13.3 Energy in Ecosystems

KEY CONCEPT Life in an ecosystem requires a source of energy.

13.3 Energy in Ecosystems

Prefixes

• Auto- ?• Hetero- ?• Homo- ?• Photo- ?• Chemo- ?• Herbi- ?• Carni- ?• Omni- ?• Hydro- ?

13.3 Energy in Ecosystems

Prefixes

• Auto- Self• Hetero- Different• Homo- Same• Photo- Light• Chemo- Chemical• Herbi- Plants• Carni- Meat• Omni- All• Hydro- Water

13.3 Energy in Ecosystems

Producers provide energy for other organisms in an ecosystem. Name three producers.

• Producers get their energy from non-living resources.• Producers are also called autotrophs because they make

their own food.

13.3 Energy in Ecosystems

Producers provide energy for other organisms in an ecosystem.

• Consumers are organisms that get their energy by eating other living or once-living resources. Name 3 consumers.

• Consumers are also called heterotrophs because they feed off of different things.

13.3 Energy in Ecosystems

Almost all producers obtain energy from sunlight. If the producer doesn’t use sunlight, what might they use? • Photosynthesis in most producers uses sunlight as an

energy source.• Chemosynthesis in prokaryote producers uses chemicals

as an energy source.

carbon dioxide + water +hydrogen sulfide + oxygen

sugar + sulfuric acid

13.4 Food Chains And Food Webs

KEY CONCEPT Food chains and food webs model the flow of energy in an ecosystem.

13.4 Food Chains And Food Webs

A food chain is a model that shows a sequence of feeding relationships. Why does “chain” fit this idea?

• A food chain links species by their feeding relationships. • A food chain follows the connection between one producer

and a single chain of consumers within an ecosystem.

DESERT COTTONTAILGRAMA GRASS HARRIS’S HAWK

13.4 Food Chains And Food Webs

Create your own food chain

• Beginning with a producer and including at least three organisms, give an example of a food chain.

13.4 Food Chains And Food Webs

• Consumers are not all alike.– Herbivores eat only plants.– Carnivores eat only animals.– Omnivores eat both plants and animals.– Detritivores eat dead organic matter.– Decomposers are detritivores that break down organic

matter into simpler compounds.

carnivore decomposer

13.4 Food Chains And Food Webs

• Specialists are consumers that primarily eat one specific organism or a very small number of organisms. What other kinds of “specialists” do you know?

• Generalists are consumers that have a varying diet.

13.4 Food Chains And Food Webs

• Trophic levels are the nourishment levels in a food chain.– Primary consumers are herbivores that eat producers. – Secondary consumers are carnivores that eat

herbivores. Name one example.– Tertiary consumers are carnivores that eat secondary

consumers. Name one example.– Omnivores, such as humans that eat both plants and

animals, may be listed at different trophic levels in different food chains.

13.4 Food Chains And Food Webs

A food web shows a complex network of feeding relationships. • An organism may have multiple feeding relationships in an

ecosystem. Give an example.• A food web emphasizes complicated feeding relationships

and energy flow in an ecosystem.

13.4 Food Chains And Food Webs

A food web shows a complex network of feeding relationships.

13.5 Cycling of Matter

KEY CONCEPT Matter cycles in and out of an ecosystem.

13.5 Cycling of Matter

Water cycles through the environment. Explain how.

• The hydrologic, or water, cycle is the circular pathway of water on Earth.

• Organisms all have bodies made mostly of water.

precipitation condensation

transpirationevaporation

water storagein ocean

surfacerunoff

lake

groundwater

seepage

13.5 Cycling of Matter

Elements essential for life also cycle through ecosystems. Name one.

• A biogeochemical cycle is the movement of a particular chemical through the biological and geological parts of an ecosystem.

13.5 Cycling of Matter

fossil fuels

photosynthesis

carbon dioxidedissolved in water

decompositionof organisms

respiration

carbondioxidein air

photosynthesis

combustionrespiration

• Carbon is the building block of life. Why do we call it that?– The carbon cycle moves carbon from the atmosphere,

through the food web, and returns to the atmosphere.– Carbon is emitted by the burning of fossil fuels.– Some carbon is stored for long periods of time in areas

called carbon sinks.

13.5 Cycling of Matter

• Oxygen cycles indirectly through an ecosystem by the cycling of other nutrients.

oxygen

respiration

carbondioxide

photosynthesis

13.5 Cycling of Matter

geologic upliftingrain

weathering ofphosphate from rocks

runoff

sedimentationforms new rocks

leaching

phosphate in solutionanimals

plants

decomposers

phosphatein soil

• The phosphorus cycle takes place at and below ground level.– Phosphate is released by the weathering of rocks. – Phosphorus moves through the food web and returns to

the soil duringdecomposition.

– Phosphorus leaches into groundwater from the soil and is locked in sediments.

– Both mining and agriculture add phosphorus into the environment.

13.5 Cycling of Matter

nitrogen inatmosphere

animals

denitrifyingbacteria

nitrifyingbacteria

nitrifyingbacteria

ammonium

ammonification

decomposers

plant

nitrogen-fixingbacteria in soil

nitrogen-fixingbacteria in

roots

nitrates

nitrites

• The nitrogen cycle mostly takes place underground.– Some bacteria convert gaseous nitrogen into ammonia

through a process called nitrogen fixation.– Some nitrogen-fixing bacteria live in

nodules on theroots of plants;others livefreely inthe soil.

13.5 Cycling of Matter

nitrogen inatmosphere

animals

denitrifyingbacteria

nitrifyingbacteria

nitrifyingbacteria

ammonium

ammonification

decomposers

plant

nitrogen-fixingbacteria in soil

nitrogen-fixingbacteria in

roots

nitrates

nitrites

– Nitrogen moves through the foodweb and returnsto the soil duringdecomposition.

13.5 Cycling of Matter

How do the activities of a keystone species affect the biodiversity of an ecosystem?

• A. They increase biodiversity. • B. They decrease biodiversity. • C. They have no effect on biodiversity. • D. Biodiversity remains the same but the species change.

13.5 Cycling of Matter

How do the activities of a keystone species affect the biodiversity of an ecosystem?

• A. They increase biodiversity. • B. They decrease biodiversity. • C. They have no effect on biodiversity. • D. Biodiversity remains the same but the species change. • Correct Answer = A

Which is a characteristic of an ecosystem in approximate equilibrium? • A. The kinds of organisms do not change. • B. Biotic factors do not change. • C. Abiotic factors do not change. • D. The total number of organisms do not change.

13.5 Cycling of Matter

How do the activities of a keystone species affect the biodiversity of an ecosystem?

• A. They increase biodiversity. • B. They decrease biodiversity. • C. They have no effect on biodiversity. • D. Biodiversity remains the same but the species change. • Correct Answer = A

Which is a characteristic of an ecosystem in approximate equilibrium? • A. The kinds of organisms do not change. • B. Biotic factors do not change. • C. Abiotic factors do not change. • D. The total number of organisms do not change.• Correct Answer = D

13.5 Cycling of Matter

Review

• Producers are organisms that can make their own energy from abiotic sources

• Consumers are organisms that must consume other organisms for energy.

• A food chain links organisms by their feeding relationships connecting a producer to a single line of consumers.

• A food web shows complicated feeding relationships • Water, nitrogen, oxygen, phosphorous, and carbon all cycle through

ecosystems.