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.

B. Secondary Succession Colonization after a natural disaster. Example: after a fire, flood, or mudslide

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 of ecosystems 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 ococovers about ¾ of the Earth's surface oaoalgae 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 Biome ococovers about 1/3 of the Earth's surface ororainfall is less than 50 cm/year ololow and high altitudes osospecialized plants and animals Examples  Hot and dry  Semiarid  Coastal  Cold

3. Forest Biomes  Tropical  Temperate  Taiga (Boreal)

a. Tropical forest o greatest species diversity o nly rainy and dry seasons o 1o 12 hours daylight o always 20 o -25 o C

b. Temperate forest oWoWell-defined seasons o with a distinct winter oMoModerate climate o loose leaves annually, oEoExamples: oak, elm, maple o -30° C to 30° C

c. Taiga forest (Boreal) ololargest terrestrial biome o short, moist, warm summers & long, cold, and dry winters. o mostly conifers with needle-like leaves; oEoExamples: fir, spruce, and pine o precipitation is mostly snow

4. Grassland Biome oMoMostly grasses rather than large shrubs or trees. o AKA – prairies or savannas o ideal for growing foods o rain in late spring and early summer o large temperature range/variation o Most have been converted into farms and grazing lands.

Examples:  Arctic tundra - polar – high latitude  Alpine tundra –high altitude -Mtns. 5. Tundra Biome ococoldest of all the biomes oeoextremely low temperatures ololittle precipitation ovovery short growing seasons oLoLow biotic diversity (little variety in life) oSoSimple small plants/vegetation.