1. Mechanisms for Evolution

2. Natural Selection
Darwin found on his journey that certain animals were better suited for their environments than other animals
Darwin found that some of these animals were better suited to survival than others

3. Natural Selection
Darwin believed that certain animals were better suited to survival and that helped them live and have offspring
Those animals that lived and had offspring would be the ones that you see in the world
This idea was called natural selection

4. Natural Selection
Natural selection can only happen when one organism has an increased chance to spread its genes
The probability that an organism will pass on its genes to the next generation is referred to as fitness

5. Natural Selection
An organism that has an increase in fitness have a larger chance of passing on their genes
An organism that has a decrease in fitness has a smaller chance of passing on their genes

6. Overproduction
There are also several other things that Darwin noticed during his travels that helped form his opinion of natural selection
One of the things he noticed was the number of offspring that were produced

7. Overproduction
Most animals can produce more offspring than can survive to maturity
This means that some of the offspring will die when they are young
The offspring that will die are ones that will not be passing their genes on in the gene pool

8. Overproduction
The idea that some offspring do not survive to maturity and cannot contribute their combination of genes is called overproduction
Examples of this would be wild octopus
More octopus are produced each year than can survive

9. Genetic Variation
Darwin also noticed that within a population there are a difference in traits
The difference in traits creates a full range of traits within a species
This is easy to observe in any population

10. Genetic Variation
The range of traits within a population helps determine how natural selection proceeds
Natural selection tends to select for certain traits and have certain other traits die out
The range in traits is called genetic variation

11. Genetic Variation
The range in traits allows for a species to survive if some traits are not variable
If deer with large antlers are hunted and killed easier, there will be deer that have small antlers that would survive
If there were no variation among deer, none would survive

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13. Adaptation
Some of the variations help an organism survive in an environment
These variations tend to become more frequent in a population
The more frequent that trait is in a population, the better chance that population will survive

14. Adaptation
A trait that makes an individual more likely to survive in an environment is called an adaptation
Something like thick fur in a cold environment is a successful adaptation
Something like thick fur in a warm environment is not a successful adaptation

15. Adaptation
Remember an adaptation is a something that is passed down from the parents
Adaptations are not something that is spontaneous or planned by the organism

16. Artificial Selection
What is the process that Darwin proposed is the driving force behind evolution?
Natural selection is a process that occurs in the natural world
This means that no human can interfere

17. Artificial Selection Sometimes humans tamper with natural selection
This can be seen most often in dogs
Humans tend to want dogs with certain desirable traits
They breed dogs together that have these traits

18. Artificial Selection
Artificial selection is the process of humans selecting individual traits to give to the next generation
It is the only way that we could have gotten one of these from one of these

19. Video Watch First! http://www.youtube.com/watch?v=nVSJNhUhV-4
Watch Second!