biology and evolution!!! help me=]?

Question

okay these questions have to do with evolution!

1. There is a difference of only one amino acid in one chain of the hemoglobin of humans and gorillas. What might have caused this difference???!!!

2. If the amino acid sequences in the proteins of two organisms are similar, why willl their DNA also be similar?

3. Many biologists believe that the number of differences between the proteins of different species indicates how long ago the species diverged from common ancestors. Why do these biologists believe that humans, chimpanzees, and gorillas diverged from a common ancestor only a few million years ago?


the last ones long.s orry.

if you happen to know the answers to all or any of these please respond!!!!!!

Answer 1

1. Many things could have caused the difference initially. There could have been a random mutuation in the DNA of the ancestors of either gorillas or humans. If that mutation gave much greater evolutionary fitness, (possibly by ability to carry more oxygen molecules?) then the changed amino acid would have been passed down to more offspring.

2. Amino acid sequence is translated from the mRNA sequence, which is transcribed directly from the DNA sequence. If the amino acid sequences are similar, the DNA sequences must also be similar.

3. Because those species have similar DNA sequences and proteins.

Answer 2

1) The difference was probably caused by a genetic mutation in the DNA responsible for creating the proteins.

2) As I mentioned in the first answer, DNA tells the amino acids how to get together to form proteins. If the proteins are similar, the instructions for making them must have been similar too.

3) They have an estimate of about how often mutations arise in a species and stay there (i.e, they provide an evolutionary advantage and are passed along, rather than providing a disadvantage and being eliminated). Assuming that since we diverged from our common ancestor, we've been mutating at about the same rate, then we've each experienced a number of beneficial mutations equal to about half of the difference between us. Figure about how long it would have taken to get that many mutations and you have a rough estimate of how long it's been since we diverged.