Download Natural Selection Notes

Natural Selection Notes (Weds 2/22)
What is an Adaptation?
-Trait that helps an organism survive & reproduce
Examples: Beak shape of a bird, Poison in plant, Specialized
teeth of a shark
What is Natural Selection?
Process by which individuals better adapted to their
environment are more likely to survive and reproduce
First proposed by scientist Charles Darwin
What 4 Things affect
Natural Selection?
1. Genetic Variation- Animals are not all identical to each other
2. Overproduction-Animals produce more babies than can
survive
3. Competition- For food, space & mates.
Usually indirect, not actual physical fights
4. Selection- “Good traits” for environment are passed on
(Cannot develop adaptations in their lifetime)
Over long time, natural selection leads to changes in species
“Helpful traits” build up, “unfavorable” traits disappear
What is Evolution?
Gradual change in a species over time
The Theory of Evolution includes the ideas that all living things
are related & share a “common ancestor”