Friday, November 5, 2010


Darwin’s theory of evolution is based on Natural Selection. Natural selection is based on the idea that the organisms gain mutations, or variations in their genes, and the ones who don’t gain variations are eliminated from the struggle for existence. 

These are the 5 requirements for Evolution:

1. There is variation in traits.
2. There is differential reproduction.
3. There is heredity.
4. The environment provides challenges.
5. There is a struggle for existence.

In the case of the seals, seals have evolved from freshwater animals to saltwater animals. Some little baby seal was mutated so that he could swim in saltwater as well as freshwater, and that skill came in useful when all of the freshwater fish started to die out. The other seals died, and the baby seal that could swim in saltwater as well as freshwater went into the salt water and found other seals that could swim in salt water as well. And that is how evolution works with seals.

In the case of penguins... There was a penguin who didn’t want to fly. He was born with flippery wings. There was no more food in the sky, so he went into the sea because he saw fish in the sea. He could eat fish, so that was good! And he swam in the sea one day, and caught a fish! So more fishy flippered penguins were born, and the penguins evolved into flightless birds so they could have more food.

A long long time ago, Antarctica was warm. As Antarctica moved north, the oceans around it grew colder. As it got colder, some fish died, and more and more fish died. But, inside the fishies, there were anti-freeze genes! A baby fish mutated so that he had anti-freeze protein, and he could survive in the cold! More and more fish gained this trait, and they could survive in the cold cold waters of the Antarctic.

See second post for pictures.

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