Flashcards in Biodiversity Deck (55):
What is Biodiversity?
the variety of species in an area
range of different habitats
What is habitat biodiversity?
the range of habitats in which different species live
What is a habitat?
where an organisms lives
What is a species?
a group of organisms that can that can interbreed to produce fertile offspring
What is genetic biodiversity?
the variation between individuals belonging to the same species
what are the three different kinds of biodiversity
what is species biodiversity?
the range of organisms found in a habitat
What is sampling?
studying a small proportion and multiplying it to get a whole habitat
What is a method to sample animals?
1. Look for signs that they have left behind for example footprints, droppings, borrows and nests – droppings can be distinguished by using DNA
What are the different ways to catch invertebrates?
sweep netting, collecting from trees, tullgren funnel, light trap, pitfall trap
How does a sweeping net work?
walking through the habitat with a tout net while sweeping the net through vegetation in wide sweeps. Small animals (insects) will be caught in the net. Then empty the content on a white sheet and identify the animals making sure they do not fly away. To stop them flying away use a pooter
How does collecting from trees work?
spread a white sheet under a branch and knock the branch with a stout stick, this would cause the small animals to fall and then identify them before they fly away
How des a Tullgren Funnel work?
this collects small animals from leaf litter, the lead litter is placed in the funnel and the light above the litter drives the animals downwards, they then fall through a mesh screen to be collected in a jar underneath the funnel
How does a light trap work?
this is used to collect flying insects at night, the ultraviolet light attracts the insect, they then fall into the vessel containing alcohol underneath
How does a pitfall trap work?
this is a small container buried in the soil so its rim is below the surface, therefore any animals moving through the soil will fall into it. To stop the animals crawling out again put a little water in it.
How do you trap small animals?
They can be trapped using a longworth trap (this does not harm the animal) therefore allows the population size to be calculated
How does a longworth trap work?
1. Capture animals
2. Mark them in a way that doesn’t cause harm
3. Release the marked animals and leave traps for the next time
4. The number of marked animals on the second occasion is C2, the number of already marked animals on the second occasion in C3
5. Total population
What is the estimate affected by?
The estimate is affected by the animals that learn the trap is harmless and has food or by those that don’t like being trapped and therefore keep away
How do you measure species richness? and what is species richness
count all the species
the number of different species present in a habitat
How do you measure species evenness?
carry out a quantitive survey
How do you measure the density?
calculate how many animals of each species there are per unit area
What is simpson's index?
What does a high value of simpson's index equal?
what does a low value of simpson's index suggest
a high value = diverse habitat
A low value = this suggests that there is low species evenness and therefore one species may dominate, they have a low ability to withstand change and therefore the environment is not stable and at risk
Why is a high diverse habitat stable?
a small change in the environment which effects one species then other species wont be as effected due to a more complex food chain therefore the overall effect is small
what does assessing genetic biodiversity help do?
helps assess the value of population as a resource for conservation
How do you measure genetic biodiversity
look at features of species and see if they vary in the population or between population
How do you calculate biodiversity
calculate the percentage of loci in a population that have more that one allele
What are the reasons to maintain biodiversity?
feed the world
provide more and better medicine
provide life support for our biosphere
food web disruption
satisfy human curiosity
provide natural beauty
respect life in all its forms
What is a keystone species?
a species that has a disproportionately large effect on the environment
What is interdependence?
established communities of animals and plants are interdependent and rely on each other to survive
beaver example for keystone species?
chops down trees allowing light to reach other plants and increases biodiversity as new plants grow
they build dams this makes the river rise and new aquatic plants grow
increases insects to feed on plants
increases large animals to feed on insects
otter example for keystone species?
otters feed on sea urchin,
sea urchins feed on kelp
if the otter did not eat sea urchins then population would rapidly increase and the kelp population would decreases, other animals would die out as there is no food and the ecosystems become inhabitable
same plant - same minerals therefore it depreciates the soil of minerals
fertilisers replace the minerals but are harmful to animals
unmanned ecosystems have minerals replaced naturally
How does biodiversity help feed the world?
without a biodiverse plant species disease or natural disasters could wipe them out therefore resulting in famine
how does biodiversity provide life support for our biosphere
e.g. forest absorbing carbon dioxide
How does biodiversity maintain economies
wipe out= financial hardship
regulating atmosphere and climate
purification and retention of fresh water
formation and fertilisation of soil
detoxification and recycling of wastes
growth of timber
why has the human population grown in size?
