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Communities and Biomes

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Presentation on theme: "Communities and Biomes"— Presentation transcript:

1 Communities and Biomes
Chapter 3 Communities and Biomes

2 3.1: Communities Limiting factors- any biotic or abiotic factor that restricts the existence, numbers, reproduction, or distribution, of organisms Examples?

3 Sunlight Climate Atmospheric gases Temperature Water Nutrients or food Fire Soil chemistry Space Competition, predation, parasitism

4 Tolerance Ability of an organism to survive changes in biotic and abiotic factors

5 Section 3.1 Summary – pages 65-69
Ranges of tolerance Limits of Tolerance Organisms absent Organisms absent Organisms infrequent Organisms infrequent Greatest number of organisms Zone of Physiological stress Zone of Physiological stress Population Zone of intolerance Zone of intolerance Optimum range Range of tolerance Lower limit Upper limit Section 3.1 Summary – pages 65-69

6 Biological Succession
Succession- the process of change as it occurs to communities in an ecosystem Species that can be found in a particular ecosystem change over time

7 Primary Succession Colonization of barren land by organisms
Pioneer species-first species to inhabit an area Lichens, algae, bacteria, protists colonize bare rock, lava flows



10 Climax community A stable community that remains relatively unchanged for a period of time Represents by a variety of ecosystems- mature forest, grassland, coral reef, tundra, etc.

11 Secondary Succession A sequence of changes that takes place after an existing community is disrupted Disruption could be natural (fire, hurricane, flood) or human-influenced (farming, controlled burn, construction)


13 3.2: Aquatic & Terrestrial Biomes
Regional climate influences the distribution of biological communities Latitude and ocean currents influence the climate on different parts of the Earth

14 Section 3.2 Summary – pages 70-83
Latitude describes your position in degrees north and south of the equator. North pole Sun’s rays 66.5o 23.5o o Sun’s rays O Equator 23.5o Sun’s rays 66.5o South pole Section 3.2 Summary – pages 70-83

15 Saltwater Ecosystems Estuary- area where different types of water merge (temperatures, pH, salt/fresh) Intertidal zone- area where salt water and land meet, alternately submerged and exposed

16 Oceanic Zones The oceans can be separated into a variety of zones based on depth and proximity to the shoreline

17 Oceanic Zones

18 Intertidal zone- alternately submerged and exposed
Continental shelf- submerged edges of continents, relatively shallow water, high diversity Pelagic zone- open water, motile populations Benthic zone- sea floor of both continental shelf and pelagic zone

19 Light Availability Photic zone- portion of the water column which can be penetrated by light, from the surface to a couple of meters down Aphotic zone- portion of the water column beneath the photic zone where light cannot penetrate Phytoplankton- plant-like plankton, base of aquatic food chains, perform photosynthesis Zooplankton- animal-like plankton

20 Oceanic Zones

21 Section 3.2 Summary – pages 70-83
Freshwater biomes Greatest Greatest species diversity Warmer layer Oxygen and light penetration Colder layer Least Section 3.2 Summary – pages 70-83

22 Terrestrial Biomes Biome- major type of terrestrial ecosystem characterized by similar climate and resulting types of organisms

23 Tropical Forests Clustered near the equator
Can be tropical rain forests or tropical dry forests Relatively poor soil due to rapid decomposition and recycling of materials


25 Savannas & grasslands Biome dominated by grasses and small scattered trees Lack of water limits the size and number of trees


27 Deserts Desert biomes are defined by lack of water, not by temperature
Deserts can be both hot and cold Rain shadow- dry area on sides of mountains opposite prevailing winds


29 Desertification- conversion of other biomes into desert
Results from growing human populations, overgrazing, changing climate

30 Temperate Forests Dominated by hardwood trees which require sufficient moisture Deciduous trees- lose their leaves


32 Coniferous Forests Principal trees are coniferous
Needle-like leaves can remain all winter Many adaptations to periodic fire Taiga- northern boreal forest- fewer trees and harsher winters than coniferous forests, located just south of tundra


34 Tundra Arctic areas and tops of mountains
Permafrost- soil that is permanently frozen year round Plant life is very low-lying, no trees


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