1. Unit 3: Reproduction, Heredity and Evolution
How does life on Earth continue and adapt in response to environmental change?

2. All living things: Are composed of cell(s)
Have different levels of organization
Use energy
Respond to the environment
Grow
Reproduce
Adapt to the environment

3. Cells
Are the basic unit of structure and function of living things (all the “work” in an organism takes place in the cells).
Contain the genetic material (in the nucleus) that provides the instructions to direct all the activity (life functions) in an organism.

4. What is genetic material?
Chromosomes are the keepers of the genetic material in eukaryotic (with a nucleus) cells.
An organism has the same chromosomes for its entire life.
The chromosomes are located within each cell nucleus. Each somatic (body) cell in an organism has the same chromosomes.
Chromosomes provide the directions for how the cell is supposed to function and determine some characteristics about how the individual looks.
Each chromosome contains a very complex molecule called DNA.
The DNA molecule contains genes, which direct how an organism’s body is built and maintained.

5. Human Chromosomes

6. Drosophila (Fruit Fly) Chromosomes
Female Male

7. Summary
Different species have different numbers of chromosomes (humans have 46 while fruit flies have 8).
Chromosomes are homologous (They come in matched pairs of approximately the same size and shape, with each one containing slightly different information).