The Characteristics of Life
Characteristics of Life

All living things:
Have cells
 Have Genetic Information
 Grow and develop
 Reproduce
 Respond to stimuli
 Maintain homeostasis
 Use Energy
 Evolve

1. Cells

A cell is the smallest unit of life.

Living things that are made of only one cell
are known as unicellular organisms.

Multicellular Organisms are made of many
cells that have specialized functions.
1I. Genetic Information

All living things have a genetic code.

Two types:
◦ DNA
◦ RNA
III. Growth and Development
•All
living things will grow and
develop from birth. Some go
through extreme physical
changes ( example a frog or
butterfly) This is known as
metamorphosis.
•Unicellular
organisms have
their one cell increase in size.
Multicellular organisms grow
in their total number of cells.
IV. Reproduction

All living things have the ability to reproduce
and create offspring.

Extinction often occurs when organism are
being killed off faster then they can reproduce.

Asexual reproduction produces offspring that is
genetically identical to its one parent.

Sexual reproduction produces offspring that
have 50% genetic information from each parent
V. Response to Stimuli
Internal Stimuli
An organisms reaction to changes
happening inside its body.
Example: hunger and thirst occur
internally.

External Stimuli
Changes in an organisms environment
that affect an organism.
Example: a reptiles response to
temperature change. The outside
temperature of the environment
cause the reptile to have more or less
blood flow to their skin

VI. Homeostasis

An organism's ability to maintain internal
conditions when outside conditions change
is called homeostasis.

Homeostasis is important because it ensures
cells continue to function. If cells do not
function properly an organism can become
ill or even die.
VII. Energy

The only living things that can produce their
own food are plants. All animals must
consume food in order to survive.

Almost all the energy provided to living
things begins with the sun.

The energy relationship between living
things is known as a food chain. Multiple
food chains make up an ecosystem’s food
web.
VIII. Evolve

All living things evolve, or change over time.

Three types:
◦ Microevolution – changes over a releatively
short period of time.
◦ Macroevolution – changes over a longer period
of time, enough that new species may separate
from established ones.
◦ Megaevolution – theory that all living things
arose from one common ancestor.