Module 4 - Biodiversity

What is biodiversity?

refers to variety of organisms in an area
measure of all different plants,animals and other microorganisms species worldwide,the genes they contain and the ecosystems of which they form a part

What are the three levels of biodiversity?

habitat biodiversity - range of habitats in which different species live eg sand dunes and woodlands where each habitat occupied by a range of species
species biodiversity - number of species and number of individuals in each species
genetic diversity - variation in alleles within a population of a species so variation between individuals in same species which ensures we all do not look identical

What are the benefits of high genetic biodiversity and why?

having more than two alleles at a locus increases genetic diversity where having two different versions of the gene allows for better adaptation to a changing environment and resistance to disease

What are species and habitat?

species - a group of organims that can interbreed to produce fertile offspring so can breed to give rise to more offspring and consists of individual organisms that are similar in appearance,anatomy,physiology,biochemistry and genetics
habitat - place where a species lives within an ecosytem

What are the two measures of biodiversity?

species richness and species evenness

What is species richness?

total number of different species in a habitat - it is quantified by taking random samples and counting the species present - a higher species richness indicates greater diversity

What is species evenness?

comparison of relative number or abudance of individuals of each species in a community - measured by taking samples and counting individuals of each species - more even abundance mean higher species evenness and diversity where habitats where even numbers of individuals in each species likely to be more diverse than one in which individuals of one species outnumber all others - can be measured abundance in plants as percentage cover rather than number of individuals
carry out quantitative survey then take samples + record percentage cover of each plant species or large plants count number of individuals per unit area

How to assess genetic biodiversity?

assessed by calculating percentage of gene variants (alleles which are different versions of a gene) in a genome within isolated populations where a high genetic biodiversity means large variety of alleles in populations gene pool which increases a populations ability to adapt to environmental changes and so helps them avoid extinction
can be estimated by calculating number of loci in one individual that are heterozygous however does not give good measure of value of population as genetic resource

What are the two type of genes?

polymorphic gene is when a gene locus has multiple alleles where locus is the position of that gene on a chromosome
monomorphic gene is one where a single allele exists keeping the basic structure of individual in a species consistent

How to calculate proportion of polymorphic gene loci?

proportion measures diversity where a higher proportion of polymorphic gene loci means there is a greater genetic diversity
proportion of polymorphic gene loci = number of polymorphic loci / total number of loci

How can genetic biodiversity of a population be increased?

gene flow - interbreeding between different populations introducing new alleles
mutations in DNA - creates new alleles

How can genetic biodiversity of a population be decreased (7)?

1.selective breeding - humans choose organisms with advantageous characteristics to breed
2.captive breeding programmes - small group of individuals are bred in captivity
3.artificial cloning - using asexual reproduction to artificially produce large number of a particular
4.natural selection - species evolve and advantageous characteristics increase in a population
5.genetic bottlenecks - sudden decrease in population sixe means only a few individuals remain
6.founder effect - a few individuals form a new population split from original one
7.genetic drift - alleles randomly passed through generations and some may disappear by chance

How do you measure genetic diversity?

isolated populations such as captive animals in a zoo,rare breeds or pedigree animals may be small therefore genetic diversity may be limited where assessing their genetic diversity can help to assess value of that population as a resource for conservation where simple assessment can be made by looking at observable features of individuals if particular feature shows variation then suggests genetic diversity which is found if more than one allele for a particular gene locus which will lead to variation between individuals that leads to variations that are easily observable and more importantly means there will be more genetic differences between gametes produced by members of the population

Why do you use sampling to measure biodiversity?

very difficult to count all organisms in a habitat where some microorganism can be cultured on a nutrient medium in lab to gain estimate of numbers instead can sample a habitat by choosing a small portion and study that carefully then multiply up for whole habitat to estimate where important samples taken are representative

What is random sampling?

important to avoid bias and ensure samples are representative of whole population works by:
choose an area - randomly generate numbers as coordinates across area and using a portable global-positioning satellite which prevents sampling bias by removing human involvement in choosing samples - collect samples from random coordinates which gives us samples that are representative of population - repeat this several times which gives us a large sample size and minimises the effects of chance - analyse the data collected which lets us identify any relationships - cons include may not cover all areas of a habitat equally + species with low presence may be missed leading to underestimate of biodiversity

What are some techniques for sampling animals?

