Biology- classification and biodiversity

what is biodiversity

the variety of living things in an ecosystem or habitat

what is a habitat

the place where an organism lives

what is genetic diversity

the variation of different alleles within a species

what is a population

number of individual species in one area

biotic factors

living things in a habitat

abiotic factors

non living things in a habitat

what is a niche

the role of an organism in its habitat

what is habitat diversity

number of different habitats in an area

what is species diversity

the number of species in an area and their abundance

what is species richness

number of different species in a community

what is species evenness

the relative abundance of each species in an area. the smaller the range the greater the evenness

how do we sample using a quadrat

draw a map of the area and draw a grid with co ordinates over top. use a random number generator to generate your co ordinates. this is to prevent bias it is called random sampling. go to those co ordinates and place a quadrat in that area. identify species using a photo key and either count the number of species in that area or count their percentage cover of the quadrat. repeat a minimum of 30 times and calculate the mean abundance per quadrat. finally multiply by the area of the habitat to give an estimate

what is the ACFOR scale

we use this when sampling, it gives us qualitative data. the person lists a species as Abundant, Common, Frequent, Occasional or Rare

when do we use non random sampling

if we want to see how certain factors affect species abundance, diversity or distribution

What is systematic sampling?

when samples are taken along regular intervals often along a line, quadrats are placed from one area to another e.g. shaded area to an open area

whats a line transect

making a line along the ground and taking samples at specific points, you identify the organisms that touch the line

What is a belt transect?

provides more information, 2 parallel lines are marked and samples are taken in the area between the two lines usually using a quadrat.

what is opportunistic sampling

when samples are chosen by the investigator. it gives a bias unrepresentative result but it is very simple and quick

what is stratified sampling

when different areas in a habitat are identified and sampled separately depending on their proportion to how the occur in the real habitat. this is very representative

types of non random sampling

opportunistic, stratified and systematic sampling

why is it harder to sample animals

- they move so may leave the quadrat

- you may count the same animal twice

- ethical issues with catching them due to stress

what is a pitfall trap and why is it used

it traps crawling insects, it is a hole in the ground that insects fall into and cannot get back out of so you can count them

what is a pooter and why is it used

it is a bottle like structure that allows you to safely suck insects into a jar to count and collect them

what is a tullgren funnel

a mesh filter is placed above leaf litter with a light source pointing on it. this light dries out the litter and causes insects to move away from it, falling into the beaker. mainly used for organisms in soil

what is kick sampling

this is mainly used for aquatic animals. you will stand upstream of a river and gently disrupt the seabed by kicking it. then you will go downstream with a net to collect the free organisms

what is a sweep net

for organisms in long grass you walk across a row of grass, hedges or crops and sweep left and right through it you quickly the sweep up the net to collect the organisms into a tray

control when sampling different habitats?

always use the same type of sampling trap, e.g. always a pitfall trap

what type of animals can you sample with a quadrat

slow moving animals like slugs and snails.

What is Simpson's index of diversity?

A measure of the diversity of a habitat. the value is always between 0-1 and the closer to 1 it is, the more diverse that habitat is.

what is a polymorphic gene

a gene with 2 or more alleles. they create more genetic diversity

calculating genetic diversity

proportion of polymorphic gene loci= number of polymorphic gene loci / total number of loci

why is it bad for there to be low genetic diversity

if there is a new selection pressure that arises e.g. a new disease then the chance of the population dying out is high due to them all sharing the same genes, if one cant survive the rest wont. this is seen in zoos and is a=managed very carefully

how does human population growth affect biodiversity

if there are more people then theres more deforestation. this is to clear way for houses, roads, shops or to collect raw materials like timber, also more people means more food. more land is cleared for farms. most of these farms only have 1 type of crop on further decreasing biodiversity. increased people means increased cars which means more sulfur dioxide released which means more acid rain so more organisms die

how does agriculture affect biodiversity

farmers usually only have a few types of crop. crops are also usually selectively bred to increase yield, this leads to a hugely reduced genetic diversity. increased need to farm means increased land cleared for farms. hedgerows (where many species live) removed to allow large machinery to fit into fields. farmers used herbicides, pesticides, insecticides so kill more species. decrease in plants and insects means a decreased food source for other animals and then they die. increased farm machinery= increased soil erosion= decreased biodiversity

