Environmental Science: Toward a Sustainable Future Richard T. Wright Chapter 2 Ecosystems: What They Are PPT by Clark E. Adams

The Organization of Ecosystems A description of ecosystems The structure of ecosystems The relationship between ecosystems and biomes Human impacts on ecosystem structure

Ecosystem Types in the United States Coasts and oceans Farmlands Forests Fresh waters Grasslands and shrub lands Urban and suburban areas

Ecosystems: A Description Biotic communities: grouping or assemblage of plants, animals, and microbes Species: different kinds of plants, animals, and microbes in the community Populations: number of individuals that make up the interbreeding, reproducing group Associations: how a biotic community fits into the landscape

How Ecosystems Are Formed Abiotics Plants Animals (moisture and temperature) (+ moisture = forest) (temperature = forest type) (lynx or bobcat) predict

Ecosystems A grouping of plants, animals, and microbes occupying an explicit unit of space and interacting with each other and their environment

Ecotone: transitional region between different ecosystems Shares many of the species and characteristics of both ecosystems May also include unique conditions that support distinctive plant and animal species

Ecotone: transitional region between different ecosystems Shares many of the species and characteristics of both ecosystems May also include unique conditions that support distinctive plant and animal species

Topics on Ecosystem Structure Trophic categories Trophic relationships: food chains, food webs, trophic levels Nonfeeding relationships: symbiosis Abiotic factors

Autotrophs = Producers = Self feeders

Inorganic and Organic Oxygen Carbon dioxide Nitrogen Water pH All living things Products of living things

Consumers = Heterotrophs Primary consumers = herbivores = rabbits: eat plant material Secondary consumers = carnivores = predators = coyotes: prey are herbivores and other animals Parasites = predator = either plant or animal: prey are plants or animals Detritus feeders and decomposers = bacteria and fungi: prey are plants or animals

Trophic Categories

Trophic Levels: Food Chain Third-order Consumer Secondary Consumer Primary Consumer Producer

Match Organisms with Trophic Level(s) Producer Primary Consumer Secondary Consumer Third-Order Consumer Plants X Rabbits Snakes Owls Bacteria

Match Organisms with Trophic Level(s) Producer Primary Consumer Secondary Consumer Third-Order Consumer Autotrophs X Herbivores Carnivores Omnivores Parasites

Trophic Relationships among Producers and Consumers

Food Webs

Trophic Level Energy Flow Third-order Consumer Secondary Consumer Primary Consumer - 100x - 10x 100 Kcal 10 Kcal 1 Kcal Producer 10,000 Kcal

Trophic Levels: Pyramid of Biomass 1 2 3 4 5 Which level is occupied by: producers? primary consumers? secondary consumers? third-order consumers?

Trophic Levels: Pyramid of Energy 1 2 3 4 5 Which level is occupied by: producers? primary consumers? secondary consumers? third-order consumers?

Symbiosis: Living Together + and + = Mutualism. Both species benefit by the interaction between the two species: yucca plant and Pronuba moth + and 0 = Commensalism. One species benefits from the interaction and the other is unaffected: remora fish and shark

Symbiosis: Living Together + and – = One species benefits from the interaction and the other is adversely affected. Examples are predation, parasitism, and disease. – and – = Competition. Both species are adversely affected by the interaction.

Resource Partitioning

Law of Limiting Factors

Application of the Law of Limiting Factors Compare the “tolerance” differences for a trout and a catfish using water: temperature (cold or warm). oxygen concentration (high or low). salinity (high or low).

From Ecosystems to Global Biomes The role of climate Microclimate and other abiotic factors Biotic factors Physical barriers

Climate and Major Biomes

Identify Biomes A to E Based on Temperature and Precipitation Levels: Answers on Next Slide Low High A B C D E Precipitation

Answers to Previous Slide A has high temperature and low moisture = hot desert B has low temperature and low moisture = cold desert (tundra with permafrost) C has medium temperatures and moisture = grassland D has high temperature and moisture = rain forest E has low temperature and high precipitation = arctic poles

Abiotic Effects of Latitude and Altitude

The Human Factor Three revolutions Neolithic Industrial Environmental

How Humans Modify Their Physical Environments to Meet Their Needs Produce abundant food Control water flow rate and direction Overcome predation and disease Construct our own ecosystems Overcome competition with other species

End of Chapter 2