www.expertsmind.com/topic/biology/microbiology-92241.aspx

1. Biology Organisms

2. Populations

3. Ecosystems

4. The Biosphere

5. Life’s Levels of Organization
The world of life shows levels of organization, from the
simple to the complex, which extend through:
cells (made of?)
tissues & organs
organisms
populations
communities
ecosystems
the biosphere

6. Reductionist Principle
 The study of life is complex so • Chemicals
broken down into compartments
• Cells
 Within a cell
• Tissues
 Among cells in an organ • Organs
 Among the organ systems in an • Systems
organism • Organism
 Between organisms and the • Population
environment • Community
 Among individuals in a • Ecosystem
population
 Between species

7. The Cell, Structure & Function
What is a cell ?
(The cell is the Structural and functional unit of all living
organisms)
Two Types of cells:
1- Prokaryotic cells: cells without a nuclear membrane
The DNA is free in the cytoplasm: Bacteria and Cyanobacteria
2- Eukaryotic cells: has a proper nucleus with a nuclear
membrane: plants, animals ….

8. What does this figure describe? What else “flows” from producers to
consumers to decomposers?

9. I. Characteristics of Living Organisms
A. Living things share the following characteristics:
1. Living things are made up of units called cells.
a. Remember that cells are like little packages f
chemical reactions.
b. Life processes only occur as a result of chemical
reactions in cells (life is chemistry)
2. Living things reproduce.
3. Living things are based on a universal genetic code.
(Contain DNA)

10. 4. Living things grow and develop.
5. Living things obtain and use materials and energy. (Eat or
Photosynthesize)
6. Living things respond to their environment.
7. Living things maintain a stable internal environment.
(Maintain Homeostasis)
a. Homeo=Same Stasis= Status
8. Taken as a group, living things change over time. (Evolve)