CHAPTER 3Communities and Biomes

You will identify factors that limit the existence of species to

certain areas.You will describe how and why different communities form.

You will compare and contrast biomes of the planet earth

LIVING IN THE COMMUNITY

• Communities are interacting populations of different species.

• Abiotic and biotic factors interact and result in conditions that are suitable for life for some organisms and unsuitable for other organisms

• Biotic - living factors• Abiotic - nonliving factors

LIMITING FACTORS

• ---- FOOD• ---- PREDATORS• ---- TEMPERATURE• Any biotic or abiotic factor that restricts the

existence, numbers, reproduction, or distributions of organisms.

Environmental factors that affect an organism’s ability to survive its environment.

Range Of Tolerance

• The ability of an organism to withstand fluctuations in biotic an abiotic environmental factors.

• For example: • A range of temperatures• A difference of soil types• Amount of sunlight• Elevation

SUCCESSIONAs the land changes

• Changes over time• Orderly, natural changes• Species replacements that take place in the

communities of an ecosystem.

Stages of Succession

• Different species at different stages create conditions that are suitable for some organisms and not suitable for others.

• Two types of succession:• --------- Primary succession• --------- Secondary succession

Primary SuccessionColonization of new sites by communities of organisms.

• First species in an area are called pioneer plants• Example: Lichen• A stable mature community that undergoes little

or no change in species is a climax community

Secondary Succession

• Community changes that take place after a community is disrupted by natural disasters or human actions

• Lightning or flood• Farmer abandoning a field

• ECOSYSTEMS THAT HAVE SIMILIAR KINDS OF CLIMAX COMMUNITIES.

• LAND BIOMES: TERRESTRIAL BIOMES• LAKE, STREAMS, OCEANS: AQUATIC BIOMES

Aquatic BiomesLife in the Water

• Separate marine biomes into:• Shallow• Sunlit zones• Deeper• Unlighted zones• Estuary: coastal body of water, partially

surrounded by land, in which freshwater and saltwater mix.

Marine Biomes

Marine BiomeThe Effects of Tides Twice a day

• Intertidal zone: The portion of the shoreline that lies between the high and low tides.

• Tide pools: Pools of water left when the water recedes at low tide, vary greatly in nutrients and oxygen levels from the ocean.

• Much light but organisms have to contend with the crashing of waves.

Terrestrial Biomes

Key Terms

• Climax community Limiting factor• Primary succession Secondary

succession• Aphotic zone Biome Desert• Estuary Grassland Tundra• Permafrost Photic zone Plankton• Taiga Temperate forest• Tropical rain forest Intertidal zone