution
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B. Fossil Examples of Evolution
1. Whale Evolution
a. Thought to have evolved from 4-legged ungulates (animals with hoofs)
b. Many intermediate fossils are known which show the gradual change over time
2. Horse Evolution
a.Thought to have evolved from smaller non-hoofed animals
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4. Whale Evolution
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5. 12/4/2018
Horse Evolution

6. II. Anatomy & Development
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II. Anatomy & Development
A. Comparisons of anatomy (structures) between organisms can reveal similarities even when functions are different
1. Vestigial Organs
a. Parts that are reduced in size and have little or no function
b. Examples: Wings on flightless birds, miniature leg bones in some whales & snakes, tailbones in humans
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7. Vestigial Organs
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Tail bones in humans
Hip bones in whales

8. 2. Homologous structures
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2. Homologous structures
a. Structures that look similar in different organisms but may have different functions
b. They form in the same way during embryological development
c. Used as evidence for a common ancestor
d. Examples:
 Forelimbs of vertebrates contain the same kinds of bones
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9. Homologous Structures
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10. Homologous Structures
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11. a. Structures that have similar functions but different structures
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3. Analogous structures
a. Structures that have similar functions but different structures
b. They do not form in the same way embryologically
c. Not taken to be evidence for a common ancestor
d. Result of living in similar habitats
e. Called convergent evolution
f. Examples:
 Wings of birds & insects
 Shapes of dolphins & sharks
 Marsupial forms of other mammals
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12. Analogous Structures & Convergent Evolution
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Homologous Structures – form from same parts in embryos
Analogous Structures - due to similar habitats but composed of different parts

13. Convergent Evolution of Mammals
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14. a. The study of organisms as they develop before birth
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4. Embryology
a. The study of organisms as they develop before birth
b. Evolutionary history can be seen in the development of embryos
c. Examples:
 Embryos of vertebrates:
 Each have a:
 tail
 buds that become limbs  pharyngeal gill slits
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15. 12/4/2018

16. Which is Which? Tortoise Chick Rabbit Fish Human Salamander
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Which is Which?
Tortoise
Chick
Rabbit
Fish
Human
Salamander
This is a blank box

17. This is a blank box Which is Which? Tortoise Chick Rabbit Fish Human
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Which is Which?
Tortoise
Chick
Rabbit
Fish
Human
Salamander
This is a blank box

18. 12/4/2018
Which is Which?
Tortoise
Chick
Rabbit
Fish
Human
Salamander

19. III. Geographic Distribution of Living Species
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A. Darwin decided all of the Galapagos finches could have descended from a common ancestor from the mainland
1. Each islands’ birds evolved in different ways due to different habitats
B. Species living on different continents had descended from different ancestors.
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C. Animals on different continents could be exposed to similar ecological conditions & evolve in similar ways
1. Thus, animals that were different from each other initially could evolve certain features in common
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21. Biogeography
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Different animals evolve in similar ways due to similar habitats

22. IV. Biological Molecules as Evidence
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IV. Biological Molecules as Evidence
A. Proteins
1. Comparisons of amino acid sequences of proteins common to many species shows a pattern:
a. Species that share a more recent common ancestor have fewer amino acid differences
b. Those more distantly related have more changes
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23. 1. DNA changes cause changes in amino acids
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B. Nucleic Acids
1. DNA changes cause changes in amino acids
2. Can compare the nucleotide sequences of species and count number of changes
3. More changes are taken to indicate that species diverged from each other longer ago
4. Scientists create phylogenetic trees from these data
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24. Phylogenetic tree
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