Concepts of convergence and divergence in evolution (3)

Question 1

Groups of species undergo various kinds of natural selection and, over time, may engage in several patterns of evolution: (4)

Answer 1

• convergent evolution
• divergent evolution
• parallel evolution
• co-evolution

Question 2

What is convergent evolution?

Answer 2

Convergent evolution is the process during which species that are not closely related to each other independently evolve similar kinds of traits to adapt to similar environments or ecological niches.

Question 3

What are examples of convergent evolution? (2)

Answer 3

• Bees, hawks, and bats all have wings. None of these organisms owes its wings to genes inherited from any of the others, i.e. they were not present in the last common ancestor of each. Each kind of wing evolved independently, suggesting that the trait of flight is a useful one for the purpose of survival and reproduction. These independently evolved wings are called analogous structures. These animals ‘converged’ on this useful trait.
• Flightlessness has evolved in many different birds independently. For example the ostrich (South Africa), emu (Australia), cassowary (Australia), rhea (South America) and kiwi (New Zealand) are all not related.

Question 4

How does divergent evolution?

Answer 4

Divergent evolution is the process in which a trait held by a common ancestor evolves into different variations over time.

Question 5

What is a common example of divergent evolution?

Answer 5

A common example of divergent evolution is the vertebrate limb trait. The human, horse, bat and bird fore-legs and the whale flipper most likely evolved from the front flippers of an ancient jawless fish. Because they share a common evolutionary origin, these are examples of homologous structures.