Lesson 3: The
Needs of Living
Things
Grade 7 Science
Interactions in the
Environment
The Needs of Living Things
 Learning

Identify biotic and abiotic elements in an
ecosystem.
 Success


Goals:
Criteria:
I can name the basic needs of all living
things and why organisms need these
factors.
I can explain the importance of sunlight for
both plants and animals.
The Needs of Living Things
 The
physical space where an organism
lives is called its habitat. An organism can
only live in a habitat where its basic needs
are met.
 All living things need 5 basic needs for life:

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Sunlight
Air
Water
Food
Ideal temperature
5 Basic Needs for Life
 1.

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Sunlight:
Sun provides the energy that makes plants
and animals grow and reproduce.
Plants use sunlight to make their own food
(sugars). The amount of sunlight an area
receives determines what is able to live
there (e.g. dandelions like sun, while ferns
like shade).
Animals get their energy indirectly from the
sun when they consume plants.
Hours of sunlight varies with seasons
triggering flowering and migration.
5 Basic Needs for Life
 2.

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
Air
Air is made up of many gases, including
oxygen (O2), carbon dioxide (CO2) and
nitrogen.
Humans and many animals need oxygen to
live.
Plants absorb CO2 from the air to produce
sugars (food energy). They also release
oxygen during this process.
Without this process (photosynthesis) we
would not have enough oxygen!
5 Basic Needs for Life
 3.
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Water
ALL organisms need water.
Animals need water to digest food and
form body fluids, such as blood, that
distribute nutrients through the body.
Plants need water to grow and produce
their food.
Some plants and animals live in water.
Water also contains oxygen and CO2.
5 Basic Needs for Life
 4.

Food
Food provides organisms with nutrients.
 Nutrient:
o
o
o
a substance that an organisms
needs to grow and maintain its body.
Nutrients include sugars and starches, fats,
proteins, vitamins and minerals (such as
phosphates and nitrogen).
Plants that live on land absorb nutrients from
the soil and surrounding environment.
Animals obtain nutrients from the food they
eat as well as the environment.
5 Basic Needs for Life
 5.

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
Ideal Temperature Range
Temperature is affected by the interactions
of sunlight, soil, air and water
Temperatures on Earth can range from
-88 degrees Celsius to 50 degrees Celsius.
Most organisms have an ideal temperature
range in which they can live (think of
buying plants). For example, brook trout
prefer water temps between 4 and 20
degrees C and will only lay eggs when the
water temp is below 13 degrees.
Check your learning and your
notes…
 List
the 5 basic needs of all living things
and why organisms need each of these
factors to survive.
 Explain why sunlight is a basic need for
both plants and animals.
 Describe the different ways that different
organisms use water to survive.
 Name two ways plants affect human
survival.