Theory of Evolution and Mass Extinction

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Hi there- I'll go through each one.

Week 4 Quiz

1. Cite one piece of evidence supporting the theory of evolution. Why does it
support evolution?

This question can be answered in many different way- and I'm going to use a specific example to show change occurring and how it has occurred. It'll be quite detailed.

A simple answer (if you just want a quick one) is that the fossil record shows that animals change forms- ie they evolve. A particularly good example is seen in the fossil record of horses. Today rocks can be dated accurately and changes in form can be recorded.

An alternative - and more detailed way to answer this question would be to describe an example of natural selection in action. You may have studied the peppered moth in class. In the 1950's HBD Kettlewell; studied British population of the peppered moth Biston betularia This occurs in 2 distinct forms - the natural light peppered from which provides good camouflage when the moth is on lichen covered trees and a dark form.

Records from moth collectors showed that the first dark moth was found in Manchester in 1849, but a few decades later, by the end of the nineteenth century 98% were of the dark form. What had happened? It becomes easier to understand when you realize that the moths were eaten by birds. In pre-industrial Britain trees were covered in light colored lichens and any dark form moths that arose by mutation would have been eaten by birds. Pollution from the industrial revolution led to the death of the lichens on the trees. At this stage dark moths had a selective advantage as they were well camouflaged on the dark tree trunks and so were less likely to be eaten. And so the population of moths changed from the light form to the dark form. Today in Britain the dark from is found in polluted areas where the lichens have dies, and the light form is still found in rural unpolluted areas.

This provides a wonderful ...