If you were to take a large number of living things, you would notice that they all have something in common. However, you would also know that they are different as well.

All living things show UNITY (similarities) as well showing a great deal of DIVERSITY (differences).

Here is what all living things have in common...

1) All living things are highly organized and contain many complex chemical substances.

2) All living things contain one or more cells.

UNICELLULAR- contains just one cell
MULTICELLULAR- contains many cells

3) All living things use energy.

4) Living things have a definite form and have a limited size.

5) Living things grow.

6) Living things respond to changes in the environment.

7) Living things can reproduce.

8) Living things eventually die.

Nonliving objects may show one, or even a few of these characteristics but they never show all of them...

We can take these characteristics of life and simplify each...these will make up the 8 life functions.

Scientists classify things as alive if they can carry out these 8 LIFE FUNCTIONS.

R- Respiration
R- Regulation
R- Reproduction
E- Excretion
G- Growth
N- Nutrition
T- Transport
S- Synthesis

R R R E G N T S
=biology

Here is a look at the 8 life functions in a bit more detail...

RESPIRATION--
the breakdown of nutrients to yield (or give off) chemical energy
there are 2 types
1) aerobic respiration- uses oxygen
2) anaerobic respiration- doesn't use oxygen

REGULATION--
the process where a living thing controls and coordinates its various activities.
in animals--
1) nervous system uses nerve cells
2) endocrine system uses hormones
in plants--
some parts produce hormones

The 8 Life Functions