1. What is a species? What makes two organisms different species?

2. What makes two organisms a different species
What makes two organisms a different species? Explain why using scientific vocab. Knowing this, what do you think a reproductive barrier is?

3. What are the 5 fingers of evolution
What are the 5 fingers of evolution? Which is the only one that leads to organisms becoming better adapted to their environment

4. Genetic Drift
change in allele frequency due to random chance.
Imagine a small group of twenty chickens consisting of 10 white and 10 brown individuals. If a fire kills off ten chickens and by sheer coincidence, all ten of them happen to be black, the frequency of the black trait in this population has gone from 50% to 0%. This can have large effects on small populations.

5. Non-random mating
If individuals choose mates that display certain characteristics over others, there will be a change in the ratio of traits. Again evolution has happened.

6. Mutations
Mutations are changes in genes that can create new traits. If a gene is mutated it can create an entirely new trait, which changes the ratio of traits in the population.

7. Gene flow is a fancy word for migration.
If individuals from a different population flood into an existing population, they can change the ratio of traits in the population.

8. Attention!!!
The first four causes of evolution do not necessarily cause an organism to be better adapted to its environment. Often times it is quite the opposite.
Natural selection is the only method by which a population of organisms can become better adapted to an environment over time.
It is also the main method by which one species splits into two different species.

9. Natural Selection
Natural selection is the only way populations of organisms can accrue adaptations to their environment or split in 2 species.
Natural selection is an unguided process by which traits that increase fitness become more abundant in a population over time.

10. Fitness
Fitness is how well an organism survives and reproduces. So, organisms in a population that have traits allowing them in some way to stay alive longer and reproduce more have a greater chance of passing these advantageous traits to their children.

11. In order for natural selection to occur, three things are necessary.
1. variation of traits within a population. Members of the population cannot be genetically identical.
2. difference in the survivability of individuals with different traits. Some organisms in the population will have traits that will help them survive and reproduce.
3. Genetic inheritance. The traits that cause this differential survival and reproduction must be heritable.
In order for natural selection to occur, three things are necessary.