How does climate change affect biodiversity?

melting ice caps lead to extinction of species on the ice caps. sea levels rising means floods in lower areas where species live. saltwater also flows more upstream so less freshwater species live. increased temp= decreased rainfall= plants wont survive and xerophytes will become dominant. this decreases food sources for many animals killing more species. if climate change is slow some species however may adapt and survive or migrate to better areas

3 reasons we maintain biodiversity

economical, ecological, aesthetic

Ecological reasons for maintaining biodiversity

1. protect species, 2. maintain genetic resources

why do we need to protect species

organisms are interdependent- they rely on other organisms to live such as plants and keystone species. the loss of one species may be detrimental to the ecosystem. this is mainly seen in keystone species. without keystone species the ecosystem will drastically change and may not recover

What is a keystone species?

a species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically.

example of keystone species

sea otter

why do we need to maintain genetic resources

keeping genetic resources allows food, drink, clothes, materials and drugs to be made. without the genetics of other organisms we may not live how we do today. they allow us to adapt to changes in the environment e.g. climate change causes drought so we genetically engineer our crops so theyre resistant and survive

economical reasons to maintaining biodiversity

1. maintain global economy, 2. crop growth, 3. prevent soil depletion

why do we maintain global economy

many products produced from plants and animals are traded on a global scale. if raw materials are lost industries would collapse, areas rich in biodiversity also attract tourists

why do we maintain crop growth

deforestation results in soil erosion which reduces a countries ability to farm. they will need to rely on other countries

why do we need to prevent soil depletion

monoculture involves growing one type of crop continuously. this causes the soil to lose its nutrients as theyre used up by the crops. more fertilisers need to be used and yields are decreased

Aesthetic reasons for maintaining biodiversity

different plants and animals in our environment make us feel better. studies have shown how recovering from stress/injury is quicker when surrounded by plants. also this attracts tourists

what is conservation

maintenance of the environment and its natural resources. it protects endangered species

what does extinct mean

no longer existing anywhere in the world

what does extinct in the wild mean

organisms of the species only exist in captivity

types of conservation

in situ and ex situ

what is in situ conservation

Conservation within the natural habitat

what is ex situ conservation

Conservation out of the natural habitat e.g. zoos

examples of in situ

wildlife reserves

what does in situ conservation do

it protects species from urban development. it allows organisms to live in their natural habitat whilst restoring endangered species. species can be protected and legal protection can be given e.g. fishing quotas

what does ex situ do

this can be relocating species to less dangerous areas eg. rhinos moved from the congo to kenya due to poachers.

it can be breeding organisms in captivity and releasing them into the wild

it can be botanical gardens where rare plants are grown and seeds are stored for conservation and research

can be seed banks

why doesnt captive breeding always work

animals may fail to breed outside their natural habitat

space is limited ex situ

low genetic diversity

animals may not survive re introduction

animals may not be accepted by a herd when back in the wild

advantages of in situ

species and habitat conserved

less disruptive than ex situ

chance of recovery of species is higher

larger populations can be protected at once

disadvantage of in situ

cant control danger factors like disease or predators

advantages of ex situ conservation

can protect individuals

predation is easily managed

can check health of animals

competition of resources is reduced

breeding can be manipulated

disadvantages of ex situ

only small numbers are protected at a time

expensive

animals become close to humans, may catch disease or approach hunters

not all can breed successfully

what is CBD and its aims

the rio convention on biological diversity

signed by 150 governments;

conserve biodiversity

sustainable use of it components

sharing access of genetic resources

sharing research

setting up ex situ

sharing benefits arising from genetic resources

what is CITES and its aims

Convention of international trade in endangered species

ensure trade of species doesnt threaten its survival

regulate trade of selected species

ensure international trade doesnt threaten species

ensure trade in wild plants is prohibited for commercial use

ensure trade in artificially propagated plants is allowed subject to permit

ensure trade of endangered species may be allowed subject to permit

what is CSS and what are its aims

The countryside stewardship scheme

local conservation developed where farmers must agree to improve and conserve wildlife. the government offer to pay land owners for 10 years if they abide by the rules

dont cut hedgerows

leave grassy margins for wildflowers

increase educational access

flood risk management