biodiversity Flashcards
3 levels of biodiversity
- genetic
- allelic variation within a species - habitat
- no. of different habitats in an area - species
- no. of species in an area
population
total number of individuals
species
group of organisms that can interbreed and produce fertile offspring
habitat
an environment in which a particular species lives
biodiversity
the variety of life within an area, including both biotic and abiotic factors
sampling general
- taking measurements of a limited number of individual organisms present in a particular area
- carried out when it’s difficult to count every single individual
- produces a representative estimate of a whole area
random vs non-random sampling
random
- every element has an equal chance of being picked
- sampling frame required
- elements selected randomly
non-random
- elements are picked according to a system
- elements have different chances of being picked
3 types
- opportunistic
- stratified
- systematic
random sampling
- allocate a number to each element
- use a random number generator to generate numbers
/
avoids bias
easy
fast
X
difficult for large populations
less representative
systematic
- population grouped within itself
- different areas identified
- each area sampled separately based on a system i.e. every 3rd element
/
simple
suitable for large samples
X
can introduce bias
stratified
- population divided into groups
- random sample taken from each stratum proportional to the size of the group
/
reflects population structure
proportional representation of groups within the population
X introduces bias more resources required the population must be divided into groups difficult with larger populations
opportunistic
- sample picked based on availability/accessibility as long as they fit specific criteria
/
easy
fast
suitable for large populations
X
bias
not representative
PLANT sampling techniques
- quadrat
grid using a tape measure, place quadrat at coordinations calculate the number of plants or percentage cover (use a key to help identify plants) - transect
belt or line (shows change in areas well)
use a tape measure as a transect, count the number of organisms touching the line - point quadrat
sampling frame
holds vertical pins, record the number of times the pin “hits” the organism being investigated
ANIMAL/INSECT sampling techniques
- sweep net
in tall vegetation
hold sweep net and move side to side in an arc
count no. of organisms collected - pooter
insects
the jar used to collect insects, apply suction on one side and insect drawn in on other - pitfall trap
ground surface organisms
a device, such as buried beaker, traps insects and small animals which are then counted - tullgren funnel
extraction on invertebrates from the soil/ litter
the sample is placed in the funnel above disc, placed under light, heat dries the sample, animals fall into the beaker
why measure biodiversity?
measuring biodiversity gives a baseline to test the effects of human activity, climate change and disease
Simpson’s index
D = 1 - (sum of (n/N)2^)
D = biodiversity n = number of organisms of specific species N = total number of organisms of all species
LOW = dominated by 1/ few species, low species richness and evenness, an unstable ecosystem which is less likely to cope with change
HIGH = many species, not dominated, high species richness and evenness, a more stable ecosystem
species richness
no. of different species in an area/ habitat
species evenness
the relative abundance of individual species in an area
agriculture
monoculture
- reduced variation, affects soil richness
- increased dependence on herbicides + fertilisers
/
crop rotation
legumes - secrete nutrients into soil
pesticides/herbicides
- kills pest species
- reduces dependant species
deforestation
- reduces habitat diversity
- vegetation/ food source loss
= species diversity decrease
population growth
land is lost to accommodate growing population and provide sufficient services, facilities and transport, e.g. road building = decrease in habitat and species diversity
more people, more fossil fuels burnt = global warming, climate change = migration of species, flooding/damage to habitats
climate change
global warming - melting ice caps, flooding - extinction of species that live in extreme conditions - migration of species - habitat damage/loss - land loss - food resource decrease - extreme weather/ rainfall = nutrients washed from soil, poor soil richness which limits the growth of vegetation = decrease in biodiversity
benefits of plant diversity
- medicine
- increases genetic variation
- potential genetic resourcce
- selective breeding/ genetic engineering
- agents for biological control
benefits of animal diversity
- vital for life
- evolution
aesthetic reasons for maintaining biodiversity
- tourism
- enriches lives
- potential medical cure
- protect landscapes
economic reasons for maintaining biodiversity
- tourism
- plant-derived products i.e. rubber, coffee
- protection against abiotic stresses
- plants are source of food, drink, clothes, fuel, materials
- medicine
- scientific research
ecological reasons for maintaining biodiversity
- disruption
- interdependence
- conserve keystone species (in proportional affects on the environment, maintain and support ecological community)
in-situ conservation
inside organism’s natural habitat
maintains genetic diversity
preserves interdependent relationships
- marine zones; protect species-rich areas e.g. coral reef
- wildlife reserves; controlled grazing, restrict human access, remove invasive species, feed animals, controlled poaching, reintroduce species
ex-situ conservation
outside organism’s natural habitat
protection from predators, poaching, herbivores
controlled health
- botanic gardens; provides plants with best growth conditions
- seed banks; stores genetic material
- captive breeding; produce offspring in human-controlled environment/ reduce/ prevent extinction
CBD/ RC
convention biological diversity/ Rio convention
- countries develop national strategies for sustainable management
- maintain biodiversity sustainably
CSS
countryside stewardship scheme
- government grants landowners money to improve and extend wildlife habitats and conserve wildlife and biodiversity
- promote land management techniques to landowners
CITES
convention international trade endangered species
- ban the trade of wildlife plants
- allows the trade of less endangered species
- regulates/monitors trade of endangered species
- allows the trade of artificially propagated plants
seed banks
seeds dried, stored in low humidity and in temperatures below 20 degrees = maintain viability
seeds checked at regular intervals
why?
genetic resource
potential medical uses
provide back up in case of extinction
/ little space large numbers stored viable for long time less susceptible to disease/ pests
EIA’s
environmental impact assessments
- predicts positive/ negative effects of project on biodiversity of an area
