Characteristics of Life

Bio

Life

Biology

the study of life

Organism

a complete living being, meets all of the characteristics of life

8 characteristics of Life

1. Made of one or more cells

2. Hierarchical organization

3. Reproduces independently

4. Responds to stimuli

5. Maintains homeostasis

6. Grows and develops

7. Adaptations Evolve over time

8. requires energy

unicellular

made of one cell

multicellular

made of multiple cells

Prokaryotic cell

simple cells with no nucleus or membrane-bound organelles

Eukaryotic cell

complex cells with a nucleus and membrane-bound organelles

Hierarchical organization

1. Ecosystem (most inclusive)

2. Community

3. Population

4. Organism

5. Organ system

6. Organ

7. Tissue

8. Cell

9. Organelle

10. Molecule

11. Atom (least inclusive)

Sexual reproduction

2 parents involved- results in high genetic diversity

• Most animals and plants use sexual

Asexual reproduction

1 parent involved- offspring genetic clones of parent

• Mostly with bacteria, but some animals do it

Stimulus

anything in an organisms internal or external environment that causes a reaction

Response

the reaction to a stimulus

Homeostasis

the regulation of an organisms internal conditions to maintain life

Growth

increase in mass

Development

process of natural changes across a lifespan

Adaptation

any heritable trait that results in changes to the species over time

Photoautotroph

organisms that get energy from the sun, through photosynthesis

Chemoautotroph

organisms that get energy from chemical reactions through chemosynthesis

Heterotroph

organisms that get energy from eating or decomposing other organisms