Presentation

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I can explain how natural selection may lead to evolution.

Evolution

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Thinking Time

Can you remember what adaptation means from last lesson?

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Can you remember what adaptation means from the last lesson?

Adaptation is when a plant or animal has changed in some way, over a long period of time, to be better suited to the environment in which it lives.

Thinking Time

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The Peppered Moth

The Peppered Moth can be found all around Britain and Ireland. You may see them in your back gardens, but its amazing story has made it famous all over the world. An incredible scientist named Darwin discovered something amazing about this particular moth, and so

it is often referred to as 'Darwin's moth'.

Peppered Moths are normally white with black speckles across the wings, which is why they are called ‘peppered moths’. Their pat- tern means that they are well camouflaged when they rest on lichen-covered tree trunks during the day.

Question time!

Why do you think the moths wanted to camouflage themselves?

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The Dark Peppered Moth

However, in the 19th century, there were a lot of factories and coal fires which were causing the air to become ‘sooty’. This sooty air was being deposited onto the trees and covering them in a black layer. This meant the light coloured peppered moths were no longer camouflaged on the trees that they liked to sit on.

More and more light coloured moths were being eaten by predators such as birds because they were no longer camouflaged. Because of this, dark coloured moths became more common as they were the ones who could not be seen against the soot covered trees.

This is called natural selection.

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Natural Selection and Evolution

Evolution is a theory that states that all species that exist today developed from previous species. For example, some scientists believe that humans evolved from apes!

Natural selection is when organisms that are best suited to their environment survive and pass on their genetic traits. At the same time, organisms that are less likely to survive tend to be eliminated from the ecosystem.

The fittest, most adapted organisms survive and multiply whilst the least adapted die out.

This was shown with the moths. The light coloured moths were no longer adapted to their environment so started to die out. Whilst dark coloured moths were adapted to the environment so multiplied. Natural selection is key to explaining evolution.

genes - Information inside the cells of living things that is passed down from parents to their children. Eye colour and height are examples of traits controlled by our genes

New word alert!

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Watch this video from BBC bitesize for further explanation of evolution:

https://www.bbc.com/bitesize/articles/z9qs4qt

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Independent Task

You have pictures of different tree trunks on your sheet. Imagine

what the moths would have to look like to be best suited for that habitat.

Draw the pattern on the moths.

Activity

Imagine all the trees changed again.

Can you design a moth’s pattern which would camouflage it if all trees looked like the picture?

www.grammarsaurus.co.uk

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Recap

Can you remember what these words mean?

Explain what they mean to your partner.

adaptation natural selection evolution