Environmental Science: Toward a Sustainable Future Richard T. Wright

Ecosystems: What They ArePPT by Clark E. Adams

Chapter 2

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

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 feedersAutotrophs = Producers = Self feedersAutotrophs = Producers = Self feedersAutotrophs = Producers = Self feeders

Inorganic and Organic

Inorganic Oxygen Carbon dioxide Nitrogen Water pH

Organic 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 ChainTrophic Levels: Food Chain

Third-order Consumer

Secondary Consumer

Primary Consumer

Producer

Match Organisms with Trophic Level(s)

Trophic LevelsOrganisms Producer Primary

ConsumerSecondary Consumer

Third-Order Consumer

Plants X

Rabbits X

Snakes X X

Owls X X

Bacteria X X X X

Match Organisms with Trophic Level(s)

Trophic Levels

Organisms Producer Primary Consumer

Secondary Consumer

Third-Order Consumer

Autotrophs X

Herbivores X

Carnivores X X

Omnivores X X X

Parasites X X X

Trophic Relationships among Producers and Consumers

Food Webs

Trophic Level Energy FlowTrophic Level Energy Flow

Producer 10,000 Kcal

Third-order Consumer

Secondary Consumer

Primary Consumer- 100x

- 10x

- 10x

100 Kcal

10 Kcal

1 Kcal

Trophic Levels: Pyramid of BiomassTrophic 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 EnergyTrophic Levels: Pyramid of Energy

1

2

3

4

5Which 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

Precipitation

Temperature

Low High

High

A

B

C

D

E

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 AltitudeAbiotic 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