B4-Biology

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GCSE Science, B4, C4, P4 Flashcards on B4-Biology, created by ellanabishop on 21/05/2013.
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Flashcards by ellanabishop, updated more than 1 year ago
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Created by ellanabishop over 11 years ago
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Question Answer
why is sampling animal populations sometimes difficult? because they are mobile and not easily visible (usually hiding from predators)
what is one method of sampling animal populations? capture/ recapture methord (LINCOLN INDEX)
what are the 4 stages of the capture/recapture method? 1.capture animals (humanely), number is counted and recorded 2.animals are marked in some way eg with waterproof paint 3.the marked animals are released for a suitable amount of time 4.a second sample is done, some are marked some are not, numbers in each group are counted again
what is the formula for estimating the total population size in a habitat? population size=number in first sample x number in 2nd sample(marked and unmarked / number in 2nd sample marked previously
This method only works when there are 1.no deaths, immigration 2.each sample is taken in exactly the same way 3. the marks given to the animal do not affect there survival rate
what else might environmental scientists want to look at? how species change across a habitat
How is this done? 1.A line (tape measure) laid down with regular intervals marked on it 2.small quadrat laid next to line and number of plants/ species is counted 3.the quadrat is moved along at regular intervals and the plant populations are recorded at each point along the line.
how can these results be presented?
what is zonation? a gradual change in the distribution of species across a habitat eg mussels or periwinkles change in number as you move from low tide up to high tide
what is a habitat? the part of the environment where it lives. A species becomes well suited to it's habitat and sometimes has to compete with other species for limited resources, these can be artificial or natural habitats
what is a community? the total number of individuals of all the different populations of organisms that live together in a habitat
Biodiversity A variety of different species living in a habitat
What is an ecosystem? a physical environment with a particular set of conditions and all the organisms that live in it are affected by the factors present in an ecosystem eg soil type, light intensity
what is usually an ecosystems only external input? sunlight, everything else the ecosystem supports itself on
do natural ecosystems have a high or low biodiversity? high
do artificial ecosystems have a high or low biodiversity? low because they are usually designed for a particular purpose
what is a population? the total number of individuals of the same species that live in a certain area
Name 4 sampling methords 1.pooters 2.sweepnets 3.pitfall traps 4.quadrats
What is a pooter? advantage and disadvantage insects sucked in through a tube, whilst you suck in the other tube. A-no harm caused to insects D-have to be methodical about sampling in order to get good results and its difficult to get idea about numbers
what is a sweepnet? disadvantage net used in long grass or moderately dense woodlands where there is lots of shrubs D-difficult to get true representative particularly in terms of relative number of organisms
what is a pitfall trap? advantage and disadvantage whole in the ground, usually filled with a yoghurt pot to catch small insects as they walk over. D-sometimes water, ethanol, detergent can get into bottom and kill animals A-if enough is used it can give a good representative sample
What is a quadrat? advantage square frame, A-excellent results if placed randomly, population of species can be estimated
Name the photosynthesis word equation carbon dioxide+water---->glucose+oxygen
say the photosynthesis balanced symbol equation... 6CO2+6H20----->C6 H12 O6+6O2
Name 4 things glucose can be converted into 1.starch 2.cellulose 3.nitrates+other nutrients in proteins 4.Lipids(fats or oils) to store in seeds
What is respiration the opposite to? Photosynthesis
Name the word equation for respiration? glucose+oxygen---->carbon dioxide+water
When to plants respire? continuously
What are the 3 factors that affect the rate of photosynthesis? 1.temperature 2.light intensity 3.carbon dioxide concentration
At what temperature do the enzymes controlling photosynthesis start to be destroyed and the rate of photosynthesis declines to zero? 45 oC
When the light intensity reaches a certain point.... it no longer has an effect meaning it is not the limiting factor
when the carbon dioxide concentration reaches a certain point... the rise in carbon dioxide levels now has no effect meaning carbon dioxide is no longer the limiting factor
why is starch a very useful storage molecule? because it's insoluble
Why does plant growth slow down in winter? due to lack of sunlight and warmth
The rate of photosynthesis in a plant can be increased in winter by ARTIFICIAL GREENHOUSES
name 3 things artificial greenhouses are good for? 1.temperature increased by heaters 2.light intensity increased by lamps 3.carbon dioxide concentration increased by chemicals or as by product of the fossil fuel heaters
What is Diffusion? The transportation of substances from an area of high concentration to an area of low concentration >
what controls what substances leave and enter the cell in diffusion? The cell membrane
Name 4 things living cells need to obtain? 1.oxygen 2.glucose 3.water 4.minerals
an example of a waste product a cell doesn't need? carbon dioxide
3 ways the rate of diffusion is increased... 1.the cell membranes surface area is bigger 2.there is a bigger difference between concentrations 3.the particles have a shorter distance to travel
What is osmosis? The diffusion of water from a dilute solution to a more concentrated solution through a partially permeable membrane <
What is a partially permeable membrane? a membrane that only allows certain molecules or atoms through, graded by size
why don't the cell walls affect the movement of water in osmosis? because they are freely permeable
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