Organisms and their enviornment Flashcards
define ecology, community, and enviornment
ecology= the study of living organisms in their enviornment
community= all the populations of all the different species in an ecosystem
enviornment= a unit containing all of the organisms in a community and their enviornment, interacting together
what is a niche
the role of an organism in its natural environment; the way in which it interacts with other organisms and with the non-living parts of the enviornment
what is a food chain and a food web?
food chain= a diagram showing the flow of energy from one organism to the next
food web= a network of interconnected food chains
how does energy loss happen?
- when an organisms uses glucose and other organic compounds for respiration, some of the energy released from the glucose is lost as heat energy to the enviornment
2.when one organism eats eachother, it may leave some left behind. eg. bones
- not all nutrient molecules are digested and absorbed. some just pass through the alimentary canal and are eventually lost from the body in the faeces. the faeces contains energy that is lost in the food chain
what is a trophic level?
the position of an organism in a food chain or web or pyramid of biomass or numbers
what is a pyramid of numbers and a pyramid of biomass?
pyramid of numbers= a diagram in which the area of a bar at each tropic level shows the relative number of organisms at the level in the food chain
pyramid of biomass= a graph showing the relative quantity of biomass at each trophic level
what is a pyramid of energy and how is it created?
its a graph showing the relative quanity of energy at each trophic level.
the researchers work out all the links in the food web, collect samples o each organism. kill and dry it, then burning it to measure how much energy is released
Explain what limits the number of trophic levels in food webs.
The idea that energy transfer
along a food chain is inefficient, energy to decomposers, limited energy
to support another trophic level
why should we understand energy cycles?
so we can determine the most efficient sort of food for a former to grow and us to eat.
what are decomposers and why are they important?
they feed on organic waste material from animals and plants, and on their dead bodies. they help release substances from dead organisms. carbon and nitrogen
what percentage of the air is carbon dioxide?
0.04
what percentage of the air Is nitrogen gas?
78
Define nitrogen fixation
converting insert nitrogen gas into a more reactive form, such as nitrate ions or ammonia
why cant plants and animals use the nitrogen in the air
it is unreactive due to the strong bonds between both nitrogen atoms. it needs to be changed into ammonia (NH3) or nitrates (NO3-)
what are some ways that nitrogen fixation can happen?
lightning. it makes nitrogen gas in the air combine with oxygen, forming nitrogen oxides they dissolve in the rain and wash in the soil, where they form nitrates.
artificial fertilizers= nitrogen and ahydrogen can be made to react in an industrial chemical process, forming ammonia. the ammonia is used to make ammonium compounds and nitrates, which are sold as fertililzers
