Biodiversity Flashcards
biodiversity
measure of variation found in the living world
habitat biodiversity
range of habitats in which different species live
e.g. woodland meadow streams
species biodiversity
range of organisms found in a habitat
species
a group of organisms that can freely interbreed to produce fertile offspring
genetic biodiversity
variation between individuals belonging to the same species
Sampling and its uses (3)
- Taking measurements of a limited number of individual organisms present in a particular area
- measures particular characteristics and abundance of species
- helps make predictions or generalisations
Random sampling
Selecting individuals by chance, each individual in the population has an equal chance of being selected e.g. randomly generated coordinates
adv: data isnt biased (like selective sampling)
disadv: may not cover all parts of the habitat equally, species with low presence may be missed so underestimate in biodiversity
Non-random sampling
opportunistic, stratified and systematic
Opportunistic sampling (non-random)
Sampling decisions based on prior knowledge eg sampling area with particular species.
adv: easier and quicker than random sampling
disadv: data may be biased, presence of large and colourful species entices sampler, overestimate of its importance and overestimate of biodiversity
Stratified sampling (non-random)
dividing a habitat into areas which appear different and sampling each area separately
adv: ensures all different are as are sampled, species arent underepresented due to missing areas
disadv: may lead to overepresentation of some areas
systematic sampling (non-random)
samples are taken at fixed intervals across the habitat - line and belt transects
adv: useful when habitat shows clear gradient to some environmental factor e.g drier further from pond
disadv: only the species on the line or within belt recorded, underestimate in biodiversity
Different sampling techniques for animals
- Pooter: small insects collected in jar, suitable for low vegetation or water
- Sweep nets: small organisms like insects caught in long nets
- Pitfall traps: small invertebrates and mammals, trap should contain little water to stop escaping
- Tree beating- knock out small animals
- Tullgren funnel: collects small animals from leaf litter, light drives animals down
estimating population size from sampling
- capture a sample of animals
- mark each individual (no harm) this is c1
- release the marked animals
- capture sample on second occasion, this is c2
- the number of already marked animals captured on the second time is c3
- total population = c1xc2
c3
species evenness
measure of how evenly a species is represented (e.g. how many of each species)
habitat with even number of individuals in each species is more diverse than one which individuals of one species outnumber others
species richness
measure of how many different species are present in a habitat
biodiversity measures…
species evenness and species richness
how to measure species richness
counting number of species present in habitat
measuring species evenness
record percentage cover of each plant species
calculate how many animals of each species
calculating overall biodiversity combining species richness and evenness (simpsons index of diversity)
D = 1- sum of (n / N)2
draw table with n column, n/N column and (n/N)2 column.
n= number of individuals of a particular species N= total number of individuals from all species (all n's added)
add up all values for (n/N) to get sum value then minus from 1 to get diversity number
interpreting simspons diversity index values
high value = diverse habitat
small changes in environment affects one species, small proportion of individuals affected, habitat can withstand change
low value = low diversity
small changes can damage the whole habitat e.g. disease or predator
genetic diversity
where more than one allele for a particular locus leading to variations within individuals of same species
why measure genetic diversity
can assess the value of the population as a resource for conservation
calculating genetic diversity
calculate number of loci in one individual that are heterozygous (however does not give good measure of population as a genetic resource)
another measurement involves calculating percentage of loci in population that have more than one allele
polymorphic gene locus
having more than two alleles at a locus, this increases genetic diversity
How can mutations affect biodiversity?
