4.2)Biodiversity Flashcards
what is biodiversity?
measure of all the diff plant, animal, fungus nd microorganism species, the genes they contain nd ecosystem that they form
What is a species?
A grp of organisms that can interbreed nd produce FERTILE offspring
What is habitat biodiversity?
The range of habitats in which diff species can live
What are the common habitats found in the UK?
Sand dunes
Woodland
Meadows
Streams
How do you tell that one habitat is more diverse than the other when they have the same number of species?
NOT DIVERSE - contain 25 plant species but 1/2 dominate the whole area
DIVERSE - contain 25 plant species dotted fairly evenly in an area
What is {species richness} nd {species evenness}?
Richness - number of species
Evenness - degree to which they are represented
Why is it unrealistic to try and observe + count all species in a habitat?
Estimate suggests that there are billions of single-celled organisms per square meter of soil nd thousands of mites per square meter
What is one way to practically estimate the number of microorganisms in a habitat?
Culture some microorganisms on a nutrient medium in lab nd let them grow
How do you practically sample a habitat?
Select small portion of a habitat
Multiply number of individuals of species found
=
estimate number of individuals of species in entire habitat
What are the 5 types of sampling strategies?
Random (sample site is randomly selected e.g on map)
Non R- opportunistic (researcher samples area that they have prior knowledge on e.g knows that the site contains particular species)
Non R- stratified (dividing habitat into areas that look diff nd sampling them separately)
Non R -systematic (samples taken at fixed intervals across a habitat)
What are the adv & disadv of RANDOM SAMPLING?
✅
-ensures data is NOT biased
👎
-may not cover all areas of habitat equally = species w low presence overlooked = underestimate of biodiversity
What are the adv & disadv of NON-R OPPORTUNISTIC SAMPLING?
✅
-easier nd quicker than random
👎
-data may be biased
-presence of large/colourful species = researches include in sampling data = overestimate biodiversity of that habitat
What are the adv & disadv of NON-R STRATIFIED SAMPLING?
✅
-ensures all areas of habitat is sampled = no under-representation
👎
-e.g disproportionate number of samples in one area = researcher may increase number of samples in lower areas = over estimation
What are the adv & disadv of NON-R SYSTEMATIC SAMPLING?
✅
-shows clear link between the number of individuals of a species nd a environmental factor
e.g further away from pond = drier plants
👎
-only the species within the line/belt can be recorded = other species missed = underestimate biodiversity
what is a sample?
smaller proportion of the target population
what preparation is needed when sampling a habitat?
-suitable clothing + footwear
-apparatus
-appropriate keys to identify plants
-consider the # of samples
-results table
when do you calculate the value of percentage?
when the plants are too small or too many
what is a quadrat?
square frame
how is random sampling completed?
-generate random coordinates
-place quadrat on coordinates
-identify the plants found
-calculate percentage coverage
what is the equation for population size?
of organisms in quadrat X total size of area (sample area) / total area of quadrats
what is a transect used for?
effect of a change in a habitat on biodiversity
what are the 2 types of transects?
-line
-belt
how is a line transect used?
-line drawn through area
-record species touching the line
-fixed intervals
what is an advantage of using a line transect?
able to see the effect of a change
what is a disadvantage of using a line transect?
does not reflect the density of the species
what is a belt transect?
-tape measure with quadrats at fixed intervals
how is a belt transect used?
-quadrats at regular intervals
-identify # of species along the belt
what is an advantage of using a belt transect?
-shows the density of the species in an area
-provide more detailed data
what is a disadvantage of using a belt transect?
the sample is only take in one area of the habitat
why is obtaining quantitative data on animals difficult?
-detect the presence of humans + hide
-run away
what signs can we look for to find the presence of an animal?
-footprint
-droppings
-undigested food
-burrows/dens
-damage to environment
what are some methods of collecting samples of small animals (insects)?
1) sweep netting
2) pooter
3) collecting from trees
4) pitfall trap
5) tullgren funnel
6) light trap
7)longworth trap
how does sweep netting work?
