4/14/14

Principals of Natural Selection: (Be able to explain)
1. All species have genetic variation
2. The environment presents many different challenges to an individuals ability to reproduce
3. Organisms tend to leave more offspring than they can support so individuals of a species often compete to survive.
4. Individuals within a population that are better able to cope with the changes of their environment tend to leave more offspring.
5. The traits of the individual best suited to a particular environment tend to increase in a population over time.


Endosymbiosis- The theory that proposes mitochondria and chloroplasts are the descendants of symbiotic aerobic eubacteria.

Four factors that support the theory:
1. Size and Structure- Mitochondria are about the same size as eubacteria and have two membranes.
2. Genetic Material- Mitochondria have circular DNA similar to DNA in bacteria.  Both mitochondria and chloroplasts have DNA different than the nucleus of the cell.
3. Ribosomes- Mitochondrial and bacterial ribosomes are similar in size and structure.
4. Reproduction- Like bacteria, mitochondria and chloroplasts reproduce by fission.