EnvironmentChapter 2:

Cycles in NatureSection 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.

• 78% of our atmosphere is nitrogen gas

• Nitrogen fixation- the process of bacteria in soil changing nitrogen gas into usable nitrogen for plants

• Animals get nitrogen from eating plants

• Video Clips on Nitrogen Cycle

EnvironmentChapter 2:

Cycles in NatureSection 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

Primary Succession•Steps

•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

• 1. First year- weeds grow back (crabgrass)

• 2. Second year- weedy plants grow back (horseweed)

• 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)