Transcript How do natural cycles affect ecosystems?

How do natural cycles affect
ecosystems?
Chapter 3 lesson 2
Earth’s Cycles
The Water Cycle:
The sun’s energy
1. Evaporation 2. Condensation 3. Precipitation causes water to
evaporate from
Earth’s surface and
form clouds. Then
gravity causes
precipitation to fall
to Earth and the
cycle begins again.
Succession- is the gradual long-term
change of species in an ecosystem.
• Ecosystems go through cycles called
succession.
• There are two major types of succession –
primary and secondary.
• Primary succession occurs when plants first take root in an
area that has no plants. This could happen after a volcanic
eruption covers an area with lava. The first plants that grow
would begin the process of primary succession.
Secondary succession takes place when most, but not all,
vegetation in an area has been removed.
• There are some plants and soil on which new plants can grow.
• For instance, a farmer could cut down trees to plant a cornfield.
There is a limited supply of Carbon on Earth. But it never runs
out because it is constantly recycled in the Carbon Cycle.
•
•
1.Plants use carbon dioxide during photosynthesis from the air,
water from the soil, and energy from the sun.
2. The
plant can usethrough
the food orEarth’s
store it asecosystems
starch. As a result
The carbon cycle is the
movement
of of
carbon
oxygen is released into the air. Humans breathe in
as solids, liquids, or photosynthesis,
gases.
the oxygen and exhale carbon dioxide.
3. When the plants die, they break down and decompose into the
soil. of cycling carbon from living things back into the
Respiration- the process
4. The carbon re-enters the soil, is compressed for thousands of
air and water.
years and can become fossil fuels.
5. When humans use (burn) these fuels, ie coal, carbon dioxide reenters the atmosphere.
The Nitrogen Cycle
The movement of nitrogen in different forms from living organisms to the
nonliving part of the environment and back
About 78% of the gas in Earth’s
atmosphere is nitrogen. However,
most organisms can’t use nitrogen
gas straight from the air. So an
important part of the nitrogen cycle
is the changing of nitrogen into a
form that plants can use. This is
called nitrogen fixation. Nitrogen
can be “fixed” by bacteria in plants
and soil or as the result of lightning
strikes.
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