Some Terms and Definitions

• 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.

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.

Ecotones on Land

• Shares many of the species and characteristics of both ecosystems

• May also include unique conditions that support distinctive plant and animal species

Terrestrial-to-Aquatic-System Ecotone

• Shares many of the species and characteristics of both ecosystems

• May also include unique conditions that support distinctive plant and animal species

Interrelationships Between Ecosystem Components“Everythingisconnectedtoeverythingelse”

Interrelationships Example

abiotic x abiotic temperature and rainfall = climate

abiotic x biotic water temperature predicts fish species

biotic x abiotic human pollution of the environment

biotic x biotic predator/prey relationships, life cycles, trophic levels

The Structure of Ecosystems

• 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

Consumers = Heterotrophs

• Primary consumers = herbivores = rabbit: eat plant material

• Secondary consumers = carnivores = predators = coyotes: prey are herbivores and other animals.

Consumers = Heterotrophs

• Parasites = predator = either plant or animal: prey are plants or animals.

Detritus Food Web

Trophic Categories

Trophic Relationships: Food ChainTrophic Relationships: 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 Trophic Categories with Trophic Level(s)

Trophic Levels

Category Producer Primary Consumer

Secondary Consumer

Third-Order Consumer

Autotrophs X

Herbivores X

Carnivores X X

Omnivores X X X

Parasites X X X X

Trophic Relationships Among Producers and Consumers

Food Webs = Food Chain Interrelationships

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

1Kcal

Biomass Pyramid

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?

Nutrient Cycles and Energy Flow

HW Questions(answer these 5 questions in a Word doc and bring the word doc to next class (do not submit or email it)!

HW questions (Contd)

• Q4. Define and compare the terms species, population, association, and ecosystem.

• Q6. Compared with an ecosystem, what are an ecotone, landscape, biome, and biosphere?

• Q7. Identify and describe the biotic and the abiotic components of the ecosystem such as the Gulshan Lake that is a part of your community.

• Q8. Name and describe the roles of the three main trophic categories that make up the biotic structure of every ecosystem. Give examples of organisms from each category.