-walk through habitat with sweep net
-sweep animals
what are some adv of sweep netting?
easy
what are some disadv of sweep netting?
insects can fly away
how does pooter work?
use pooter device to suck up insects
what is an adv of using a pooter?
-suitable for low vegetation areas
-cannot run away
what is a disadv of using a pooter?
only one insect at a time
how do you collect small animal from trees?
-place white tree under branch
-knock branch
-vibrations dislodge insects + drop
what is an adv of collecting from trees?
large sample size
what is a disadv of collecting from trees?
animals can run away
how does a pitfall trap work?
-small container used as a trap buried in the soil
-insects fall in
-little water = cannot run away
what is an adv of the pitfall trap?
insect cannot crawl away
what is a disadv of a pitfall trap?
when raining the container can fill up = insect drown
how does a tullgrenfunnel work?
-leaf litter in funnel
-insect attracted to the light
-fall into jar
what is an adv of the tullgren funnel?
cannot fly away
how does a light trap work?
-UV light attracts insects
-collecting vessel with alcoholwh
at is an adv of the light trap funnel?
cannot run away
how does a longworth trap use?
-small mammals
-humane
-monitored regularly
what is one advantage of using a longworth trap?
population size can be calculated
how can you work out the total population of a species?
1) capture sample
2) mark each individual = C1
3) release animals and wait
4) # caught the 2nd time = C2
5) # of animals already caught the 1st time = C3
6) calculate total population = (C1 x C2) / C3
what can affect the estimate calculated?
-animals learn the trap is harmless + contains food
-some don’t like the procedure + keep away
why is measuring biodiveristy important?
make comparisons between different areas and the same area at the same time
what is species richness?
number of different types of species in a particular area
what does species not take into account?
the number of individuals = species with 1 individual carries the same weight as a species with 100 individuals
what is species evenness?
comparison of the size of population of different species within a particular area
what type of data does species evenness produce?
quantitative
when both species evenness and richness increase what happens to the biodiversity?
biodiversity increases
what is needed to compare the biodiversity of an area?
area must be sampled to obtain the number + abundance of species
what is the equation of Simpson’s Index of Diversity?
D = 1 - ∑ (n/N)^2
what is the highest possible value of D in Simpson’s Index of Diversity?
1
what does a large D value show?
-high diversity = pace for many species + organisms
-small change to environment = affect only a small part = habitat is stable + withstand change
what does a small D value show?
-low diversity = habitat dominated by a few species
-small change could destroy the whole habitat
what does assessing genetic diversity help with?
assess the value of the population as a resource for conservation
what is a simple assessment for genetic diversity?
look at features of individual = feature show variation = genetic diversity
where is genetic diversity found?
more than one allele for a particular locus (position on gene)
what does genetic diversity lead to ?
variation between individuals = easily observable = more genetic differences
what is the equation for calculating genetic diversity?
P = number of polymorphic gene loci ÷ total number of loci investigated
why is it hard to estimate biodiversity?
impossible to now how many species have not been discovered
what are the human activities that have led to a decrease in biodiversity?
-change in environment
-alter ecosystems for food
-pollute atmosphere
-destroy habitats
-use resources
what are the effects of agriculture on biodiveristy?
-clear natural vegetation = reduce size of habitat + population = reduces genetic diversity = cannot adapt to change in environment = extinct
what are other issues that affect biodiversity?
-monoculture = only breeding one strain of species
-selective breeding = only using particular traits = reduces genetic diversity
-genetic erosion = loss of genes + reduced genetic diversity
define genetic erosion
loss of genes + reduced genetic diversity
how does climate change affect diversity?
-low genetic diversity = less variation = lass able to adapt to change + evolve
why are migrations going to become more commonplace?
move to climates they are more suited to
what are some obstructions to migration?
-major human development
-agricultural land
-large bodies of water
-mountain ranges
why are domesticated plants + animals at higher risk ?
-little genetic variation = not able to adapt to change
-selectively bred them to provide the best yield
when does extinction occur?
last living member of a species does + species ceases ot exist
what do many scientist believe that human activity is causing?
the start of a great mass extinction
