Chapter 3 Communities, Biomes, and Ecosystems Section 1: Community Ecology

Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology Communities A biological community is a group of interacting populations that occupy the same area at the same time. Oasis

Not every community includes the same variety of organisms. Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology Communities Therefore, your community also includes plants, other animals, bacteria, and fungi. Not every community includes the same variety of organisms. An urban community is different from a rural community and a desert community is different from an arctic community

Organisms adapt to the conditions in which they live. Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology Communities Organisms adapt to the conditions in which they live. Depending on which factors are present, and in what quantities, organisms can survive in some ecosystems but not in others.

Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology Limiting Factors Any abiotic factor or biotic factor that restricts the numbers, reproduction, or distribution of organisms is called a limiting factor. Aboitic factors includes sunlight, climate, temperature, water, nutrients, fire, soil chemistry, and space. Biotic limiting factors include living things, such as other plant and animal species.

Temperature also might be a limiting factor. Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology Limiting Factors Factors that restrict the growth of one population might enable another to thrive. For example, in the oasis, water is limiting factor for all of the organisms. Temperature also might be a limiting factor. Desert species must be able to withstand the heat of the Sun and the cold temperatures of desert nights.

Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology Range of Tolerance An upper limit and lower limit that define the conditions in which an organism can survive For example, steelhead trout live in cool, clear coastal rivers and streams from California to Alaska. The ideal range of water temperature for steelhead trout is between 13ºC and 21ºC.

Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology Range of Tolerance However, steelhead trout can survive water temperatures from 9ºC to 25ºC. At these temperatures, steelhead trout experience physiological stress, such as inability to grow or reproduce. They will die of the water temperature goes beyond the upper and lower limits.

3.1 Community Ecology Range of Tolerance Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology Range of Tolerance

Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology Range of Tolerance The ability of any organism to survive when subjected to abiotic factors or biotic factors is called tolerance. That is, the range of tolerance of water temperature for steelhead is 9ºC to 25ºC. Notice the greatest number of steelhead live in the optimum zone in which the temperature is best for survival.

At these temperatures, there are fewer fish. Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology Range of Tolerance Between the optimum zone and the tolerance limits lies the zone of physiological stress. At these temperatures, there are fewer fish. Beyond the upper tolerance limit of 25ºC and the lower tolerance limit of 9ºC, there are no steelhead trout. Therefore, water temperature is a limiting factor for steelhead when water temperature is outside the range of tolerance.

Ecological Succession Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology Ecological Succession Ecosystems are constantly changing. Forest fires can be good and even necessary for the forest community. Forest fires return nutrients to the soil. Some ecosystems depend on fires to get rid of debris. A forest fire might change the habitat so drastically that some species no longer can survive, but other species might thrive.

Ecological Succession Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology Ecological Succession The change in an ecosystem that happens when one community replaces another as a result of changing abiotic and biotic factors is ecological succession. There are two types of ecological succession—primary succession and secondary succession.

Primary succession usually occurs very slowly at first. Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology On a solidified lava flow or exposed rocks on a cliff, no soil is present. The establishment of a community in an area of exposed rock that does not have any topsoil is primary succession. Primary succession usually occurs very slowly at first.

Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology

As the organisms die, additional soil is created. Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology As pioneer organisms die, their decaying organic materials, along with bits of sediment from the rocks, make up the first stage of soil development. At this point, small weedy plants, including ferns and other organisms such as fungi and insects, become established. As the organisms die, additional soil is created.

Eventually enough soil is present so that shrubs and trees can grow. Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology Seeds, brought in by animals, water, or wind, begin to grow in the newly formed soil. Eventually enough soil is present so that shrubs and trees can grow. The stable, mature community that results when there is little change in the composition of species is a climax community. Scientists today realize that disturbances, such as climate change, are ongoing in communities, thus a true climax community is unlikely to occur.

Chapter 3 Communities, Biomes, and Ecosystems

Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology Disturbances such as fire, flood, or a windstorm can disrupt a community. After a disturbance, new species of plants and animals might occupy the habitat. Overtime, there is a natural tendency for the species belonging to the mature community to return

Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology The orderly and predictable change that takes place after a community of organisms has been removed but the soil has remained intact is secondary succession. Pioneer species – mainly plants that begin to grow in the disturbed area – are the first species to start secondary succession.

Chapter 3 Communities, Biomes, and Ecosystems 3.1 Community Ecology

Chapter Resource Menu Chapter Diagnostic Questions Communities, Biomes, and Ecosystems Chapter Resource Menu Chapter Diagnostic Questions Formative Test Questions Chapter Assessment Standardized Test Practice biologygmh.com Glencoe Biology Transparencies Image Bank Vocabulary Animation Click on a hyperlink to view the corresponding feature.

Chapter 3 Communities, Biomes, and Ecosystems Chapter Diagnostic Questions Mosses and lichens are the first organisms to appear during which ecological stage of an ecosystem? primary succession secondary succession climax community end succession D C B A CDQ 1

Chapter 3 Communities, Biomes, and Ecosystems 3.1 Formative Questions What is a group of interacting populations that occupy the same area at the same time? a biome a community an ecosystem an environment D C B A FQ 1

What occurs in the process of ecological succession? Chapter 3 Communities, Biomes, and Ecosystems 3.1 Formative Questions What occurs in the process of ecological succession? Environmental factors affect the survival of organisms. One biological community replaces another in the ecosystem. Organisms adapt to new biotic and abiotic factors. Pioneer species move in and replace existing species. D C B A FQ 3

Based on the information in the graph, what can be Chapter 3 Communities, Biomes, and Ecosystems Chapter Assessment Questions Based on the information in the graph, what can be inferred about carbon dioxide in the atmosphere? CAQ 2

Answer: The measured increase of carbon Chapter 3 Communities, Biomes, and Ecosystems Chapter Assessment Questions Answer: The measured increase of carbon dioxide (CO2) in the atmosphere is mainly due to the burning of fossil fuels. As carbon dioxide levels have increased, the average global temperature has increased. CAQ 3

Use the figure below to infer which abiotic factor Chapter 3 Communities, Biomes, and Ecosystems Chapter Assessment Questions Use the figure below to infer which abiotic factor might limit the survival of steelhead trout. Answer: Temperature CAQ 4

What is the most critical limiting factor for a polar bear? Chapter 3 Communities, Biomes, and Ecosystems Standardized Test Practice What is the most critical limiting factor for a polar bear? precipitation soil type sunlight temperature D C B A STP 1

The mature community in this diagram is a true climax community. Chapter 3 Communities, Biomes, and Ecosystems Standardized Test Practice The mature community in this diagram is a true climax community. true false B A STP 2

For which biome was this data collected? Chapter 3 Communities, Biomes, and Ecosystems Standardized Test Practice For which biome was this data collected? Average precipitation: 38–100 cm per year Temperature range: 10°C–40°C Abiotic factors: summers are very hot and dry; winters are cool and wet desert boreal forest temperate woodland tropical seasonal forest D C B A STP 3

What type of community is likely to exist near the top of a mountain? Chapter 3 Communities, Biomes, and Ecosystems Standardized Test Practice What type of community is likely to exist near the top of a mountain? tundra arctic desert coniferous forest temperate grassland D C B A STP 4

Section 1 Vocabulary community limiting factor tolerance Chapter 3 Communities, Biomes, and Ecosystems Vocabulary Section 1 community limiting factor tolerance ecological succession primary succession climax community secondary succession