Communities & Biomes A community is composed of interacting populations of different species. A biome is a large group of ecosystems that share the same climax community.

Limiting Factors A limiting factor is any biotic or abiotic factor that limits the existence, numbers, reproduction, or distribution of organisms. Examples: food, predators, water, habitat, temperature

Succession Ecologists refer to the orderly, natural changes and species replacements that take place in the communities of an ecosystem as succession.

Primary Succession The colonization of new sites by communities of organisms is called primary succession. New sites may be the result of lava flow, an avalanche, dune formation, or a receding glacier.

Pioneer Species The first species of plants to inhabit new land are called pioneer species. Mosses and lichens are the typical pioneer species. These plants are responsible for soil formation so other species of plants and animals can inhabit the area.

Secondary Succession Secondary succession refers to the sequence of community changes that occur after a community is disrupted by a natural disaster or human activity. Pioneer species are not necessary since bare soil covers the area.

Biomes Aquatic – located in oceans, rivers, lakes, streams, ponds, or other bodies of water Terrestrial – located on land

Marine Biomes Photic zone – portion of the biome shallow enough for light to penetrate Aphotic zone – never receives sunlight Intertidal zone – portion of the shoreline that lies between the high and low tide line Estuary – where saltwater and freshwater mix

Plankton Live in the photic zone Composed of mainly protists and marine larvae Phytoplankton – algae Zooplankton – animal-like plankton

A Review of the Terrestrial Biomes TUNDRA

Taiga or Coniferous Forest

Desert

Grasslands

Temperate Forest

Tropical Rainforest