- occur in DNA and creates new allele so increases genetic diversity
How does natural selection affect biodiversity
- species evolve to code for characteristics that code for advantageous characteristics
- less advantageous genes will be lost overtime
- decreases genetic diversity
Factors that affect genetic biodiversity (7)
- Mutations in DNA
- Interbreeding; - individuals from two populations breed and transfer alleles, causes gene flow
- selective breeding- - few individuals in population selected for their advantageous characteristics and bred so can even cause genetic erosion where specific breeds die out
- artificial cloning
- natural selection– species evolve to code for characteristics that code for advantageous characteristics
- less advantageous genes will be lost overtime
- founder effect: when a small sample of original population establishes in anew area, gene pool not as diverse
- genetic drift: chance mutations cause changes in allele frequency in a population from small number of parents. An example is genetic bottleneck caused by catastrophic events
importance of sampling
- impossible to count every individual -sample provides estimate -sample is representative of whole area
Outline the significance of a low value of Simpson’s Index of Diversity
habitat dominated by one/few species
ecosystem / habitat , is unstable / less likely to cope with change
Outline an unbiased sampling method that can be used to measure the biodiversity of plant
species in grassland
1 (use of) quadrat ;
2a random (sampling) ;
3a placing measuring tapes (at right angles) / use grid ;
OR
2b use of transect
3b (quadrat / point frame) placed at regular intervals (systematic sampling)
4 use of identification key
5 method used to determine
abundance - percentage cover
6 repeat many times / idea of considering appropriate
number of samples ;
7 sample at different , seasons / times of year
importance of biodiversity
- Maintains balanced ecosystem as all species are dependant
Human activity that affects biodiversity (3)
- Deforestation
- Agriculture: increases monoculture (crop consisting of one strain of the species so limits genetic diversity)
- Clearing land for housing
- Climate change; human activity increases global warming which means species less able to adapt reducing variation
ecological reasons to mantain biodiversity
when one species is affected by human activity it will affect other species especially with keystone species
keystone species
one that has a disproportionate effect upon its environment relative to its abundance
catastrophic effect on habitat
economic reasons to mantain biodiversity
loss of biodiversity would cuase depletion of soil so less crops
biodiversity allows discovery of medicines
crop pollination
purification of water
detoxification and recycling of waste
conservation in situ
carrying out active management to maintain the biodiversity in the natural environment
examples of conservation in situ
- legislations to stop stuff like hunting logging and clearing land for agriculture
- wildlife reserves: designated areas established for conservation of habitats
how to choose wildlife reserve?
- how many species represented?
- is area large enough to provide long term survival?
- is there a full range of diversity within each species
conflict due to conservation
with local people because:
- protected animals come out of reserve and destroy crops
- people continue to hunt protected animals (poach)
- illegal harvesting of timber
- tourists feeding protected animals or leaving litter
wildlife reserves in UK
- national parks
- NNR national nature reserves
- SSSIs sites of special scientific interest
- marine conservation zones
advantages of in situ conservation
- plants and animals are conserved in natural environment
- permenantly protects biodiversity
- provides oppurtunity for ecologically sustainable land uses
- facilitates scientific research
disadvantages of in situ conservation
- endangered habitats may be fragmented and each small area may not be large enough to ensure survival
- population may already have lost much genetic diversity
- conditions that caused endangerment may be still be present
- area attracts tourists who can cause disturbance
conservation ex situ
conservation outside the normal habitat of the species
examples of ex situ conservation
zoos
botanic gardens
seed banks
conservation in zoos
- breed endangered species
- reproductive technologies like freezing sperm,eggs or embryos preserve genetic material
- artificial insemination, IVF and embryo transfer used
advantages of ex situ conservation
- organisms are protected from predation and poaching - health of individuals can be monitored, medical assistance available - populations can be divided in case of disaster - genetic diversity can be measured - selective breeding to increase genetic diversity - IVF used to increase reproductive success - conservation sites can raise funds as attraction site
disadvantages of ex situ conservation
- captive population likely to have limited genetic diversity - animals exposed to range of diseases - organisms living our natural habitat - nutritional issues can be difficult to manage - correct environmental conditions hard to achieve and may be expensive - hard to reintroduce
botanic gardens uses
ex situ conservation of plants easier than animals bc: - dormant stage of seed seeds produced in large numbers, cn be collected with little disturbance to ecosystem - seeds can be stored and germinated - seeds small so can store more - plants bred asexually - tissue culture increase no. - can be replanted into wild
problems with botanic gardens
- funding camn be difficult, fewer people sponsor plants - collecting wild seeds still causes disturbance - collected samples may not have representative level of genetic diversity - plants bred asexually are genetically identical - reduces genetic diversity
seed banks
collection of seed samples - contain seeds that remain viable for decades -provide seeds for food crops and building materials
storage of seeds
- seeds stored in very dry or freezing conditions to increase viability - essential to test seeds at regular intervals to check viability
conservation agreements
- CITES (convention on international trade of wild fauna and flora) - Rio convention on biological diversity - Countryside stewardship scheme (local scheme)
CITES
aims to ensure international trade of wildlife doe not threaten survival
- ensures trade for commercial purposes prohibited
- regulate and monitor trade
Rio convention on biological diversity
promotes sustainable development, recognises peoples needs as a part of conservation so aims to - conservation of biological diversity - sustainable use of it - shared access to genetic resources - sharing of scientific knowledge
promotes sharing of ex situ conservation genetic material
Countryside Stewardship Scheme
prvides funding to farmers to deliver effective environmental management on land - looking after wildlife and habitats - protecting historic features and natural resources - ensuring traditional livestock and crops are conserved - provide opportunities for people to visit and learn
