Section 8: Ecology and the Environment Flashcards
Define a habitat
the place where an organism lives eg a forest
what is a population?
all the organisms of one species in a habitat
what is a community?
all the different species in a habitat
what is an ecosystem?
all the organisms living in a particular area and all the non-living (abiotic) conditions - eg temp, climate,soil type
what are two downsides/problems with using quadrats to estimate population sizes?
- the sample may not be representative of the population
2. the sample size affects the accuracy of the estimate - bigger sample = more accurate estimate of the total population
what are the first four trophic levels?
producers
primary consumers
secondary consumers
tertiary consumers
what does each bar on a pyramid of numbers represent?
the number of organisms at that stage of the food chain
what does each bar on a pyramid of biomass represent?
the mass of living material at that stage of the food chain
what do pyramids of energy show?
the energy transferred to each trophic level in the food chain
what are some ways in which the energy ingested isn’t completely taken in? (in fact 90% is lost)
- some parts of the food are indigestible so pass through the organism and come out as waste
- a lot of the energy taken in is used for staying alive, eg in respiration
- a lot on energy is lost to the surroundings in heat
what is the energy that is transferred from one trophic level to the next?
biomass - stored or used for growth - is transferred
where does all the energy for CO2 production come frm?
photosyntheses
what do green plants use the carbon from CO2 in the air for?
to make carbohydrates, fats, and proteins
what happens in terms of the carbon cycle when plants and animals decompose?
they’re broken down by bacteria and funghi. these decomposers release CO2 back into the air by respiration as they break down the material
