Single answerDifficulty 3/5 · ChallengingOlympiadRepresenting dataArgumentation
Cytochrome c and the dolphin
Topic: Phylogeny & common ancestry
Cytochrome c is a small protein of the electron transport chain, about 104 amino acids long in vertebrates, and it is found in nearly all eukaryotes. A student compared its amino-acid sequence in six vertebrates and counted the positions at which each pair differs. The values are rounded and illustrative, in the range of published comparisons.
Data
| Species | Human | Chimpanzee | Horse | Dolphin | Chicken | Tuna |
|---|---|---|---|---|---|---|
| Human | — | 0 | 12 | 10 | 13 | 21 |
| Chimpanzee | 0 | — | 12 | 10 | 13 | 21 |
| Horse | 12 | 12 | — | 5 | 11 | 19 |
| Dolphin | 10 | 10 | 5 | — | 10 | 18 |
| Chicken | 13 | 13 | 11 | 10 | — | 17 |
| Tuna | 21 | 21 | 19 | 18 | 17 | — |
Which conclusion do these data best support?
Answer every part to submit.