Unit 6 - Evidence for Evolution

Question 1

Fossil Record

Answer 1

Advantage: clear tangible evidence
Disadvantage: few organisms fossilized

Question 2

Homologous Structures

Answer 2

-Similar structures that come from the same ancestors that are modified for different purposes
-Evidence of divergent evolution
-Ex. Both humans and cows have similar forearm bones, but we can turn ours and they cannot for stability

Question 3

Analogous Structures

Answer 3

-Different structures used for a similar purpose
-Evidence of convergent evolution
-Ex. Different plants have different structures that kill bugs, like the venus flytrap and the one that drowns them. Different methods, same purpose

Question 4

Vestigial Structures

Answer 4

• Structures that are no longer being utilized due to changes in environment/niche
• Structure gets smaller over time because it is insignificant
• Ex. Snakes used to have legs, and they still have tiny leg bones inside of their body, but they’re not being used anymore

Question 5

Molecular Clock Hypothesis

Answer 5

Assumes that mutations occur at a regular rate, meaning they’re not entirely random (not very stable hypothesis)

Question 6

Embryological

Answer 6

-The longer two species resemble each other in embryonic stages, and the closer the time is for development, the more likely they are closely related
-Ex. Chimps and humans are indiscernible from each other in utero until the third trimester, proving that they are closely, and recently, related

Question 7

Genetic

Answer 7

Certain proteins can be used to determine whether species are closely related or not based on how many they share in common