Natural Selection

Natural selection was a creation of the all mighty Charles Darwin and Alfred Russel Wallace!! In 1859 they came up with this nifty idea by studying Finches in the Galapagos Islands.Darwin and Wallace found that the Finches on one of the islands had different sized beaks then others on the different islands. Now as you can probably imagine they wondered why that was, because they were the same bird right? Well after studying the birds and their habitats they came to the conclusion that there beaks were different sizes because of their food! The birds on one island had different conditions when getting food so their beaks adapted so they could reach their food. Finally Darwin and Wallace cracked the code to there new theory of Natural Selection!

Well Natural Selection is a mechanism of evolution due to a change in an environment. It occurs when something happen to an environment, for example lets say that a species of Giraffe eats shrubs close to the ground, but all of a sudden a disease wipes out the low shrubs from there habitat. What will happen next? Well Next the Giraffe would have to adapt to the change and grow longer necks to reach the shrubs that are higher up ,and so they adapt to survive in their habitat! And that is a perfect example of Natural Selection in its glory! There was a change in a environment and there was evolution.

When learning about Natural Selection you have to keep in mind that there is more than one selection! You are probably thinking "Oh no! Not more!" Yep theres more but they are pretty simple!

1. Directional Selection- only one extreme trait is favored (physical appearance like the Moth and Mouse example above!)
2. Stabilizing Selection-the middle or average trait is being favored (Birth weight)
3. Disruptive Selection-both extreme traits are being favored but not middle color.(light and dark colored organisms are bing favored but not middle color)

Now you probably are wondering how your supposed to remember them well its simple! When you think of Directional Selection think of the pop band One Direction because only one trait is being favored!

For stabilizing Selection think of siting in the middle of a teeter toter , in order to stay there you have to stabilize your weight.

And for Disruptive Selection think about a disruptive class when a teacher is teaching , you can hear both the teacher and the students talking and its disruptive.

Biology notes collected from Mrs.Larrabee,and Mrs.Garber fourth hour class.

Email: ella.norman@eskymos.com