1. Biology as a Science
Chapter 2

2. Characteristics of Living Things
Generally accepted characteristics of life – All living things:
Are made up of one or more cells
Reproduce
Grow and develop
Obtain and use energy
Respond to their environment

3. Characteristics: Cells
Unicellular – organisms consisting of only a single cell.
Multicellular – organisms which contain more than one cell (hundreds, millions, trillions, etc.)

4. Characteristics: Reproduction
Two basic kinds of reproduction:
Sexual – requires two cells from different individuals to unite to produce the first cell of a new organism.
Asexual – single organism is able to reproduce without the aid of another organism.

5. Characteristics: Growth and Development
Growth – to increase in size by natural means.
Development – cycle of changes that brings an organism into maturity.

6. Characteristics: Obtain and Use Energy
Anabolism – any process in a living thing that involves putting together (synthesizing) complex substances from simpler substances.
Catabolism – the final breakdown of a complex substance into a simpler substance.
Metabolism – total sum of all chem. Rxns in the body.

7. Characteristics: Respond to Their Environment
Homeostasis – the process by which an organism responds to stimuli in ways that keep conditions in their internal environment suitable for life.