Questão | Responda |
habitat | the place where an organism lives including the non living factors aswell as the other species that live there |
species | a group of organisms whose members are similar to one another and can interbreed to produce fertile offspring |
biodiversity | the number and range of different species to be found in the world, the genes they carry and the habitats in which they live |
habitat diversity | the number of different habitats in an area |
species diversity | the number of different species and the abundance of each species in an area |
genetic diversity | the variation of different alleles within a species |
what is the abundance referring to? | the number of species |
what is the distribution referring to? | where the species are found in a habitat |
why must sampling be random | to ensure the data collected is representative |
why must species be identified using a key? | to ensure accuracy |
2 reasons why only a small part of the habitat is sampled | 1)saves time and energy 2)minimise damage done to habitat by taking measurements |
how would you go about measuring the distribution of plants- give one advantage and one disadvantage of this method | -line transect -random starting point -pull line across habitat - all species touching line identified and recorded -ad=immediate impression disad- results are qualitative |
what are the conditions required for measuring the abundance of a plant species with random sampling | uniform abiotic conditions |
how would you go about measuring the abundance of a plant species in a habitat | -random sampling grid up area assign coordinates generate random coords using a table of random numbers place 0.5m2 quadrat on said co ge cords - at least 15 quadrats placed in 5 different areas must be placed -percentage cover is estimated by the number of squares it appears in -quantitative results |
what conditions are necessary for measuring abundance of a plant species using a belt transect | changing abiotic conditions |
how would a belt transect be used to sample plants | a line is stretched across a habitat from a random starting point frame quadrats are placed at regular intervals along the line (every 1m) and percentage cover of plants is measured. |
how would you make a belt transect more reliable? | several transects should be placed parallel to one another (at least 5) |
how may the abundance of flying animals be sampled? | sweep netting and pooter animals are counted and released light trap |
3 ways to sample the distrution of land bound animals | binoculars tullgren funnel pitfall traps |
why are tullgren funnels used? | can be used to force organisms out of leaf litter without having to touch them so they can be counted more easily |
what method could you use to prevent counting the same animal twice and how does it work | mark release recapture method mark using harmless uv paint |
how would you estimate the population trapped after 2 captures? | count from capture 1 x capture 2 -------------------------------- number of marked in second capture |
species richness | the number of different species present in a habitat |
species evenness | a measure of the relative abundance of individuals in each species |
with regards to species evenness and richness, what type of habitat is the most biodiverse | one with a high species richness and a high species evenness |
what is simpsons index of biodiversity? | a formula used to measure the diversity of a habitat.. it considers both richness and evenness |
what does n stand for in simpsons index of diversity | the number of individuals of a particular species.. for a plant this is percentage cover |
what does N stand for in simpson index of diversity | the total number of all individuals of all species |
how would you work out simpsons index of diversity | n -> n/N -> (n/N)^2 sum of all (n/N)^2 take this from 1 |
what does a high value of the simpsons index imply? | high biodiversity, stable habitat- no species dominates habitat- stable food web- extinction unlikely to occur |
what does a low value for simpsons index imply? | not biodiverse- one species dominates- food web is unstable- a change in an environmental factor (eg disease) could cause the extinction of a species from an area |
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