- better medicine
- better ways of doing agriculture
what effect are humans having on the world?
- they alter ecosystems to provide ourselves with food
- we destroy and fragment habitats
- we use more of earths resources
- we pollute the atmosphere
How does agriculture affect biodiversity?
- we clear vegetation reducing the size of habitats and the population size of those animals living in the habitats, this reduces the genetic biodiversity of the species as their population is decreased therefore the species has less chance of adapting to changing conditions through evolution
- isolated and fragmented populations that are too small to survive
How does monoculture affect biodiversity?
monoculture is a crop consisting of one strain of species this means that it has low genetic biodiversity
+ makes crop easier to harvest
- rainforests which have high natural genetic and species biodiversity are cut down and replaced with a species which has low genetic biodiversity
How does selective breeding affect biodiversity?
- reduces genetic biodiversity as farmers select particular characteristics which mean that other traits are ignored, therefore decreasing the genetic biodiversity
- breeds become rare and die out this process of decreasing biodiversity is known as genetic erosion
+ best yield in specific climate
How does climate change affect biodiversity
species who now have less genetic biodiversity and are therefore less able to adapt to the changing climate
- therefore they have to migrate in order to follow the climate patterns which suit them the best
- there are things stopping the migration such as human developments, agricultural land, large bodies of water, mountain ranges
what are the main things that affect biodiversity?
agriculture - monoculture and selective breeding
what is particularly at risk from climate change?
domesticated crop plants and animals as they have been adapted in selective breeding therefore have a low genetic biodiversity therefore will find it hard to adapt to the changing climate and are vulnerable to disease
when does extinction occur?
when the last member of a living species has died and therefore the species ceases to exist
- the rate of extinction is 100-1000 times the rate of which is usually is
- half species that are around today could be extinct by 2100
- the extinction rate is at least as fast as in any previous extinction rate
What are the types of sampling?
non-random - opportunistic, stratified, systematic
How is random sampling carried out and what are the advantages and disadvantages
- sample sites inside the habitat are randomly selected, you do this by deciding where to take sample before you study the area in detail - randomly generated numbers, or satellite system to randomly select
+ not biased
- may lead to an underestimate of biodiversity as not every area is covered
How is opportunistic sampling carried out and what are the advantages and disadvantages?
- this is when the researcher makes sampling decisions based on prior knowledge or during the process of collecting data, the researcher might deliberately sample are area that contains a particular species
+ quicker and easier than random sampling
- overestimate of biodiversity as large or colourful species may attract the investigator
How is stratified sampling carried out and what are the advantages and disadvantages?
-dividing a habitat into areas which appear to be different and sampling each area separately
+ ensures all areas of a habitat are sampled and species are not under-represented due to random sampling missing areas
- over representation in some areas due to Add to disproportionate number of samples taken in small areas that look different
How is systematic sampling carried out and what are the advantages and disadvantages?
- when samples are taken at fixed intervals across the habitat - belt or line transects
+ useful when habitat shows a clear gradient such as an environmental factor
- only species on the line or within the belt can be recorded other species may be missed leading to an underrepresentation of biodiversity
What is the positive of wild plants and animals to agriculture
Can breed therefore higher genetic biodiversity
Can breed to prevent certain diseases
Natural predators to pests
How to answer that stupid 5 mark question
- same technique used in each habitat, repeat the experiment in each habitat, use random sampling to reduce bias, record the organism that you collect using a suitable method
name method that you use for sampling
- take samples at different times of the year
What is the importance of sampling
- sampling provides an evidence
- sampling provides an representative
- difficult to count all individuals
why are both species richness and evenness needed to assess biodiversity
- both species richness and species evenness are needed to reveal dominance
- high biodviersity is done by high species richness and high species evenness