4.2.1 Biodiversity Flashcards
biodiversity definition
range of habitats, number of different species, and their relative abundance, and the genetic diversity within a species within an area
habitat definition
where an organism lives
species definition
a group of organisms similar in appearance, physiology, and genetic whose members are able to interbreed to produce fertile offspring
habitat diversity definition
range of habitats in which different species live within an area
examples of habitats
sand dune
woodland
meadow
stream
species biodiversity definition
number of different species living in a habitat (species richness) and their relative abundance (species evenness)
genetic biodiversity definition
variation between individuals of the same species
why sampling is necessary to measure biodiversity in an area
too time-consuming to count entire population
allows estimation for entire habitat
needs to be representative of entire habitat so sample range of species in habitat
random sampling method
divide area into map/grid
use random number generator to create coordinates and sample area
take enough samples so data representative of habitat
types of non-random sampling
stratified
systematic
opportunistic
opportunistic sampling features
prior knowledge of site determines sample site
may deliberately sample area where you know organism is present
opportunistic advantages
quicker than random sampling
opportunistic disadvantages
may introduce bias
if sampling area known to have organism, overestimates its abundance/biodiversity generally
stratified sampling features
specifically sampling areas in a habitat that seem very different
stratified adv + disadv
no under representation of any areas (all different areas sampled)
areas overestimated if too many samples taken in proportionally smaller areas
systematic sampling features
samples taken at regular, predetermined intervals across habitat
uses belt/line transect
systematic advantages
line transfer shows how gradual change in an environment factor affects different plant species
systematic disadvantages
species that don’t fall on line may be missed out (underestimation of areas biodiversity, sample doesn’t become representative)
sampling technique for plants
place quadrat on sample sites (depends on sampling method
identify
plants in quadrat using key
measure/estimate abundance of each species
ways of measuring / estimating abundance of a species
abundance scale (ACFOR) estimate percentage cover measure percentage cover using point frame
point frame
frame with 10 needles
place down 10 times on quadrat
each plant touching pin has 1% cover
ACFOR
Abundant Common Frequent Obvious Rare not very quantitative, very subjective
model answer for method of sampling plants
choose sampling method and select areas to be sampled
place quadrat
identify plant species in quadrat (using key)
record presence/absence of each species in each quadrat
estimate percentage cover (using point frame)
repeat to show repeatability and to identify anomalies
extrapolate data to estimate biodiversity
sampling animals facts
animals move so need to be trapped (smaller animals) or sampled visually (larger animals without trapping)
equipment needed when sampling habitat
suitable clothing and footwear for habitat
sampling apparatus
clipboard, pens and paper to record observations
keys appropriate to area to identify organisms
camera/smartphone to record specimens and grid location
mark-and-recapture technique
capture sample of animals mark each individual in harmless way (C1) release marked animals capture another sample (C2) number of already marked animals = C3 population estimate = (C1xC2)/C3
factors affecting population estimate found using mark-and-recapture
animals learning trap is harmless and contains food
animals not liking experience and keep away from traps after first capture
pond/sweep nets
sweep nets in wide arcs to catch animals
identify and count on white background
used for small animals/insects living in water/low vegetation
pooter
sucks up animals into small container to stop them flying away
used for small animals/insects once caught in sweep nets/from trees
from trees
hit tree branches with stick to knock off animals into white tray/paper to identify and count
used for small animals/insects in trees
pitfall trap
container buried in soil (just below soil), small animals / insects fall into it
water / stunning chemical used to stop them crawling out
should be sheltered in rain
used for small animals / insect on ground
Tullgren funnel
leaf litter placed on mesh
light dries out leaf litter
animals go down, fall through mesh into a collecting jar
small animals / insects from leaf litter
light trap
UV light attracts insects which fall into alcohol in trap
insects attracted to light at night
Longworth trap
bait put in trap, snaps shut behind animals
leaves animal unharmed
can be marked, released and recaptured to estimate population size
trapping small animals e.g. mice
surveying frequency of plants
use similar sampling method as before (quadrat)
calculate percentage cover
measuring density of animals in a habitat
larger animals = observation
smaller animals = mark-and-recapture technique
tiny animals in soil = count individuals
animals in water = net to sift through body of water and mud then count
Simpson’s index of diversity (D)
measure of diversity in a habitat
takes into account species richness and evenness
D = 1 - (sum of all (number of one species/total number of all species in the habitat)^2)
Interpreting Simpson’s index of diversity
close to 1 = more biodiversity in habitat
suggests habitat is home to wide variety of different species
changes to one species won’t impact many individuals (in proportion to total number of individuals)
further from one = less biodiversity in habitat
suggest habitat dominated by few species
small change to one species could damage or destroy whole habitat
measuring genetic diversity
more alleles of one locus = more observable variation between individuals in a same species
calculate percentage of polymorphic gene loci
polymorphic gene loci
have 2 or more alleles
locus definition
position of specific gene on chromosome
human factors for biodiversity
human population growth
agriculture
climate change
how human population growth affects biodiversity
clear out land for farming
extract and use natural resources (destroys habitats) e.g. hunting/fishing, fossil fuels
burning of fossil fuels for more energy (pollution)
how agriculture affects biodiversity
monoculture: reduces genetic biodiversity (only one strain of species), crops more likely to die out of habitat factors suddenly change
selective breeding: reduces genetic biodiversity as ignores other traits in place for a select few desired traits, specific breeds become rare or die out
land cleared out for farming space
genetic erosion definition
loss of alleles, reducing genetic diversity of species
monoculture definition
when only one strain of a crop is farmed
makes harvesting of crops easier and cheaper
