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7 Cards in this Set

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What is meant by classification?


What is meant by species?


What is meant by adaptation? Give examples


Why are new species moving in another species' habitat a threat?


What do food webs show?



Classification: Groups of species with similarities. We are homo sapiens


Species: Group of organisms so similar that they can breed together to produce fertile offspring.


Adaptation: Features that help organisms survive in environment.


New species: Threat because they could compete for same food/shelter. They could be predator. They could harbour disease that wipes out other species population


Food web shows interdependence of species.



What happens during photosynthesis?


What status are plants given in food web?


What status are animals given in food web and why?


Of the energy that gets passed on at each stage of web, some gets used for other means. What are they?


How is energy released to decomposers and detritivores?


Give examples of decomposers and detritivores

Photosynthesis: Plants capture energy from sunlight to build organic compounds like glucose from CO2 and H2O. Energy from sunlight is stored in these compounds which make up plant's cells. Compounds can be broken down in respiration to release energy. The energy stored is passed to other organisms as plants are eaten or decomposed.


Plants are producers.


Animals are consumers as they take in organic molecules and break them down in resp. Energy is used for growth and other life processes.


The other means include heat energy in environment. Life processes like movement. Excretion passed on to decomposers. Cannot be eaten and passed to decomposers.


Released to decomposers and detritivores as feed on dead matter and waste material.


Bacteria/fungi are decomposers. Woodlice are detritivores.

Explain Carbon Cycle.



Carbon cycle: Much of the carbon is in molecules in organisms, dissolved in oceans etc. CO2 back to atmosphere. Decomposers release CO2 in resp too. CO2 is added by combustion of fuels.



Explain nitrogen cycle

Nitrogen Cycle:


Nitrogen is part of proteins in all organisms.


Plants can't take up nitrogen from air.


Instead take up nitrogen compounds, nitrates from soil, which are made using nitrogen from air. Called nitrogen fixation


Nitrogen fixing bacteria turns nitrogen gas to nitrates. These bacteria live in soil and inside swellings on roots of leguminous plants.


Swellings called root nodules.


Plants take up nitrates and use them to make proteins. Primary consumers eat, digest proteins and use amino acids to make own animal protein.


Decomposers break down proteins in dead matter.


Releases nitrates back in soil for plants to absorb again.


Nitrogen in waste from excretion also recycled that way.





What do denitrifying bacteria do?


What problems can fertiliser run off in seas cause?

Denitrifying bacteria: Breaks down nitrates in soil and releases nitrogen gas back into air. Known as de-nitrification.


Fertilisers: Run off and cause eutrophication, starving organisms of oxygen. Can't drink it.

Name 4 things Darwin discovered.


What were the cases against him?


What was Lamarck's idea?


Why was Darwin's better than his?



4 things: Evolution. Natural Selection. Variation. Competition and linked with variation. No one had done this before.


Cases against him: Fossils in rocks incomplete. Age of earth not accurately worked out at the time so seemingly not enough time for evolution. Couldn't explain why features were different or passed on to offspring.


Lamarck's idea: Species changed overtime, e.g. giraffes stretching neck and passing it on, but if this was the case, single celled organisms wouldn't exist anymore.


Darwin's was better because it accounted for all observation and links with everything incl. variation and competition.

What is meant by reproductive isolation?


What is meant by monoculture?

Reproductive isolation: Organisms have no contact with neighbours. Sometimes organisms will have variations arise that will prevent them from reproducing with neighbours. Isolated population has therefore become new species.


Monoculture: Growing crops in large fields and harvesting plants at same time.