Download File The Characteristic of Living Things1

The Characteristic of Living Things
7th grade science
All living things share important
characteristics
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Cellular organization
Contain similar chemicals
Use Energy
Respond to their surroundings
Grow and Develop
Reproduce
Cellular Organization
• all organisms are made up of small
building blocks called cells. Organisms
can be composed of only one cell or many
cells
Unicellular – single-celled organism
(Bacteria)
Multicellular - composed of many
cells that are specialized to do
certain tasks (Brain Cells)
You are made of trillions of cells. Specialized cells
in your body such as muscle and nerve cells, work
together to keep you alive.
The Chemicals of Life – the cells of all living
things are composed of chemicals
•The most abundant (common) chemical in cells is water
(H2O)
•Carbohydrates are a cell’s main source of energy
•Proteins and Lipids are the building materials of cells
•Nucleic Acids are the genetic material (chemical instructions)
Carbohydrate
Water
Lipid
Protein
Nucleic Acids are the genetic material
 See the “spiral” shape?
Energy Use – cells of an organisms use energy to
do what living things must do, such as repairing
injured parts – organism’s cells are always hard at
work!
Ex: as you read this sentence, your eye and brain
cells are at work! Your blood cells are busy moving
chemicals around your body.
Response to Surroundings – Have you ever noticed
that a plant stems bends toward the light? Plants and
other organisms react to changes in their environment.
A change in an organism’s environment is called a
stimulus. An organism reacts to a stimulus with a
response (which is an action or change in behavior).
Ex: Has the sound of a car horn ever startled you? The
sound was a stimulus that caused your response!
The Venus fly trap
responded to the stimulus
(the fly landing). The
response was that it
closed.
Example of Stimulus
a change in …
temperature
sound
light
amount of water
air quality
Example of Response
a change in …
Temperature (drops) Shiver
Sound (increases)
Dog runs away
Light
Pupils change size
water (decreases) Plant wilts
air quality (declines) people choke
Growth and Development – living things also grow and
develop. Growth is the process by becoming larger.
Development is the process of change that occurs during an
organism’s life to produce a more complex organism.
Growth
Development
Reproduction – another characteristic is an organism’s
ability to reproduce, or produce offspring that are similar to the
parents
Ex: robins lay eggs that develop into young robins that closely
resemble their parents.