Mechanisms of Evolution

Reindeer from a rancher in Alaska escape from their pen during an enormous snow storm. After their escape, they mate with wild caribou that are migrating across the land. The offspring of these have traits for short legs and have tame behavior.

• Gene Flow

• Genetic Drift

• Sexual Selection

• Natural Selection

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Males of the bighorn sheep species fight one another to show females who is the dominant male and are more likely to mate with females.

• Natural Selection

• Mutation

• Genetic Drift

• Sexual Selection

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During a hurricane, a population of beetles almost gets completely wiped out. The only beetles that survived were lucky that they were in their nest at the time of the hurricane and had enough food to survive.

• Natural selection

• Genetic Drift

• Gene Flow

• Non-Random Mating

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Insects become resistant to pesticides very quickly, sometime in one generation. If an insect is resistant to the chemical, most of the offspring will also be resistant. Considering that insect generations can be a matter of weeks, insects in an area can become immune to a chemical within months.

• Mutation

• Natural Selection

• Genetic Drift

• Gene Flow

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A chemical spill causes the offspring of ladybugs to have blue dots instead of black dots.

• Natural Selection

• Genetic Drift

• Mutation

• Gene Flow

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The country of Sweden is known for having people with blonde hair and blue eyes. One day a family moves from Sweden to India where dark hair and dark eyes are very common. A female from Sweden marries a male from India and their offspring now have blonde hair and blue eyed traits.

• Natural Selection

• Mutation

• Non-Random Mating

• Gene Flow

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A certain type of plant can produce blue or yellow flowers. During a fire, many yellow flowers are destroyed and now since blue is the dominant trait, the plant reproduces offspring that produce only blue flowers.

• Non-Random Mating

• Gene Flow

• Mutation

• Genetic Drift

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Some organisms of a population of birds are born with extra-long beaks instead of a normal sized beak.

• Gene Flow

• Natural Selection

• Genetic Drift

• Mutation

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In a habitat there are red bugs and green bugs. The birds prefer the taste of the red bugs, so soon there are many green bugs and few red bugs. The green bugs reproduce and make more green bugs and eventually there are no more red bugs

• Genetic Drift

• Natural Selection

• Gene Flow

• Mutation

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Females a certain bird species are attracted to the mating calls of male species more than others

• Genetic Drift

• Mutation

• Non-Random

• Natural Selection

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