1. Topic 6 – The Best Selection

2. MEOOOOW! Woof! Domestic animals are house pets.
They have a long history of living with people
Before they were domesticated, they were wild animals! Humans have caught them and over time shaped the animals into the ones we know today.

3. We have seen how we can use biotechnology to create animals and plants with favorable traits.
People have used breeding (artificial selection) for thousands of years
Examples: Farmers breed cows to get the best milk

4. Artificial Selection
Artificial Selection is also called selective breeding.
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You select the best organisms for breeding so you get the best results.

5. Theory of Natural Selection
1. All organisms produce more offspring than can survive
2. There is incredible variation within each species
3. Some of these variations increase the chances of an organism surviving to reproduce
4. Over time, variations that are passed on lead to changes in the genetic characteristics of a species.

6. Artificial Selection vs. Natural Selection
DEFINITION: A person deliberately chooses a male and female with the desired traits and keep them for breeding purposes, while others are culled (got rid of). Over generations significant changes can occur in the species.
DEFINITON: The environment continually selects the individuals best suited to it, the individuals that survive get to reproduce, passing on their traits.

7. Pros and Cons of Artificial Selection
A gene shuffle to hopefully get the traits you want
better crops; animals for food
change can occur fast especially in plants (plants and animals are in captivity and are looked after)
Cons
HEALTH ISSUES
You may get unwanted traits (dogs with flattened faces have breathing problems, floppy ears-infections Dalmatians and Scottish terriers are 30% deaf), golden retrievers have hip problems, sharpies with wrinkled skin have rashes.
**LOSE VARIETY AND ABILITY TO RESIST DISEASE, ETC..

8. Pros and Cons of Natural Selection
allows for variation thus survival in
the ever changing environment.
less chance of being wiped out due
to a disease or virus.
Cons
takes a long time for change