pooter - sample small insects by sucking air containing insects into a plastic container via a tube
sweep net - samples insects in long grass or air where net is swept in a ‘figure of eight’ motion and any insects will be caught in the net and then emptied on a white sheet to identify them but must be careful so don’t fly away and collected using a pooter before they fly away where this is suitable for low vegetation and not too woody and can be used in water
pitfall trap - samples small,ground-crawling animals like insects and spiders by catching them in a hidden trap in the soil which consists of container buried in soil so the rim is just below surface so any animal moving through leaf litter on soil surface will fall into the container where trap should contain a little water to stop animal crawling out again + in rainy conditions should be sheltered from rain
tree beating - samples invertebrates living in a tree or bush by shaking or beating the tree to dislodge insects onto a white sheet below and again need to be quick to identify and count animals before they fly away
kick sampling - samples river organims by kicking a river bank and catching organisms downstream in a net
tullgren funnel - devicd for collecting small animals from leaf litter where you place leaf litter in a funnel and a light above litter drives the animals downwards as litter dries out and warms up - fall through mesh screen to be collected in jar underneath the funnel - light trap can be used to collect flying insects at night which has UV light that attracts the insects and under light vessel contains alcohol where moths and other insects attracted to light eventually fall into alcohol

What are the two types of quadrats used for non-motile animals and plants?

frame quadrat - square frame divided into a grid where type and number of species within each section of quadrat is recorded - in random sampling use generated random numbers as coordinates to place quadrats within the habitat where tape measure will help with accuracy
point quadrat - frame with a horizontal bar through which pins are pushed at set intervals to touch the ground where each species the pin touches is recorded - one needle may touch several plants so possible to find above 300% cover should also record bare ground - best to use point frame at regular intervaks across quadrat (systematic sampling with randomly placed quadrat)

What are the methods to estimate number of individuals in a frame quadrat?

species frequency per quadrat calculated by number of squares in quadrat a species is found in / total squares in quadrat x 100
percentage cover per quadrat - an estimate of area within a quadrat that a species covers

What is the difference between random and non-random sampling?

non-random sampling involves selection based on specific criteria or patterns and sample is not chosen at random
random sampling removes human bias in sample selection improving reliability
non-random sampling does not use random selection so is prone to bias

What are the three main types of non-random sampling?

opportunisitic - uses conveniently available organisms and may not be representative of the population - may make decisions based on prior knowledge or during process of collecting data where research may deliberately sample an area knows contains particular species which is easier and quicker than random but data may be bias as presence of colourful species may entice researcher leading to overestimations and inaccurate estimate of biodiversity
stratified - divides population into subgroups based on characteristics and then random sample is taken from each stratum where number of samples taken in each stratum is proportional to size of stratum ensures all different areas of a habitat are sampled and species are not underrepresented due to fact that random sampling may miss certain areas
systematic - samples different areas in a habitat separatley at regular intervals to avoid bias these are at fixed intervals and method useful when the habitat shows a clear gradient in some environmental factor such as getting drier further from a pond however only species on line or within the belt can be recorded so other species may be missed leading to an underestimate of biodiversity

What is transect sampling?

method of studying distribution of organims in specific area it is typically used in systematic sampling
mark a line (transect) and take samples along this line at regular intervals which let us study how species distributions change across different areas within a habitat like from a woodland ro a lake

What are the two main types of transect sampling?

line transect - samples are taken at regular intervals along a line between two points
belt transect - samples are taken in an area along a line or between two parallel lines by using quadrats placed either side by side and moved along the line (continuous) which will provide quantitative data in band or belt across habitat or at regular intervals (interrupted) which will provide quantitative data at intervals across habitat

How do you sample plants in a habitat?

preparation - suitable clothing - apparatus needed to carry out sample - clipboard and pen - appropriate keys to identify plants - camera to record specimens
important you recognise all species correctly by using a dicot key and if unable to identify on site then take a photo and identify later - it may be necessary to visit site several times to get full estimate
at the site - best to use range of techniques as random sampling is important but may be helpful to modify sampling technique if habitats is not even which would be classed as opportunistic sampling (as make decisions during sampling process) and stratified sampling (as treating each part of habitat differently) + any sampling should cause as little disturbance as possible

How else can sampled plants be recorded?

large plants suchs as trees can be identified and counted individually however many plants may be too small or numerous so may be best to calculate value of percentage ground cover occupied by each species
using quadrats you can identify plants found and calculate percentage cover as a measure of their abundance + may be possible to estimate percentage cover of each species as some quadrats have a grid of string that divides quadrat into number of smaller squares usually 100 which helps make estimate more accurate

How can you sample animals by observation and trapping?

many animals are not easy to spot or larger anumaks detect presence so hide away but by careful observations can note the presence of many larger such as looking for footprints or identify droppings where ecologists often rely on these signs to estimate populations sizes + recent advances allows DNA sequencing to distinguish droppings providing more accurate way to calculate population size
small animals can be trapped and population estimates calculated where may need a licence can be trapped by a Longworth trap which must be monitored regularly to release trapped animals and this allows population size to be calculated using mark-release-recapture technique

What is mark release and recapture?

first capture a sample of animals - mark each individual in way that causes no harm number captured will be C1 - release marked animals and leave traps for another period of time - number captured on second occasion will be C2 and the number of already marked animals captured on second occasion is C3 - then calculate total population using formula total population= (C1 x C2)/C3
estimate can be affected by animals that learn trap is harmless and contains food or by animals who do not like experience therfore keep away from traps after first capture for larger mammals can be tagged instead of marked
death or migration may have occured between samples

What index can you use to work out biodiversity?

