Ch.26 Ecosystems Ecology

Section 1: How Ecosystems Change Learning Objectives Explain how ecosystems change over time. Describe how new communities begin in areas without life. Compare pioneer species and climax communities

Section 1: How Ecosystems Change A. Ecological succession – normal, gradual changes that occur in the types of species that live in an area

1. Primary succession begins in a place without soil. a. Starts with pioneer species such as lichens, that can grow on rock.

b. New soil forms as weather and erosion break down rock. c. Decaying plants add organic material to new soil

2. Secondary succession begins in a place that has soil and once had living organisms a. Example: after a fire or removal of buildings b. Occurs faster and has different pioneer species than primary succession

B. Climax community – stable stage of ecological diversity and balance

Discussion Question Why does primary succession take longer than secondary succession?

Discussion Question Why does primary succession take longer than secondary succession?  New soil has to form from rock and organic material

Section 2: Biomes Learning Objectives Explain how climate influences land environments. Identify seven biomes of Earth Describe the adaptations of organisms found in each biome.

Section 2: Biomes A. Factors that affect biomes climate 1. Temperature 2. Precipitation

B. Major biomes – large areas with similar climates and ecosystems

Tundra

1. Tundra – cold, dry, treeless region a. Permanently frozen soil called permafrost b. Average winter temperature: -12 °C (10 °F) c. Average precipitation is less than 25 cm/year d. Plants: mosses, grasses, small shrubs, lichens e. Animals: insects, ducks, geese, other birds, mice, arctic hares, reindeer

Taiga

2. Taiga – cold forest of mostly evergreen trees a. Soil thaws in the short summer b. Precipitation: mostly snow, 35 – 100 cm/year

Temperate Deciduous Forest

3. Temperate deciduous forests – region with four seasons, mostly trees that lose their leaves in autumn a. Temperatures range from below freezing in winter to 30 °C (86 °F) or more in summer. b. Precipitation: throughout the year, 75 – 150 cm/year Temperate = temperature that is mild or in the medium; not too warm or too cold; not too wet or too dry.

Temperate Rain Forest

4. Temperate rain forest – tall trees with needlelike leaves a. Average temperature: ~10 °C (~50 °F) b. Precipitation: 200 – 400 cm/year

Tropical Rain Forest

5. Tropical rain forest – the most biologically diverse of all biomes a. Average temperature: 25 °C (77 °F) b. Precipitation: 200 – 600 cm/ year c. Four zones: forest floor, understory, canopy, emergents d. Human impact: Habitats being destroyed by farmers and loggers

Desert

6. Desert – driest biome, supports little plant life a. Temperatures: vary from hot to cold b. Precipitation: less than 25 cm/year c. Soil: thin, sandy, or gravelly d. Plant: cactus e. Animals: Kangaroo rat, scorpions

Grasslands

7. Grasslands – prairies or plains, dominated by grasses a. Temperatures: temperate or tropical b. Precipitation: 25 – 75 cm/year; dry season c. Animals: kangaroos, wildebeests; cattle

Section 3: Aquatic Ecosystems Learning Objectives Compare flowing freshwater and standing freshwater ecosystems Identify and describe important saltwater ecosystems Identify problems that affect aquatic ecosystems.

Section 3: Energy Flow A. Freshwater ecosystems – include flowing and standing water, low or no salt

1. Rivers and streams – flowing water a. Most nutrients washed into water from land b. The faster the flow, the greater the oxygen content.

2. Lakes and ponds – very little flow a. Sunlight warms and lights pond bottom, supporting plant and animal life. b. Deeper lakes support life along shallow shoreline or surface.

3. Water pollution – a problem caused by fertilizer-filled runoff and sewage

4. Wetlands – regions wet all or most of the year a. Lie between solid land and water b. Very fertile ecosystems

B. Salt water ecosystems – 95% of Earth’s water contains high concentration of salt, or high salinity.  Amount of salt = salinity

1. Open oceans – divided into lighted and dark life zones a. lighted zone – upper 200 m and home of plankton b. dark zone – below 200 m where animals feed on material that floats down or prey on each other  Lighted zone  Dark zone

2. Coral reefs – diverse and fragile ecosystems formed form coral shells of calcium carbonate

3. Seashores – along coastlines a. Intertidal zone – covered with water at high tide and exposed to air at low tide b. Drastic changes in temperature, moisture, salinity, and wave action

4. Estuaries – where a river meets an ocean; also called: bays, lagoons, harbors, inlets, sounds a. Rich in nutrients b. Changing mixture of salt water and freshwater

Discussion Question What is the general relationship between sunlight and aquatic life?

Discussion Question What is the general relationship between sunlight and aquatic life?  The more sunlight, the more abundant the plant life