1. Sources of Variation

2. Variation
Variation refers to differences among organisms of the same species or within the same population. There are three important processes that lead to variation within a population 1. Meiosis 2. Fertilization (sexual reproduction) 3. Mutations

3. Examples of Variation

4. Process 1: Meiosis Leads to Variation because of “cross over”

5. Meiosis
Meiosis is the process by which sex cells are created within the males and females of a species.
NO two egg cells carry the same set of DNA and similarly NO two sperm cells have the same DNA
This is all due to “cross over”

6. As you can see each of these egg cells has a different set of chromosomes with a different combination of genes

7. Process 2: Fertilization (Sexual Reproduction)
Now that there are a variety of sperm and egg cells, the combination of any sperm with an egg will create a different individual.
This is why, in most cases, you do not look exactly like your siblings or even your parents!

8. Process 3: Mutations in DNA

9. Mutations
Change the sequence of the base pairs that make up the DNA through
Deletions
Substitutions
Insertions
If the DNA sequence is changed too much then ultimately this affects the proteins that are synthesized.