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.