Explain, using examples, how Darwin and Wallace’s Theory of Evolution by Natural Selection accounts for:
– Convergent evolution
– Divergent evolution
- Compare convergent and divergent evolution, using two specific examples.
- Explain how the mechanism of natural selection accounts for convergent and divergent evolution.
Learn.
Convergent evolution is the development of similar features between species due to evolution despite the difference in location and/or different times. An example of this is commonly seen in the aerodynamic shape which can be seen in both birds and dolphins. Despite them evolving separately, they developed the same body shape which is extremely aerodynamic. Like wise, birds and bats underwent convergent evolution where they both developed wings for flight.
For the above two examples, the selective pressures where the same for the two different species resulting in the same adaptations for them. The bird and the dolphin both had to be aerodynamic so they could minimize energy and move quicker (or die if they didn’t) expenditure hence their shape. The bird and the bat had to fly to get flying insects (or die of starvation if they didn’t develop wings) hence the wings.
Divergent evolution is the development of differing features within a species due to changing selective pressures. This can be seen for example in the Galapagos island finches. When different populations of a species are separated as happened with the Galapagos finches on different islands unable to meet up with the finches on other Galapagos islands. Slowly the food sources changed in the islands hence the finches beak shapes evolved to make eating different food sources easier.
Memorise.
Convergent evolution: Different species develop same adaptations due to similar selective pressures. (Bird and dolphin aerodynamic)
Divergent evolution: Same species develop different adaptations due to different selective pressures. (Galapagos island finches)
Master.
Questions 1.
Compare and contrast convergent and divergent evolution using examples. [4 marks]
Question 2.
Explain how changes in environment can result in divergent evolution using an example. [3 marks]
Question 3.
Explain how changes in two different environments can result in convergent evolution using an example. [3 marks]
