More evidence for evolution

Question 1

What is comparative anatomy?

Answer 1

study of similarities and differences in the anatomy of different living species

Question 2

What is a homologous structure?

Answer 2

a structure that superficially appears different (and may perform different functions)

but it has the same underlying structure in different organisms

e.g. limbs of vertabrate

provides evidence for divergent evolution

Question 3

What is divergent evolution?

Answer 3

describes how form a common ancestor, different species have evolved with a different set of adaptive features

Question 4

What is comparative biochemistry?

Answer 4

study of similarities and differences in the proteins and other molecules that control life processes

Question 5

How can biochemical links show evolutionary relationships?

Answer 5

slight changes in molecules

e.g. cytochrome c, a protein involved in respiration and rRNA

Question 6

How are these molecules used to show links?

Answer 6

changes occur outside the molecule’s functional regions

these are called ‘neutral’ regions

the order of DNA bases and amino acids are compared

Question 7

How is the closeness of the links shown?

Answer 7

differences are plotted against the rate the molecule undergoes neutral base pair substitutions (which is predetermined by studies)

from this it can be estimated at which point two species shared a common ancestor