bio chap 10 ecology Flashcards
(13 cards)
what are producers
an organism that makes its own food
contains chlorophyll that absorbs light to convert co2 and water into glucose
- through photosynthesis
- glucose is a chemical store of energy
- oxygen is released in the process
what are consumers
organisms that are not able to make their own food
obtain energy and nutrients by feeding on other organisms
primary - feed on plants only
secondary - feed on primary
tertiary - feed on secondary
what are decomposers
eg bacteria fungi
organisms that get their energy and nutrients by breaking down dead organisms, faeces and excretory products
their activity return nutrients like mineral salts to the environment
what is a population
group of organisms of the same species that live tgt in a habitat
what is a community
made up of all populations of different species living and interacting with one another in a habitat
what is an ecosystem
community of organisms interacting wih one another and with its non living environment
what is a food chain
a series of organisms beginning with the producer through which energy and nutrients are transferred
each arrow represents a flow of energy
each stage of a food chain is known as a trophic level ( usually not >4)
what is a food web, predator & prey
consists of a network of interconnected food chains
predator: an animal that feeds on another animal
prey: an animal that is eaten by another animal
what are the first 3 steps of non-cyclic energy flow in an ecosystem - sun > photosynthesis > feeding
- in an ecosystem the principal source of energy is the sun
- during photosynthesis
- energy from the sun is absorbed by chlorophyll in producers and transferred to chemical stores of energy in glucose molecules - energy in the producers is passed from one trophic level to another by feeeing
- amt of energy from one trophic level decreases as it flows through the ecosystem
-> only some of the energy from one trophic level gets transferred to the next level
what is step 4 of the non-cyclic energy flow in an ecosystem: respiration
the rest of the energy is largely transferred to the env as heat through respiration
this energy does not return to the same system as the organisms that produced it
it cannot be recycled in the ecosystem -> flow of energy through ecosystem is non-cylical
what are step 5 and 6 of the non cyclic energy flow in an ecosystem: excretion & egestion > death
egested and secreted materials and dead organisms contain trapped chemical energy
this energy is released through the activity of decomposers
- decomposers use some of this trapped CE for their needs and the rest is transferred as heat to the env
why are short food chains more efficient in energy transfer
high amts of energy does not get passed from one trophic level to the next
it is lost to environment as heat/ uneaten body parts, faeces and excretory products
there will be less and less energy available for the organisms at the next trophic level as we move along the food chain
hence the food chains are generally short
the shorter the food chain, the higher amt of energy available for the final consumer -> less energy is transferred to the env
why do food chains have fewer than 5 trophic levels
energy transfer along the food chain would be inefficient
90% of energy lost as it is passed from one trophic level to the next
energy is transferred to the env as heat during respiration
energy transferred to uneaten body parts, faeces and excretory products
hence insufficient energy to support along food chain
