Cycles in Nature
The Big Idea
Ecosystems change over time and depend on the cycling of matter.
Section 1
The Cycles of Matter
What You Need to Know
• / Diagram the water cycle, and explain its importance to living things.• / Diagram the carbon cycle, and explain its importance to living things.
• / Diagram the nitrogen cycle, and explain its importance to living things.
Vocabulary:
-Evaporation
-Condensation
-Decomposition
-Precipitation
-combustion
Section Summary
/ • / Precipitation, evaporation, transpiration, and condensation are parts of the water cycle./ • / Photosynthesis, respiration, decomposition, and combustion are parts of the carbon cycle.
/ • / In the nitrogen cycle, nitrogen gas is converted into other forms and back to gas again.
/ • / Many forms of matter on Earth pass through cycles. These cycles may be connected in many ways.
Section 2
Ecological Succession
What You Need to Know
• / Describe the process of succession.• / Contrast primary and secondary succession.
• / Explain how mature communities develop.
Vocabulary:
-succession
-pioneer species
Section Summary
/ • / Ecological succession is the gradual development of communities over time. Often a series of stages is observed during succession./ • / Primary succession occurs in an area that was not previously inhabited by living things; no soil is present.
/ • / Secondary succession takes place in an area where an earlier community was disturbed by fire, landslides, floods, or plowing for crops and where soil is present.
The Earth’s Ecosystems
The Big Idea
Earth’s ecosystems are characterized by their living and nonliving parts.
Section 1
Land Biomes
What You Need to Know
• / Distinguish between abiotic factors and biotic factors in biomes.• / Identify seven land biomes on Earth.
Vocabulary:
-Biome
-Desert
-Savanna
-tundra
Section Summary
/ • / A biome is characterized by abiotic factors, such as climate, and biotic factors, such as plant and animal communities.
/ • / Three forest biomes are temperate deciduous forests, coniferous forests, and tropical rain forests.
/ • / Grasslands are areas where grasses are the main plants. Temperate grasslands have hot summers and cold winters. Savannas have wet and dry seasons.
/ • / Deserts are very dry and often very hot. Desert plants and animals competing for the limited water supply have special adaptations for survival.
/ • / Tundras are cold areas that have very little rainfall. Permafrost, the layer of frozen soil below the surface of arctic tundra, determines the kinds of plants and animals that live on the tundra.
Section 2
Marine Ecosystems
What You Need to Know
• / List three abiotic factors that shape marine ecosystems.
• / Describe four major ocean zones.
• Describe 5 marine ecosystems
Vocabulary
-plankton
-estuary
Section Summary
/ • / Abiotic factors that affect marine ecosystems are water temperature, water depth, and the amount of light that passes into the water.
/ • / Plankton form the base of the ocean’s food chains.
/ • / Four ocean zones are the intertidal zone, the neritic zone, the oceanic zone, and the benthic zone.
/ • / The ocean contains unique ecosystems, including intertidal areas, coral reefs, estuaries, the Sargasso Sea, and polar ice.
Section 3
Freshwater Ecosystems
What You Need to Know
• / Describe one abiotic factor that affects freshwater ecosystems.
• / Describe the three zones of a lake.
• / Describe two wetland ecosystems.
• / Explain how a lake becomes a forest.
Vocabulary:
-littoral zone
-open-water zone
-deep-water zone
-wetland
-marsh
-swamp
Section Summary
/ • / An important abiotic factor in freshwater ecosystems is how quickly water moves.
/ • / The three zones of a pond or lake are the littoral zone, the open-water zone, and the deep-water zone.
/ • / Wetlands include marshes and swamps.
/ • / Sediments and decaying plant and animal matter build up in a pond. Over time, the pond may fill completely and become a forest.