Natural selection
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Natural Selection. Survival of the FITTEST. Charles Darwin. Charles Darwin: famous for the theory of natural selection. He is famous for studying finches and tortoises. He noticed that the animals on separate islands were similar in ways, but they were also different. . Darwin’s Finches.

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Natural Selection

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Natural selection

Natural Selection

Survival of the FITTEST


Charles darwin

Charles Darwin

  • Charles Darwin: famous for the theory of natural selection.

  • He is famous for studying finches and tortoises.

  • He noticed that the animals on separate islands were similar in ways, but they were also different.


Darwin s finches

Darwin’s Finches


Finches

Finches

  • These finches all had a common ancestor.

  • Due to natural selection, they all changed as they mated. Food sources changed, environments changed, predators changed, so the finches had to change with them to survive.


Who s gonna change

Who’s gonna change?

  • Let’s take humans for example. As the ozone layer depletes, the sun’s rays become brighter and more harmful. Obviously, bright sunlight is more harmful to a person with very light eyes. So, we’ll say that dark brown eyes are the MOST FIT for bright sunlight.

  • Ms. Britt cannot change her eye color to accommodate to the bright sunlight. So, the IMMEDIATE GENERATION does NOT CHANGE. It is their OFFSPRING THAT DOES THE CHANGING.


Natural selection

Sooo….

  • The sun becomes so bright that no person with blue eyes can withstand the LIGHT! (this is just hypothetically)

  • The blue-eyed people mate less and less. THIS MEANS THEIR GENES ARE NOT GETTING PASSED ON.

  • If the brown-eyed people are the only ones mating, then they will be the only ones passing on their genes. So the future generations will have BROWN EYES. The species has ADAPTED TO THE BRIGHT SUNLIGHT.


Now let s think of a real example

Now, let’s think of a real example

  • What are some things that animals/insects/plants/bacteria have to deal with in everyday life?

  • Predators

  • Finding food

  • Finding a mate

  • Are there any more you can think of?


Can you find the animal

Can you find the animal?

Is this animal fit for its environment? Why or why not? What genes will it pass to its offspring? What would happen to this species if the snow melted due to global warming?


Can you find the insect

Can you find the insect?

How does the traits of this insect allow it to adapt to its environment?


This is an albino skunk

This is an albino skunk.

Is this skunk fit for its environment? Why or why not? Would it survive to pass on its genes? Why do you think there aren’t many albino animals in the wild? Where could this skunk survive?


What are the conditions for natural selection

What are the conditions for natural selection?

  • The traits have to be hereditary (the organisms can pass them on to offspring).

  • More offspring are produced than needed. The population competes for food, water, shelter, etc.

  • Some of the characteristics of individual organisms allow them to be best suited for their environment.

  • The adaptations are inherited by future generations.


Adaptations

Adaptations

  • These are structures, behaviors, or functions that allows an organism to survive.

  • Camouflage would be an example.

  • How fast an animal runs.

  • Building nests on the edge of a cliff.

  • Having a beak that penetrates tree bark.

  • There are millions of examples of adaptations!


You see selection everyday especially artificial selection

You see selection everyday…especially artificial selection…

  • When people breed animals for certain traits, this is artificial selection.

  • Example: If you want a curly-haired retriever, one could breed a Labrador with a poodle.

  • We have chosen what traits we wanted.


Homework

Homework

  • Draw and explain an example of natural selection. It can be one that you have made up or a real example. Explain which trait is being chosen for and inherited and WHY THIS TRAIT IS THE “FITTEST.”


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