Question

1. circle the pairing of organisms from model 3 that you predict would have the most divergence in their dna. support your choices with a group discussion about morphology (observable characteristics and structure), ecology, and lifestyles of the animals.

a. whale and human or whale and tuna
b. pig and rhesus monkey or pig and chicken
c. tuna and fly or tuna and chicken
read this!
cytochrome c is a protein that is shared by many organisms due to its vital role in cellular respiration. over time (billions of years) mutations have occurred in the cytochrome c gene that do not affect the function of the cytochrome c protein. these mutations are called neutral mutations. by looking at these mutations scientists can predict when the organisms diverged from a common ancestor and from each other.

1. refer to model 3. write down the number of differences between the amino - acid sequence of cytochrome c in a human and each of the following organisms.

a. tuna
b. whale
c. rhesus monkey
d. chicken
e. pig
f. yeast
g. fly

1. based on the differences in amino - acid sequences, to which organism from the list are humans

a. most closely related to?
b. most distantly related to?

Explanation:

Step1: Analyze DNA divergence in 19a

Whales are mammals, humans are mammals, and tuna are fish. Mammals share more recent common - ancestors among themselves compared to mammals and fish. So whale and tuna likely have more DNA divergence.

Step2: Analyze DNA divergence in 19b

Pigs and rhesus monkeys are both mammals, while pigs are mammals and chickens are birds. Mammals have a closer evolutionary relationship than mammals and birds, so pig and chicken likely have more DNA divergence.

Step3: Analyze DNA divergence in 19c

Tuna are fish, flies are insects, and chickens are birds. Tuna and flies are from very different taxonomic groups compared to tuna and chickens. So tuna and fly likely have more DNA divergence.

Step4: Answer 20

Without Model 3 data, we assume typical values. The number of differences in amino - acid sequences of cytochrome c between human and tuna is around 21, between human and whale is around 10, between human and rhesus monkey is around 1, between human and chicken is around 13, between human and pig is around 10, between human and yeast is around 44, between human and fly is around 29.

Step5: Answer 21a

Based on the above differences, humans are most closely related to rhesus monkey as it has the least number of differences in the amino - acid sequence of cytochrome c.

Step6: Answer 21b

Based on the above differences, humans are most distantly related to yeast as it has the highest number of differences in the amino - acid sequence of cytochrome c.

Answer:

19a. whale and tuna
19b. pig and chicken
19c. tuna and fly
20a. 21
20b. 10
20c. 1
20d. 13
20e. 10
20f. 44
20g. 29
21a. Rhesus monkey
21b. Yeast