how climate change affects biodiversity
changes in temperature and rainfall, caused by human activity
species with low genetic diversity may go extinct (unable to adapt)
may be forced to migrate (not always possible)
diseases may migrate, harming other ecosystems
monocultures (low genetic diversity) won’t be able to survive
extinction definition
when the last living member of a species dies so species ceases to exist
reason to maintain biodiversity
ecological reasons
economic reasons
aesthetic reasons
ecological reasons for maintaining biodiversity
plants form habitats for other organisms interdependence (loss of one species affects other species, part of food chain in ecosystem) keystone species (have disproportionate effect on habitat relative to population size) genetic resource for genetic engineering, selective breeding, medicine
economic reasons for maintaining biodiversity
plant biodiversity encourages recycling of nutrients in soil , better ability to grow crops
monocultures deplete soil
deforestation can cause flooding (damages crops/buildings)
wood used for furniture making
could be a tourist attraction
could be a source of medicine/scientific research
conservation ex situ definition
conserving an endangered species by activities that take place outside its normal environment
when conversation ex situ is necessary
natural habitat destroyed/under threat by climate change/human activity
population in natural habitat very low
if reproduction in wild is difficult (low numbers)
breeding programmes allows increase in population size of species
how conservation ex situ helps conservation of plants and animals
breeding ex situ maintains genetic diversity (if done properly)
allows protection from competition, grazes/poachers
allows protection from diseases
how to set up captive breeding programmes for animals
collect animals from several different locations
increases genetic variation if geographical variation maintained
reduces risk of inbreeding, of losing all individuals to specific disease
minimise stress during capture and captivity
zoos have data on which individuals are related
zoos can exchange sperm and artificially inseminate for lower likelihood of inbreeding, better genetic variation
advantages of ex situ for animals
health can be monitored, diseases treated
young hand reared (lowers chance of mortality of young)
provision of breeding mates controlled
protection from diseases, predation, hunting
competition reduced between individuals
disadvantage of ex situ for animals
expensive often don’t breed successfully (captive stress, no compatible mate, altered breeding cycle) space limited (limit number of individuals, less genetic diversity and variation, may lead to inbreeding) may be difficult to reintroduce species to wild
why reintroduction of species into wild may be difficult
animals too tame (not afraid of humans/poachers)
unable to reintegrate to wild population
difficult to find food for themselves
may face predation
habitats may be destroyed
conservation in situ definition
conserving a species in its normal habitat and attempting to minimise human impact on natural environment and protecting natural environment
measures to help preserve species in wild
ban hunting create protected reserves proving breeding sites prevent habitat destruction monitoring species with tagging feeding programmes educate tourists on not feeding wild animals, not dropping litter promotion of ecotourism (generate money to help preservation, create sperm + egg banks)
advantages of in situ
cheaper than ex situ (conditions + food required fir survival may already be present)
species already well adapted to habitat
no special previsions needed to be made
can create protected reserves
advantages of protected reserves
can ensure sustainable use of environment (land and resources)
allows for scientific research of ecosystem
permanently protects biodiversity in area
creates areas of interest for tourists
disadvantages of conservation in situ
threats to survival of species may be present
human activity may threaten species (e..g hunting, deforestation)
disease could threaten survival of species
species could be outcompetes by other species
CITES and its aims
Convention on International Trade in Endangered Species of Wild Fauna and Flora
prevent trade of endangered species
ensure trade doesn’t endanger wild populations
prohibit commercial trade in wild plants
allows some trade of less endangered plants and animals
allow trade in artificially propagated plants
how CITES helps to save endangered species
countries in agreement make poaching illegal
ban trade of endangered species
increase cooperation between countries
increase awareness of impact of illegal trade
Rio convention on Biological Diversity
International agreement by 150 governments
promotes sustainable development
recognises human needs for food, medicine, land, clean environment as well as maintaining biodiversity
Rio convention of Biological Diversity aims
sustainable use of organisms/habitats/ecosystems
share genetic resources and access to scientific knowledge
promoting ex situ conservation methods
international cooperation of biodiversity issues
raising profile of biodiversity with governments / general public
advantages of seed banks / botanic gardens
seeds collected from wild population won’t impact wild population too much (as produced in large numbers)
seeds stored in protected surroundings
compact so can be stored in large numbers
plants can breed asexually
can be used for research or reintroduction to the wild
disadvantages of botanic gardens/seed banks
may be difficult to fund publicly
collecting wild seeds always causes some disturbance
collected samples may not have representative level of genetic diversity
seeds collected from one area genetically different from another area, may not succeed in different areas
seeds stored for long time may not be viable
asexual breeding reduces generic diversity (genetically identical offspring)
research done on small sample may not be valid for whole species
how seeds stored
very dry / freezing conditions
regularly checked if seeds can germinate (as they deteriorate over time)
Countryside Stewardship Scheme
introduced in England 1991
applied to land not to be in an environmentally sensitive area
paid farmers to enhance and conserve English landscapes
Countryside Stewardship Scheme aims
improve natural beauty and diversity in countryside
enhance, restore and recreate landscapes, wildlife habitats and historical features
improve opportunities for public access
Environmental Stewardship Scheme
replaced CSS in 2005
funds and advises farmers and other land managers to environmentally manage their land
Environmental Stewardship Scheme aims
converse, enhance and promote countryside by:
look after wildlife, species and habitats
retain traditional character of land
protect historic features and natural resources
traditional livestock and crops conserved
opportunities for people to visit and learn about countryside
