Communities & Biomes

Communities & Biomes

Limiting Factor Any biotic or abiotic factor that

restricts the existence, numbers, reproduction, or distribution of organisms

Examples of limiting factors

• A.    Availability of food & water• B.     Predation• C.     Temperature – timberline• D.    Sunlight• E.     Climate• F.     Space

Cascade Mountain

Tolerance The ability of organisms to

withstand fluctuations in biotic and abiotic factors

Timberline on Mount Shasta

Succession• The orderly, natural changes and

species replacements that take place over time

• e.g. abandoned parking lot over 30 years

Types of Succession• Primary• Secondary

Primary Succession• The colonization of barren land (no living organisms exist there) by pioneer species

• Due to:• *Fire• *Flood• *Volcano

Primary Succession• Pioneer species (Lichens & mosses)

break up rock into soil

• Ferns & weeds further break up soil

• Seeds are carried by animals or blown by the wind

Secondary Succession• The sequence of changes that

takes place after an existing community is severely disrupted in some way (fire, flood, etc…)

• PREVIOUS LIVING ORGANISMS AND SOIL ARE PRESENT

Climax community• A stable, mature community that

undergoes little or no change in species

• a.      Can last hundreds of years• b.     Climax communities occur quicker

through secondary succession because soil is already formed (primary succession takes longer due to soil formation)

Biomes

TheTerrestrial Biomes• Tropical Rainforest• Tropical Dry Forest• Tropical Savanna• Temperate Grassland• Desert• Temperate Woodland & Shrubland• Temperate Deciduous Forest• Temperate Coniferous Forest• Temperate Rainforest• Taiga• Tundra

The Aquatic Biomes• Freshwater• Estuaries• Marine

• Aquatic Biomes are determined by depth, flow, temperature, & chemistry of the overlying water

Freshwater BiomesFlowing waterRivers & streams

Standing waterLakes & ponds

Wetlands*Bogs, marshes, swamps*Water covers the soil for part of the year

Estuaries• Salt-marshes & mangrove

swamps• Form where fresh & salt water mix• Called brackish water

MarineZonation of water by depth1. Photic zone – light can penetrate2. Aphotic zone – light DOES NOT reach3. Benthic zone – ocean floor

Zonation of water by distance from the shore1. Intertidal zone2. Coastal (Neritic) zone3. Open ocean