Evidence of Evolution Background



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For each animal, indicate what type of movement each limb is responsible for.


Animal

Primary Functions

Human

Using tools, picking up and holding objects

Whale




Cat




Bat




Bird




Crocodile





Compare the skeletal structure of each limb to the human arm. Relate the differences you see in form to the differences in function.


Animal

Comparison to Human Arm in Form

Comparison to Human Arm in Function

Whale

Whale has a much shorter and thicker humerus, radius, and ulna. Much longer metacarpals. Thumb has been shortened to a stub.

The whale fin needs to be longer to help in movement through water. Thumbs are not necessary as the fins are not used for grasping.

Cat







Bat







Bird







Crocodile








Comparative Anatomy – Analogous Structures

Compare the anatomy of the butterfly and bird.

1. What is the function of each of these structures?



2. How are they different in form? Give specific differences.

Comparative Anatomy – Vestigial Structures

Compare the overall body structure of the cave fish and the minnow below.


1. What is the biggest, most obvious difference between the body structures of these two fish?

2. Assume the two fish came from the same original ancestor. Why might the cave fish have evolved without eyesight?


3. What kind of sensory adaptation would you hypothesize the cave fish has to allow it to navigate in a cave, including catching and eating food?

You have now studied three different types of anatomical structures:


  • Homologous structures show individual variations on a common anatomical theme. These are seen in organisms that are closely related.

1. Give an example of a homologous structure from this activity: ________________________




  • Analogous structures have very different anatomies but similar functions. These are seen in organisms that are not necessarily closely related, but live in similar environments and have similar adaptations.

2. Give an example of an analogous structure from this activity: ________________________




  • Vestigial structures are anatomical remnants that were important in the organism’s ancestors, but are no longer used in the same way.

3. Give an example of a vestigial structure from this activity: ___________________________


4. Below are some vestigial structures found in humans. For each, hypothesize what its

function may have been.




Structure

Possible function?

Wisdom teeth




Appendix




Muscles for moving the ear




Body hair




Little toe




Tailbone




5. How are vestigial structures an example of evidence of evolution?



Molecular Biology

Cytochrome c is a protein found in mitochondria. It is used in the study of evolutionary relationships because most animals have this protein. Cytochrome c is made of 104 amino acids joined together. Below is a list of the amino acids in part of a cytochrome protein molecule for 9 different animals. Any sequences exactly the same for all animals have been skipped.


For each non-human animal, take a highlighter and mark any amino acids that are different than the human sequence. When you finish, record how many differences you found in the table below.





42

43

44

46

47

49

50

53

54

55

56

57

58

60

61

62

63

64

65

66

100

101

102

103

104

Human

Q

A

P

Y

S

T

A

K

N

K

G

I

I

G

E

D

T

L

M

E

K

A

T

N

E

Chicken

Q

A

E

F

S

T

D

K

N

K

G

I

T

K

E

E

T

L

M

E

K

A

T

N

E

Horse

Q

A

P

F

T

T

D

K

N

K

G

I

T

G

E

D

T

L

M

E

D

A

T

S

K

Tuna

Q

A

E

Y

S

T

D

K

S

K

G

I

V

N

N

D

T

L

M

E

S

A

T

S

-

Frog

Q

A

A

F

S

T

D

K

N

K

G

I

T

G

E

D

T

L

M

E

S

A

C

S

K

Shark

Q

A

Q

F

S

T

D

K

S

K

G

I

T

Q

Q

E

T

L

R

I

K

T

A

A

S

Turtle

Q

A

E

F

S

T

E

K

N

K

G

I

T

G

E

E

T

L

M

E

D

A

T

S

K

Monkey

Q

A

P

Y

S

T

A

K

N

K

G

I

T

G

E

D

T

L

M

E

K

A

T

N

E

Rabbit

Q

A

V

F

S

T

D

K

N

K

G

I

T

G

E

D

T

L

M

E

K

A

T

N

E



Animal

Number of Amino Acid Differences Compared to Human Cytochrome C

Animal

Number of Amino Acid Differences Compared to Human Cytochrome C

Horse




Shark




Chicken




Turtle




Tuna




Monkey




Frog




Rabbit





Molecular Biology – Summary Questions
1. Based on the Cytochrome C data, which organism is most closely related to humans?

2. Do any of the organisms have the same number of differences from human Cytochrome C? In situations like this, how would you decide which is more closely related to humans?



Conclusion
1. Charles Darwin published his book On the Origin of Species in 1859. Of the different types of evidence that you have examined, which do you think he relied upon the most, and why?

2. Given the amount of research and evidence available on evolution, why is it classified as a theory?




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