5.4 - Cladistics

Question 1

Define clade

Answer 1

A group of organisms that evolved from a common ancestor

Question 2

Outline the use of a ‘molecular clock’ to determine time since divergence between two species

Answer 2

Evidence that mutations occur at a roughly constant rate so they can be used as a moecular clock -> the number of differences in sequence can be used to deduce how long ago dfferent groups split from a common ancestor.

Question 3

Contrast why homologous and analogous structures are simlilar to themselves.

Answer 3

H - due to similar ancestry

A - due to convergent evolution

Question 4

State an example of analogous and homologous traits

Answer 4

H - chicken wing and human arm (other pentadactly forelimbs)

A - human eye and octupus eye