Natural selection

Learning objectives:-Level 3- Recall that some organisms compete with each other for resources.Level 4- Describe the theory of natural selection.Level 5- Explain how competition between organisms can lead to evolution.Level 6- Explain why Darwin did not publish his ideas straight away.Level 7- Speculate why some people may have been against Darwin’s ideas when it was first suggested

Key words: Survival of the fittest, selective advantage, variation

What are the differences between these two moths? Why might one be

better adapted than the other?

Extra challenge: How does the environment affect the number of moths of each colour?

Survival of the fittest

Use the information from the video to draw a picture explaining “survival of the fittest.” You may only use 2 sentences to explain your picture!

http://www.bbc.co.uk/learningzone/clips/natural-selection-and-survival-of-the-fittest/5516.html.

Adaptations

• We know that species are adapted to suit their environment (think of the camel and polar bear).

• What happens to those which are not well adapted?

• This is survival of the fittest.

Darwin’s finches• On his voyage on the Beagle Darwin

stopped at the Galapagos islands.• Here he discovered some unique

species including and observed a variety of finches.

Darwin’s Finches

From one species of finch, several others have evolved over time. Depending on the environment they inhabit, they have evolved adaptations that make them better suited for their niche.

Darwin’s finchesDifferent islands in the Galapagos have different habitats and food types.

Discuss: Why might different species of finch exist on different islands?

Extra challenge: How did Darwin use natural selection to explain what he saw on the Galapagos?

Be ready to share your ideas with the class.