Ecology - TN Flashcards
Population definition
All of the members of the same species in a particular area
Community definition
All of the populations of living organisms in one area
Habitat definition
A part of the environment that can provide food shelter and a breeding site for living organisms
Ecosystems definition
All the living organisms and the non-living factors in a particular area of the environment
Consumer definition
Organisms that obtain food energy from other organisms
Producer definition
Can convert light energy to chemical energy in food compounds
Quadrat definition
A square that marks or defines an area
biodiversity definition
the number of different species. an area with large populations of few species is not biodiverse
what abiotic factors affect the abundance and distribution of organisms
- light intensity
- temperature
- moisture levels
- soil/water pH content
- wind intensity & direction
- CO2 and O2 concentration
what biotic factors affect the abundance and distribution on organisms
- availability of food
- new predators/pathogens
- out-competition (eg, red and grey squirrels)
definition of an abiotic factor
non-living
definition of a biotic factor
living
in food chains and webs what do the arrows represent
the direction of flow of energy
why is only 10% energy transferred from one trophic level to the next
- some parts of the organism not eaten
rest is used as - heat energy
- life processes
- faeces and remains passed onto decomposers
describe the 6 stages of the carbon cycle
1- plants photosynthesise and carbon atoms form CO2 and become part of glucose molecules stored in the plant
2- some of the glucose broken down in respiration and released into air
3- animals eat plants and respire so carbon gets released back
4- plant/animal dies and decomposers feed on them. they respire and release carbon
5- fossilization occurs on the organisms that don’t decay fully forming fossil fuels
6- fossil fuels are burnt, carbon released
what percentage of energy is transferred to the next trophic level when feeding occurs
10%
give three reasons why the least efficient energy transfer is from the sun to the producer
- some light will miss the plant or its chloroplasts
- come will be reflected by the cuticle
- some has the wrong wavelength to be absorbed by chlorophyll
when plants photosynthesise what happens to the carbon atoms from the carbon dioxide
- they become part of glucose molecules
what do nitrogen fixing bacteria do and where are they found
- in the soil and roots of legume plants
- absorb nitrogen and reduce it to make ammonia = nitrogen fixation
what do nitrifying bacteria do
- convert the ammonia to nitrites and then nitrates = nitrification
why do plants need nitrifying bacteria and why
- plant roots cam ONLY absorb the nitrates
- they are then combined with:
= carbohydrates (from photosynthesis) to form amino acids which are then made into proteins
= and nucleotides which are joined to make DNA
how is nitrogen returned to the soil after being in an animal or a plant
- the animals and plants die and their tissues are decomposed
by decomposing bacteria and fungi - the molecules that contain nitrogen such as proteins release ammonia into the soil
what do denitrifying bacteria do
- some nitrates are converted into N2 in denitrification
why do some nitrogen fixing bacteria live in root nodules of legume plants
- it is a mutualistic relationship - the bacteria receive glucose from the plant, while the plant absorbs the ammonia from the bacteria in the nodule
