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Flashcards in Ecology Deck (55)
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the environment in which a species normally lives



a group of organisms of the same species who live in the same area at the same time



a group of populations living and interacting with each other in the same area



- a community and its abiotic environment
- a stable and settled unit of nature consisting of a community of organisms interacting with each other and with their surrounding environment



the study of relationships between living organisms and their environment



organism that synthesises its organic molecules from simple inorganic substances



an organism that obtains organic molecules from other organisms



an organism that ingests organic matter



an organism that ingests non-living organic matter (decomposer)



an organism that lives in or on non-living organic matter, secreting digestive enzymes into it and absorbing products of digestion


food chain

a representation of relationships between organisms based on their diet (not including detritivores)


food web

diagram that shows how food chains are links together to form complex feeding relationships


advantages of food web

- shows complex interactions between species in a community/ecosystem
- shows more than one producer supporting the economy
- shows that a single consumer may have a number of different food sources (vice versa for producers)


trophic level

defines the feeding relationship of the organism to other organisms in a food chain (in a food web an organism can have multiple trophic levels)


most important energy source

the sun (light energy)


explain the energy flow in a food chain

- photosynthesis converts light into energy
- not all solar energy will be absorbed by chlorophyll so they won't all be trapped
- energy loss can occur due to respiration or in undigested food
- all energy will ultimately be lost as heat


problem with energy transfer from one trophic level to another

- inefficient transfer (only 10-20% of the energy on one trophic level is assimilated by the next level)
- in extreme environments, the initial trapping of energy by producers are low so the food chains are much shorter
- organisms on higher trophic levels are more prone to extinction due to reliance on organisms on lower levels
- any decrease in the population of an organism can cause a chain reaction


why are the shapes of pyramids of energy like they are?

- a pyramid of energy shows the flow of energy from one trophic level to another (unit: kJ/m2 yr)
- initial solar energy is not shown
- narrowing shape shows gradual loss of energy as you move up the food chain
- scale of diagram is written at the base of the pyramid (energy/area/time)


energy flow in ecosystem

- at every trophic level, energy is lost as heat
- narrowing of energy pyramid shows that all energy is eventually radiated as heat


matter cycles in ecosystems

- new matter is not created, nor is it lost the way energy is
- producers take organic molecules and convert them into organic compounds (helping them to be recycled and reused)
- consumers take the organic matter
- decompose recycle organic molecules found in dead organisms
- the process serves many functions including soul formation, reduction of high energy carbon compounds, and recycling nutrients stored in organic molecules
- mineral elements are absorbed by plants as ions
- the cycling process is called biogeochemical cycles



a group of organisms that can interbreed and produce fertile offspring


describe decomposition

- saprotrophic bacteria and fungi secrete extra-cellular digestive enzymes onto the dead organism
- the enzymes hydrolyse the biological molecules the dead organism is made up of
- the hydrolysed molecules are soluble and are absorbed by the fungi/bacteria
- organic molecules are oxidised, releasing CO2 back, and nitrogen in the form of nitrate/nitrite/ammonium


Carbon cycle processes

Carbon can be found in 4 pools (biosphere, oceans, atmosphere, and sediments) and it moves between these pools through a variety of biological, geochemical, or industrial processes
- photosynthesis
- respiration
- feeding
- fossilisation
- combustion


analyse changes in concentration of atmospheric CO2

- trends in atmospheric gases are studied as indicators of climate change
- CO2 is released unevenly around the world (partly due to vegetation distribution)
- base trend is increase in atmospheric CO2 levels
- bubbles of atmospheric gases trapped in ancient ice cores are analysed to determine CO2 levels
- temp can be determined from the ratio of O16 to O18
- concluded clear correlation between atmospheric CO2 and temp


relationship between rises in concentration of atmospheric CO2, methane, and nitrogen oxides with enhanced greenhouse effect

- gas molecules in atmosphere with 3+ atoms can capture outgoing infrared energy, scattering it and retaining it as heat
- average global temp will rise
- enhanced greenhouse effect is predicted to cause global climate changes


difference between greenhouse effect and enhanced GH effect

- GH effect is a natural phenomenon creating moderate temps on Earth to which life has adapted
- enhanced GH effect is the idea that human activity is increasing the levels of greenhouse gases, leading to increased global temps and climate change


precautionary principle

if the effect of a human-induced change would be very large/catastrophic, those responsible for the change must prove it won't be harmful before proceeding


burden of proof

those making claims must prove with evidence that their claim is true


general effects of climate change due to enhanced GH effect

- increased frequency and intensity of droughts
- flooding (due to higher temps causing expansion, increased rainfall, increased snow melts, rising sea level)
- permanent flooding of lands used for habitation/agriculture
- increased disease (warmer temps allow pathogens to flourish)
- more extreme weather
- more extreme temp variation all over the world
- loss of biodiversity as organisms cannot adapt


actions that may combat enhanced GH effects

- conservation of fossil fuels
- development of nuclear power/renewable power sources
- using biofuels to decay organic matter and photosynthesis products
- insulating homes better to reduce heating/cooling
- stop deforestation in tropical regions