Aim: What are the characteristics of living things?

I. Organism – a whole living thing that carries out life functions.

A. All organisms carry out the following life functions:

1. Nutrition – the activities by which living things obtain food and process it for their use.

a. Autotrophic nutrition – organisms (green plants) make their own food (photosynthesis)

b. Heterotrophic nutrition – organisms must obtain their foods from outside sources (ingest food) of organic nutrients.

Heterotroph

Autotroph

2. Transport – the life function by which substances are absorbed, circulated, and released by living things.

3. Respiration – the life function by which living things convert the energy organic foods into a form more easily used by the cell.

4. Excretion - the life function by which living things eliminate metabolic wastes from their cells.

**Metabolism – the sum total of all the cell’s chemical activity.

5. Synthesis – involves the chemical processes of building large molecules from smaller molecules.

6. Regulation - the life function by which living things respond to changes within and around them, and by which all life processes are coordinated.

7. Growth – A process in which cells increase in number and size, resulting in an increase in size of the organism.

8. Reproduction – The life process by which new cells arise from preexisting cells by cell division.