18-3 Energy Transfer Producers and Consumers. Objectives Summarize the role of producers Identify...
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Transcript of 18-3 Energy Transfer Producers and Consumers. Objectives Summarize the role of producers Identify...
18-3 Energy TransferProducers and Consumers
Objectives
• Summarize the role of producers • Identify kinds of consumers • Explain the role of decomposers • Compare food chains and food
webs• Explain why there are only a few
trophic levels in an ecosystem
Producers
• Autotrophs: make their own energy/food
–As producers they make energy that other organisms can use
• Photosynthesis: Energy from light
• Chemosynthesis: Energy from chemicals
Deep sea ecosystems survive on chemosynthesis
Riftia tubeworms, mussels, and scavenging crabs found at the hydrothermal vent site
Measuring productivity• Gross primary productivity: Rate that
producers catch sun’s energy– Producers store energy in sugars
• Biomass: All the organic material• Net primary productivity: how much
biomass piles up– GPP minus rate of respiration– Kcal/m2/year– g/m2/year– Where do you think there is high Net PP– What about aquatic environments?
Only 5 % of the Earth’s surface is jungles that account for 30% of its NPPWeather accounts for a lot of NPP. Estuaries also have high levels of NPP because there is so much light and nutrients
Consumers
• Heterotrophs: get energy from outside of themselves– Eat or consume something else
Vore = Eat• Herbivore: eat producers (plants or herbs)• Carnivore: eat other consumers
– Carn = flesh
• Omnivore: eat everything– Omin = all– Most things are really at least a little bit of an
omnivore, even lions
• Detrivore: eat waste– Detri = garbage– Decomposers important
Others
• Insectivore• Bovivore• Planktavore• Cannibal: happens in nature
– Black widows, Mantis : eats the father– Mice will kill the babies if the nest is repeatedly
threatened– Many father’s kill the young– Why do this?
Energy flow
• When you eat something energy moves into you
• Trophic level: where do you fit in the food chain? Who eats you and who do you eat?
Food Webs
• There are many trophic relationships
• Food webs show the many connections between eater and eaten
Energy transfer
• How much does each trophic level store?– Only 10% of the energy makes it up to the
next level
• Why is so much energy lost?– Some prey escape– You can’t eat everything when you do catch
prey– Entropy: energy is always lost
• There are only a few trophic levels because energy runs out
Biological
magnification • toxins become
more concentrated with each link in a food chain.
• top-level carnivores are usually most severely affected by toxic compounds
How do producers and
consumers obtain energy?
• Producers: from light or chemicals
• Consumers: from eating something else
Name four types of consumers
• Herbivore• Carnivore• Detrivore• Insectivore
What important role do decomposers play in an ecosystem?
• Decomposers remove wastes preventing them from building up.
How does a food chain differ from a food web?
• Food chains are linear (straight)
• Food webs are spatial, and show more connections
Give two reasons for the low rate of energy transfer within ecosystems
• Some prey escape
• You can’t eat everything when you do catch prey
• Entropy: energy is always lost
Explain why food chains usually do not exceed three to four levels
• There is a low rate of energy transfer
• Very little energy gets transferred up
• Soon there isn’t enough energy to sustain life
pietà (pl. same; Italian for compassion) is an artwork depicting the Virgin Mary cradling the dead body of Christ. As such, it is a particular form of the devotional theme of Our Lady of Sorrows.
• American Pieta
What happens to an ecosystem if all the plants die? What happens if all the
decomposers die?
• If the plants die then the herbivores die, and then the carnivores die.
• If decomposers die then waste will pile up eventually poisoning the ecosystem
What is unreasonable about an ecosystem with 7 levels?
• There are to many levels because There is a low rate of energy transfer
• Very little energy gets transferred up
• Soon there isn’t enough energy to sustain life
Explain why there are more herbivores than carnivores
• Herbivores get energy from the largest source of biomass: plants
• Carnivores can’t get as much energy by eating other consumers
• This Biology Lecture brought to you by Muppet Star Wars