Communities & Biomes Chapter 03

Communities & Biomes Chapter 03

Abiotic Influences• Communities are groups of

populations of different species.• & the environment plays a big role

in how big a community will be.

Abiotic Influences• Food, water, temperature, and

others can all limit a community’s ability to survive.

• Therefore these are called Limiting Factors

• If there is a lot a food in an area, but no water what will happen to the community?

1. Limiting Factors

• Any biotic or abiotic factor that restricts the existence, numbers, reproduction, or distribution of organisms

Examples• Sunlight, Climate, Temperature,

Water, Nutrients/Food, Fire, Soil Chemistry, Space, Other organisms

2. Tolerance

• the lower and upper limits that an organism can survive in.

• (i.e. saltwater, temperature, oxygen levels, and any other limiting factors…)– A “range of tolerance”

3. Succession

• Overtime communities change.

•Natural changes and species replacements in a community are called SUCCESSION.

• Two Types

A. Primary Succession

• Colonization of new land by communities of pioneer species (first organisms in an area).

• Example: • After a volcanic lava flow.

http://www.countrysideinfo.co.uk/successn/primary.htm

B. Secondary Succession

• Colonization after a natural disaster.

• Example: • after a fire, flood, or mudslide

http://www.countrysideinfo.co.uk/successn/second.htm

Which type of success is which?

How do you know?

C. Climax Community

Mature, stable community; Equilibrium has been reached.

If a community is allowed to grow to the point where it is fairly stable, there is now, little or no change in species.Examples: sonoran desert, taiga, rainforest

II. Biomes

• Biomes are large groups ofecosystems that share

the same type of climax community.

• They are the Earth’s major life zones.

Earth’s Biomes

1. Aquatic Biomes

• freshwater biome

• marine/saltwater/ocean biome

a. Freshwater Biome

--- low salt concentration — usually less than 1%

Examples:Ponds and lakes Streams and rivers Wetlands

b. Marine Biome

o covers about ¾ of the Earth's surface o algae supply most of our oxygen and

absorb tons of carbon dioxide.

o Evaporation of the seawater provides rainwater for the land

Examples:Oceans ,Coral reefs Estuaries

2. Desert Biomeo covers about 1/3 of the Earth's surface o rainfall is less than 50 cm/yearo low and high altitudeso specialized plants and animals

ExamplesHot and dry Semiarid Coastal Cold

3. Forest Biomes

Tropical Temperate Taiga (Boreal)

a. Tropical forest

o greatest species diversityo only rainy and dry seasonso 12 hours daylighto always 20o-25oC

b. Temperate forest

oWell-defined seasons o with a distinct winter oModerate climate o loose leaves annually, oExamples: oak, elm, maple o -30° C to 30° C

c. Taiga forest (Boreal)

o largest terrestrial biomeo short, moist, warm summers & long, cold, and dry winters.o mostly conifers with needle-like

leaves; oExamples: fir, spruce, and pine

o precipitation is mostly snow

4. Grassland Biomeo Mostly grasses rather than large shrubs

or trees.o AKA – prairies or savannaso ideal for growing foodso rain in late spring and early summero large temperature range/variation o Most have been converted

into farms and grazing lands.

Examples:Arctic tundra - polar – high latitudeAlpine tundra –high altitude -Mtns.

5. Tundra Biomeo coldest of all the biomeso extremely low temperatureso little precipitationo very short growing seasonso Low biotic diversity (little variety in life)o Simple small plants/vegetation.