121 NCEA Style Question: Patterns of Evolution

1. Large marine reptiles known as ichthyosaurs were common in ancient

New Zealand waters. Their outward appearance is similar to the dolphins that inhabit New Zealand waters today, and they probably behaved in very much the same way. Evidence suggests that at least some species of ichthyosaur gave birth to live young at sea, as dolphins do now.

Discuss the pattern of evolution illustrated by this example. In your answer you should consider the selection pressures acting on ichthyosaurs and dolphins during their evolution. You may use more paper if required.

3D

Ichthyosaur

Dolphin

2. New Zealand once had at least six species of wren, most of which evolved from a common ancestor between 22 and 18 million years ago. Only two species are living today. This large number of species is related to the break up of the New Zealand land mass during the Oligocene.

Describe the pattern of evolution shown in wrens. Explain how this pattern arises and discuss the factors that could have led to this pattern in New Zealand wrens. You may use more paper if required.

NZ rifleman