What you will learn today . . .

• There are six recurrent themes that run throughout all aspects of biology: cell structure/function, stability and homeostasis, reproduction and inheritance, evolution, the interdependence of organisms, and hierarchy of organization

Themes of Biology

What are some highlights from Biology?

What are some highlights from Biology?

Recurrent themes in biology . . .

1. Cell Structure and Functiona. The cell is life’s basic unit of structure and

function

b. All organisms are composed of cells

c. The cell is the lowest organizational level that shows the characteristics of life

Recurrent themes in biology . . .

2. Stability and Homeostasisa. Even when organisms are faced with a

harsh environment, their internal conditions remain the same

b. Homeostasis: stable level of internal conditions

Recurrent themes in biology . . .

3. Reproduction and Inheritancea. DNA is passed through generations

b. DNA: biological instructions for an organism’s structure and function

c. This information is found on genes on chromosomes and is passed on through . . .*mitosis

*meiosis

Recurrent themes in biology . . .

d. Nucleotides (A, T, C, G): they are the same for all organisms but the order and amount is different

e. The way DNA is passed on differs as well

*Sexual reproduction

*Asexual reproduction

Recurrent themes in biology . . .

4. Evolutiona. Evolution is the changing of a population

over time, not necessarily the beginning of man. Why do populations evolve?

In response to the environment . . .

*to adapt

*to live

b. Single organisms do not evolve but groups of organisms do evolve.

Recurrent themes in biology . . .

5. Interdependence of organisms

a. Ecology: study of the interactions of organisms and their environments

b. Organisms depend on one another for food (food chains) and for energy (autotrophs versus heterotrophs)

Recurrent themes in biology . . .

6. Hierarchy of organizationatoms

molecules

macromolecules

organelles

cells

tissues

organs

organ systems

organism