D.N.A: SWBAT determine how structural differences/variations may affect the survival rate of members within a species. 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 is 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?

Natural Selection and Adaptation What determines which species survive and which do not? Natural Selection and Adaptation

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

Why are giraffes necks so long Why are giraffes necks so long? Over time, how did giraffes necks develop to be so long?

Jean Baptiste de Lamarck 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 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.

Darwin’s Theory of Natural Selection! 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 Adaptation: any trait that helps the chances of survival and reproduction

3 Types of Adaptation Structural Adaptations: - Some structural adaptations are used for defense against predators Examples: Thorns in plants Spines in animals

Structural Adaptations

More Structural Adaptation 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

Mimicry

Mimicry

Camouflage

Camouflage

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

D.N.A D.N.A