Transcript Environment Chapter 2: Cycles in Nature

Environment
Chapter 2:
Cycles in Nature
Section 1: The Cycles of Matter
Section 1: The Cycles of Nature
• Matter-
anything that occupies space
and has mass
• The
cycles (water, nitrogen, carbon)
move matter among the environment
and living things
The Water Cycle
Water Cycle: the
movement of water
among oceans,
atmosphere, land,
and living things.
Brainpop!
Steps of the Water Cycle
•
Precipitation- water moves from the atmosphere to the land and oceans
•
•
Ex: rain, snow, sleet, hail
Evaporation- water moving from the land to the atmosphere
•
The sun’s heat causes water to change from liquid to vapor
•
Condensation- when water vapor cools forming a liquid that can fall as precipitation
•
Transpiration- water evaporates from living things back into the atmosphere
•
Ex: evaporation from leaves, perspiration from humans
•
Ground Water- precipitation seeps into the ground where it is stored in
underground caverns or in porous rock
•
Runoff- drainage of water from land after precipitation
The Water Cycle
The Carbon Cycle
• The
movement of
carbon from the
environment into
living things and
back again
• Carbon
is essential
to all living things
because it is part of
our molecules.
• Brainpop!
The Carbon Cycle
•
Photosynthesis- carbon moves from the environment into living things
•
Plants use carbon dioxide from the air to make sugar and animals get
carbon from eating plants
•
Respiration- carbon moves from living things back to the environment
when sugar molecules are broken down to release energy and carbon
dioxide is given off when animals exhale
•
Decomposition- carbon moving from dead organisms back to the
environment
•
•
Fungi and bacteria decompose dead organisms
Combustion- the process of burning fossil fuels releases carbon back
into the atmosphere
The Carbon Cycle
The Nitrogen Cycle
•
The movement of nitrogen from
the environment to living things
and back again.
•
•
Nitrogen fixation- the process of
bacteria in soil changing nitrogen
gas into usable nitrogen for plants
•
•
78% of our atmosphere is
nitrogen gas
Animals get nitrogen from eating
plants
Video Clips on Nitrogen Cycle
Environment
Chapter 2:
Cycles in Nature
Section 2: Ecological Succession
Section 2: Ecological Succession
•
Succession: a gradual development of a community over
time
•
Two types: Primary and Secondary
•
Primary Succession- development of a community where
nothing has existed before
•
Ex: New island, where a glacier melted revealing new
land
• Pioneer
species- fast-growing plants that help create soil
and create many seeds
•
Steps
Primary Succession
•
1. A retreating glacier exposes bare rock
•
2. Acids from lichens break down the rocks into
small pieces to form soil
•
3. When the soil is deep enough, mosses grow and
small insects begin to live in the community
•
4. Moss is replaced by ferns, then grasses and
wildflowers, then shrubs and small trees
•
5. After hundreds or thousands of years, a forest
develops
•
Video Clip about Primary Succession (4:24)
Secondary Succession
•
Secondary Succession- the redevelopment of a community after an
ecological disturbance (ex: forest fire, abandoned farmland)
•
Steps
•
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1. First year- weeds grow back (crabgrass)
•
2. Second year- weedy plants grow back (horseweed)
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3. 5-15 years- small pine trees grow back
•
4. 100 years- a forest forms
•
5. After pine trees die, hardwood trees (oaks, maples) grow back
Video Clip on Secondary Succession (1:15)