1. Ecosystems: Components, Energy Flow, and Matter Cycling

2. Ecosystems: The Basics The grouping of plants, animals, and microbes we observe when we study a forest, grassland, a pond, a coral reef, or some other natural area is referred to as the area’s biota or biotic community. The grouping of plants, animals, and microbes we observe when we study a forest, grassland, a pond, a coral reef, or some other natural area is referred to as the area’s biota or biotic community.

4. Community: all the populations that live and interact in the same environment

5. Abiotic vs. Biotic Factors Abiotic factors: nonliving, physical and chemical factors Abiotic factors: nonliving, physical and chemical factors – Temperature, wind, pH, fire, etc Biotic factors: living, plants, animals, insects, etc Biotic factors: living, plants, animals, insects, etc

6. Biotic and Abiotic Factors in an Ecosystem

7. Ecosystems: The Basics Cont. The first step in a biotic community is the species present. The first step in a biotic community is the species present. Species include all those individuals that are like one another and that are distinct from another group (robins vs. redwing blackbirds) Species include all those individuals that are like one another and that are distinct from another group (robins vs. redwing blackbirds) – Can interbreed and produce fertile offspring

8. Ecosystems: The Basics cont. Each species is represented by a population Each species is represented by a population – Population- certain number of individuals that make up the interbreeding, reproducing group. Individuals within a given area Individuals within a given area – EX: all of the wolves in Yellowstone National Park

9. Examples of Species

10. Ecosystems: A Description Ecosystem: a community of different species interacting with one another and with their nonliving environment Ecosystem: a community of different species interacting with one another and with their nonliving environment – A stream, an entire forest, a desert

11. An ecosystem includes all the communities that live in an area, as well as, all the abiotic factors in the environment.

12. Ecosystems: A Description Boundaries very rarely occur between 2 different ecosystems. Boundaries very rarely occur between 2 different ecosystems. Many species will occupy and thus be a part of 2 or more ecosystems. Many species will occupy and thus be a part of 2 or more ecosystems. An ecotone is a transitional area between 2 ecosystems that shares many species and characteristics of both ecosystems An ecotone is a transitional area between 2 ecosystems that shares many species and characteristics of both ecosystems

15. The Biosphere The biosphere is the portion of the Earth in which biotic organisms (living) interact with one another and their abiotic environment. The biosphere is the portion of the Earth in which biotic organisms (living) interact with one another and their abiotic environment. The biosphere includes most of the hydrosphere and parts of the lower atmosphere and upper lithosphere. The biosphere includes most of the hydrosphere and parts of the lower atmosphere and upper lithosphere.

16. The Biosphere cont. So, the biosphere is all species and physical factors on Earth functioning as one unified ecosystem. So, the biosphere is all species and physical factors on Earth functioning as one unified ecosystem.

17. The Structure of an ecosystem Trophic Categories Trophic Categories – The major categories of organisms are Producers Producers Consumers Consumers Decomposers (detritus feeders) Decomposers (detritus feeders)

18. Producers (Autotrophs) Producers or autotrophs capture energy from the sun and convert carbon dioxide to organic matter (sugar) and oxygen. Producers or autotrophs capture energy from the sun and convert carbon dioxide to organic matter (sugar) and oxygen. Autotrophs make their own food Autotrophs make their own food This chemical conversion driven by light energy is called photosynthesis. This chemical conversion driven by light energy is called photosynthesis.

19. Photosynthesis

20. Consumers (Heterotrophs) Consumers or heterotrophs get their energy and nutrients by feeding on other organisms or their remains. Consumers or heterotrophs get their energy and nutrients by feeding on other organisms or their remains.

21. Consumers (Heterotrophs) cont. Depending on their source of food, consumers are classified as: Depending on their source of food, consumers are classified as: Herbivores (plant eaters) Herbivores (plant eaters) Carnivores(meat eaters) Carnivores(meat eaters) Omnivores (plant and meat eaters) Omnivores (plant and meat eaters) Scavengers (feed on dead organisms) Scavengers (feed on dead organisms) Decomposers (break down dead and decaying matter) Decomposers (break down dead and decaying matter)

22. Trophic Relationships: Food Chains A food chain is a sequence of organisms, each of which is a source of food for the next. A food chain is a sequence of organisms, each of which is a source of food for the next. A food chain determines how nutrients and energy move from one organisms to another through an ecosystem. A food chain determines how nutrients and energy move from one organisms to another through an ecosystem.

23. Trophic Relationships: Food Chains A food chain is a sequence of organisms, each of which is a source of food for the next. A food chain is a sequence of organisms, each of which is a source of food for the next. A food chain determines how nutrients and energy move from one organisms to another through an ecosystem. A food chain determines how nutrients and energy move from one organisms to another through an ecosystem.

25. Trophic Relationships: Trophic Levels Each organism in an ecosystem is assigned a feeding level or trophic level depending on whether it is a producer or consumer and on what it eats or decomposes. Each organism in an ecosystem is assigned a feeding level or trophic level depending on whether it is a producer or consumer and on what it eats or decomposes.

27. Trophic Relationships: Food Webs Because most species are a part of many food chains, the organisms on most ecosystems form a complex network of interconnected food chains called food webs. Because most species are a part of many food chains, the organisms on most ecosystems form a complex network of interconnected food chains called food webs.

28. Summary of Trophic Relationships Producer contain the most energy Producer contain the most energy As organisms eat other organisms, they expend energy to grow and reproduce. As organisms eat other organisms, they expend energy to grow and reproduce. This results in less energy being available for the next trophic level. This results in less energy being available for the next trophic level. Populations of heterotrophs, including humans, are limited by what plants produce. Populations of heterotrophs, including humans, are limited by what plants produce. If plants diminish, so do all other organisms at higher trophic levels. If plants diminish, so do all other organisms at higher trophic levels.