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Chapter 3. Communities and Biomes. 3.1 Communities. Community = conditions in one part of the world which are suitable for serving certain organisms Ex: your front lawn
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Chapter 3 Communities and Biomes
3.1 Communities • Community = conditions in one part of the world which are suitable for serving certain organisms • Ex: your front lawn • Limiting factors= any abiotic or biotic factor that restricts the existence, number, reproduction, or distribution of organisms • Ex: low temps, high elevation, strong winds, thing soil, sunlight, space • Sometimes factors that limit one population in a community may also have an indirect effect on another population • Ex: water drought = less plants produced = less food for cattle = less food for us
3.1 Communities • Tolerance = the ability of an organism to withstand fluctuations in biotic and abiotic environmental factors • Ex: corn in drought • Succession = change over time; orderly natural changes and species replacement that take place in the community • If grass was no longer cut on a lawn, what would it look like in one year? 5 years? 90 years?
3.1 Succession • The grass gets taller; weeds start to grow. The area resembles a meadow. • Later, bushes grow, trees appear and different animals enter the area to live. • The bushes and trees change the environment; less light reaches the ground. The grass slowly disappears. • Thirty years later, the area is a forest.
3.1 Succession • Primary succession = colonization of barren land by communities of organisms • Land were no living organism are • Ex: volcanoes • 1st species is pioneer species • Ex: Lichens • Eventually the pioneer species dies off soils slowly build up and it leads to a… • Climax community = stable, mature community that undergoes little or no change in species for 100’s of years. • *Doesn’t mean no change just a very little change so that it appears to be none over time
3.1 Succession • Secondary succession = sequence of changes that takes place after an existing community is severally disrupted. • Previously had life and still has soil; quicker bc different organisms are involved since soils are there • Ex: field that isn’t replanted, building destroyed
3.2 Biomes • Large group of ecosystem that share the same type of climax community • 2 Types: • Aquatic • Terrestrial
3.2 Aquatic Biomes • About 75% of earth is covered by water • Marine Biomes = • Photic zone = shallow waters that allow water to penetrate • Ex: bays, rocky shores, sandy beaches • Intertidal zone = between high and low tide where animals are specific to live in the conditions • Ex: star fish, barnacles • Plankton = small organisms that make up the bases of the aquatic food chain • Aphotic zone = deep water with no sunlight • Ex: deepest unexplored parts
3.2 Aquatic Biomes • Estuary Biomes = costal body of water partially surrounded by land in which fresh and salt water mix • Freshwater Biomes = • Different temperatures bring different organisms • Ex: lake- warm hot water brings cat tales yet when you reach the bottom where it is cold and little sunlight there is no plant life
3.2 Terrestrial Biomes • Tundra • Taiga • Desert • Grasslands • Temperate • Rainforest