1. Darwin &. Natural Selection http://www. youtube. com/watch

2. Charles Darwin (1809-1892) Darwin observed that:
1. The fossil record shows there is change over time in the plants and animals of the Earth
2. Organisms have different adaptations, for example, different kinds of teeth – carnivore teeth for ripping and herbivore teeth for grinding.
3. There is variation within a population of organisms – like the different types of coloration, size, etc.
He noticed these things over 100 years ago, and wrote Origin of Species!

3. HMS Beagle
Darwin went on a voyage collecting specimens and observing organisms.
In the Galapagos Islands, he observed finches.
He noticed something interesting about the finches…

4. Discuss with your neighbor!!!
Darwin’s Finches
What do you notice about the finches?
How are they similar/different?
How do you think the finches got this way?
Discuss with your neighbor!!!

5. All populations have variations.
Finches have variation within their populations!
Certain variations help or hurt the organisms.
In moths coloration and wing span can help the moth or hurt the moth.

6. SURVIVAL OF THE FITTEST
Fitness
The likelihood that an individual will reproduce and/or the number of offspring an individual produces over its lifetime.
Adaptive trait or adaptation
A trait that increases an individual’s fitness. `
Important things to note when discussion survival of the fittest:
Genotypes with high fitness become more common.
There are two ways to measure fitness: Absolute and Relative
Adaptations are the traits that allow organisms to survive the natural selection process which leads us into the next slide on Natural Selection
Have students think back to the albino rabbits and their M&M activity. Animals in polar regions over time become albino because those that had the albino mutation, which became an adaptation, had higher survival rates. 6

7. NATURAL SELECTION
Variation in traits is what drives survival of the fittest. Certain variations make the organism more fit, which allows the organism to survive and produce more offspring which will survive.
Evolution by natural selection is the key focus of this presentation.
IMPORTANT IDEA: Organisms produce more offspring than can survive!
Natural selection is possible because of a the variation in traits. You can provide to your class the example of beetles.
Some beetles are green and some are brown. Since the environment can’t support unlimited population growth, not all individuals get to reproduce to their full potential. In this example, green beetles tend to get eaten by birds and survive to reproduce less often than brown beetles do.
Heredity is another important focus of natural selection. The surviving brown beetles have brown baby beetles because this trait has a genetic basis.
And as natural selection occurs the end result is this: The more advantageous trait, brown coloration, which allows the beetle to have more offspring, becomes more common in the population. If this process continues, eventually, all individuals in the population will be brown.
Some individuals will be better suited to their environment - they will survive and reproduce more successfully than individuals without those characteristics. 7

8. Natural Selection requires four conditions:
1) There is variation in traits.
2) There is differential reproduction.
3) There is heredity.
4) The more advantageous individual survives and reproduces.
Natural selection work if all four conditions are true:
There is variation in traits. For example, some beetles are green and some are brown.
There is differential reproduction. Since the environment can't support unlimited population growth, not all individuals get to reproduce to their full potential. In this example, green beetles tend to get eaten by birds and survive to reproduce less often than brown beetles do.
There is heredity. The surviving brown beetles have brown baby beetles because this trait has a genetic basis.
End result: The more advantageous trait, brown coloration, which allows the beetle to have more offspring, becomes more common in the population. If this process continues, eventually all individuals in the population will be brown.
If you have variation, differential reproduction, and heredity, you will have evolution by natural selection as an outcome. It is as simple as that. 8

9. Facts about Natural Selection
Natural selection is not all-powerful. It does not produce perfection.
Natural selection is NOT random
Natural selection is a process
The population or individual does not “want” or “try” to evolve
Because natural selection can produce amazing adaptations, it's tempting to think of it as an all-powerful force, urging organisms on, constantly pushing them in the direction of progress — but this is not what natural selection is like at all.
First, natural selection is not all-powerful; it does not produce perfection. If your genes are "good enough," you'll get some offspring into the next generation — you don't have to be perfect. This should be pretty clear just by looking at the populations around us: people may have genes for genetic diseases, plants may not have the genes to survive a drought, a predator may not be quite fast enough to catch her prey every time she is hungry. No population or organism is perfectly adapted.
Second, it's more accurate to think of natural selection as a process rather than as a guiding hand. Natural selection is the simple result of variation, differential reproduction, and heredity — it is mindless and mechanistic. It has no goals; it's not striving to produce "progress" or a balanced ecosystem.
This is why "need," "try," and "want" are not very accurate words when it comes to explaining evolution. The population or individual does not "want" or "try" to evolve, and natural selection cannot try to supply what an organism "needs." Natural selection just selects among whatever variations exist in the population. The result is evolution.
At the opposite end scale, natural selection is sometimes interpreted as a random process. This is also a misconception. The genetic variation that occurs in a population because of mutation is random—but selection acts on that variation in a very non-random way: genetic variants that aid survival and reproduction are much more likely to become common than variants that don't. Natural selection is NOT random! 9

10. Variation
Major force behind evolution… where does variation come from?
Mutation- change in DNA
Gene flow (migration)- any movement of genes from one population to another
Gene Shuffling- crossing over in tetrad during meiosis

11. Gene Shuffling
Creation of new combinations of traits in sexual reproduction.
Some combinations can be good, some bad.

12. Major Points about Natural Selection
There is a struggle to survive.
More fit individuals are more likely to survive and produce offspring.
There is variation in populations; certain variations make organisms more or less fit.
The individuals that are more fit produce more offspring, which makes their adaptations more frequent over time.

13. Darwin’s Finches