Scenario: There are 3 types of polar bears: ones with thick coats, ones with thin coats, and ones with medium coats. It is fall, soon to be winter. The temperatures are dropping rapidly and the bears must be kept warm, otherwise they will freeze to death. Many of the bears have had 2 cubs each, but due to the extreme temperatures, many mothers only have one cub left.

Which bear did you think was most likely to survive?

Which bear did you think was most likely to survive?If the bears with

thick fur were the ones that survived – which bears are most likely to reproduce and pass on their genes to the next generation?

If the bears with thick fur were the ones that survived – which bears are most likely to reproduce and pass on their genes to the next generation?

What determines which species survive and which do not?

Evolution – The change in Evolution – The change in inherited inherited traits traits of a population over time, is of a population over time, is one one theory theory that explains how living that explains how living things that appear to be different are things that appear to be different are relatedrelated

First scientist to describe evolution

Believed that traits developed by a parent over time could be passed on to their offspring

Example: If a person was to practice running faster and faster, that person’s child would be born a fast runner

However, he was wrong!

- Charles Darwin-the father of evolutionary theory

- Sailed around the world studying finches (birds)

- Proposed that all organisms evolved from just one or two different organisms, millions of years ago!

- These older organisms spread out to different areas, and in their new areas, changed (evolved) to fit different ways of life.

Natural Selection: the process by which individuals that are better adapted to their environment are more likely to survive.

The species then reproduce and pass those successful variations (genes) to the next generation.

Adaptation: any trait that helps the chances of survival and reproduction

Structural Adaptations: - Some structural adaptations are

used for defense against predators

Examples:Thorns in plantsSpines in animals

Other forms of structural adaptations-- Mimicry – provides protection

by an organism copying the appearance of another species.

-- Camouflage – allows for organism to blend with its environment

If you were a bird….which of these moths would be easier for you to eat?

If you were a bird….which of these moths would be easier for you to eat?

D.N.A