1. Natural Selection
SPI Analyze data on levels of variation within a population to make predictions about survival under particular environmental conditions.

2. Natural selection
Process by which individuals that are better adapted to their environment survive and reproduce more successfully than less well adapted individuals.
Survival of the fittest!!
Survival Means:
Living and passing on your traits to offspring (this ensures your species will survive)

3. Over time
Organisms inherit characteristics/ traits from their parents (inherited variation)
The characteristics of a population can change over time
The change of characteristics in a population is due to natural selection

4. Example Sea turtles lay multiple eggs at one time
Not all of the babies will make it to the ocean
Not all the babies will survive into adulthood
Not all the adults will reproduce
Only the offspring with the best traits will survive to pass on their traits to their offspring.

5. Four Parts Over production Genetic Variation Struggle to Survive
Successful Reproduction

6. 1. Overproduction
More offspring are born than will survive to become adults
Example:
Sea turtles
Salmon
Frogs
Dogs
Birds

7. 2. Genetic Variation w/in Population
Three Causes of variation:
1. Diversity of genetic traits from sexual reproduction
2. Diversity of genetic traits from mutations.
3. Changing environmental conditions.
Different characteristics improve chances of survival and reproduction
Example: albino alligators, rabbits with bigger ears, more aggressive lion, runt of the litter

8. 3. Struggle to Survive
Environments may not have enough food or water to support all born organisms
Some organisms may not be able to find food, or a mate.
Only the organisms with the best adaptations will survive
Example: zebra killed by lion, buck wins the fight for a mate vs. the losing buck

9. 4. Successful Reproduction
This is the key to natural selection.
Organism with the better adaptations to survive will more likely reproduce.
Less will adapted organisms will likely die early or produce few offspring
Example: bird that cannot build an adequate nest will raise fewer offspring