4.1.2 biodiversity Flashcards
(30 cards)
importance of maintaining biodiversity
many drugs orginate from plants and microbes. by maintaining biodiversity it increases the chances of finding more new drugs. we need to make sure we maintain a genertic resource for the future. many modern drugs are made using knowledge of traditional remedies. once a species is extinct, its genetics and potential medicines would be lost forever
what is species biodiversity
the number of different species and individuals within each species in a community
what is genetic biodiversity
the variety of genes amongst all the individuals in a population of one species
what is habitat biodiversity
the range of different habitats
what is biodiversity
the variety of life on earth at all its levels, from genes to ecosystems
what is species richness?
the number of different species in an area at a time
what is species evenness?
the distribution of species, the realtive abundance of each different species within the community
how is genetic diversity measures?
calculated using polymorphic genes within isolated populations such as zoos. a polymorphic gene is one that has more than one allele. most genes only have one allele and are therefore monomorphic. the equation is: proportion of polymorphic gene loci = number of polymorphic gene loci/ total number of gene loci. the higher the proportion, the larger the genetic diversity
simpsons index of diversity
used to measure the biodiversity of a habitat. N= total number of all organisms. n= total number of organisms of a particular species. D = diversity index- the probability that two randomly selected individuals will belong to the same species. equation is : 1-(n/N)^2
using simpsons equation, is 1 high or low biodiversity
maximal
why do we sample
to save time and resources. aims to be respresntative of target population
how to random sample a field
sampling sites selected at random. avoids bias. a grid system is set up by laying out two tape measures. random number generator generates coordinates. quadrat placed at each coordinate.
outline non-random sampling techniques
opportunistic: sampling based on availability and convenience. not representative.
stratified: some populations have separates sub strata, when sampling a pond you may take a sample from the surface, the shallow, the deeps. very representative
Systematic: using a belt transect, measuring every x meters. used to examine a change in biodiversity along an area.
what are point quadrats used for
to sample plants and slow-moving organisms. a point quadrat is a horizontal bar with holes along it at set intervals that long pins can be placed through. the pin is pushed through to touch the ground and any species touching the pin are recorded
what is a frame quadrat
a square frame with grids to measure species within.
outline pooter sampling
for small isnects / invertebrates in grass areas. involves sucking on a mouthpiece, insects are drawn into a holding chamber via an inlet tube.
outline sweep net sampling
for insects in long grass, flying invertebrates. involves sweeping the net back and forth in long grass
outline tree beating sampling
for invertebrates living in a bush or tree. involves stretching out a large white cloth under a tree, which is shaken to dislodge the invertebrates which would fall onto the sheet.
outline pitfall trap sampling
for small crawling invertebrates. involves digging a hole in the grounf, and making edge of cup flush with thte ground. place pebbeles around and put cover of top so they don’t drown. leave for a few hours
outline kick sampling
for organisms living in a river or aquatic invertebrates. involves kicking the river bank for a period of time to disturb the substrate. a net is held downstream to capture the organisms
how to measure species evenness
record how many species are present and the individuals within each species. mark recapture method.
factors affecting biodiversity
- human population icrease, we need space for housing, farming for food, industry. all these require deforestation. land clearance for agriculture is destruction of habitats. use of fertilisers etc, use of monoculture.
- climate change is melting polar ice caps, destroys habitats and rises sea levels leading to flooding of coastal habitats
- change means animals aren’t able to survive in the environment anymore
economic reasons to maintain biodiversity
provides protection against abiotic stresses
soil erosion from deforestation reduces ability to grow crops
continuous monoculture = soil depletion
habitat loss means loss of potentially valuable discovery
use of plant varieties for cross breading
conservation or organisms we use to make things
ecological reasons to maintain biodiversity
interdependence of all organisms
keystone species
