D 3 Types of Natural Selection 1 Directional

D. 3 Types of Natural Selection

1. Directional Selection a. Favors those w/extreme variations in traits w/in a population b. breeding of the greyhound dog -bred for speed - selected those who ran the fastest - Egypt 3 BC: used to hunt fastest game (fox, deer) http: //images. google. com/images? um=1&hl=en&q=greyhound

c. Wolves from Minn migrate to N. Canada for food -thicker coats are more fit -better chance of passing traits on http: //news. google. com/news? hl=en&q=wolves&um=1&ie=UTF-8&sa=X&oi=news_result&resnum=1&ct=title

2. Stabilizing Selection a. Favors the norm/average traits b. Siberian Husky bred for working in snow -medium dog w/ strong leg muscle -if heavier sink in snow -if lighter cannot pull sleds http: //images. google. com/images? um=1&hl=en&q=siberian+husky+pulling+sleds

c. Mice survival -small enough to hide from predators -large enough to fight rats for food -medium size best http: //www. wildaboutbritain. co. uk/files/mammals/Wood%20 Mouse%20 -%20 Apodemus%20 sylvaticus. jpg

3. Disruptive Selection a. Also favors the extreme traits b. Crabs live on shoreline -brown blend in better in water -lighter blend in better on land -medium more easily spotted & picked off in predation http: //www. the-islander. org. ac/oldsite/landcrabs. gif

• http: //upload. wikimedia. org/wikipedia/en/c/c 6/Selection_Chart. PNG