Simpson’s index of diversity calculates biodiversity using number of species and their relative abudance so takes both species richness and eveness into account
it involves 1 minus the sum of (n/N) squared of each species where n is individuals of particular species or percentage cover for plants and N total number of all individuals of all species or total percentage cover for plants

How can Simpson’s index be interpreted?

high value of indes indicates a diverse habitat which provides a place for many different species and many organims to live and a small change to environment may affect one species and if species is only a small part of habitat total individuals affected is small proportion of total number therefore effect on whole habitat is small so habitat tends to be stable and able to withstand change
low value for diversity suggests a habitat dominated by a few species and small change to environment affects one of those species could damage or destroy whole habitat such a small change could be disease or predator

How do you measure density of animals in a habitat?

calculating how many animals of each species there are per unit area of habitat where larger animals can be counted by observation and smaller ones by using sampling techniques this could be mark-and-recapture however if numerous small animals in soil can use net to sample whilst sifting through

What are some impacts of growing human population on biodiversity?

deforestation for development destroys habitats and reduces ecosystem diversity leaving fragment habitats
overuse of resources causes certain species to decline or go extinct reducing genetic and species diversity
urban sprawl isolates wildlife populations limiting breeding and decreasing genetic diversity
pollution kills species directly and harms habitats long term
all of the above cause number of species and genetic to decline as a result of human activities

What agricultural practises reduce biodiversity?`

farming methods aimed at maximising crop yields such as creating monocultures often decrease biodiversity as these practises decrease habitat,plant and animal diversity
populations decline as species lose food,shelter and breeding sites as reduce size of habitats and populations of species living there which reduces genetic diversity as it reduces as species has less capacity to adapt to changing conditions + may leave isolated and fragmented populations that are too small to survive

What are some agricultural practices that reduce biodiversity?

monocultures - involves growing single crops over large areas typically without crop rotation directly decreasing diversity of plants and of species that depend on them for food or habitat + also depletes nutrients from soil - eg palm oil in Indonesia + Malaysia
converting woodland + hedgerows into fields - decreases number of trees and other species and destroys habitats relied on by many species
filling in ponds,draining marshes + over grazing of land - directly destroys habitats and reduces species diversity
removing weeds with herbicides + using pesticides to kill crop pests - may harm other species or those dependent on target species
using inorganic fertilisers - may runoff into water courses causing issues for aquatic species
selective breeding - reduces genetic diversity as farmers select particular traits where certain characteristics are ignored + selecting specific breeds means others become rare reducing genetic diversity as varieties have been lost

How can you balance conservation and agriculture?

maintaining hedgerows - reducing pesticides and herbicide use - using organic fertilisers - using crop rotation

What are the impacts of climate change on biodiversity?

cc is significant long-lasting changes in weather patterns
burning fossil fuels releases greenhouse gases causing global warming - climate change alters regional climates around world which causes shift in biodiversity in various habitats this activity means species lose their genetic diversity with less variation between individuals where as cilimate changes less able to adapt to changes in temperature and rainfall where only alternative will be to move and follow climate patterns to which they are most suited meaning slow migration occurs where may be obstructed by major human developments,large bodies of water + mountain ranges

What are the effects of climate change on biodiversity?

regions experience changes in temperatures and rainfall and most species are adapted to specific climates
changed conditions will make certain areas more or less habitable in general
suitable habitats for some species will expand or contract eg melting ice caps remove a habitat for all polar animals
changing climate conditions may influence species distribution and migration
slow-moving species may become extinct if change is too rapid or severe
if conditions in general become watmer tropical diseases will be more likley to spread
rising sea levels may lead to more frequent flooding of terrestrial habitats

How does climate change affect protected areas?

as climate changes selected site no longer maintains conditions the conditions the protected animals need so animals so will migrate out of protected area where domesticated organisms at risk as are selectively bred for best yield meaning little variation as a result unlikely to adapt changing conditions and vulnerable to disease so agriculture effieciency will decline + less food will be available so farmers need to change crops they grow so crops from S Europe may be grown in Britain

What are ecological reasons for conserving biodiversity?

maintaing biodiversity is vital for healthy functioning ecosystems due to complex interdependence within them
food webs rely on multiple species so declines in certain species can disrupt food chains
losing keystone species that have disproportionately large effects on their environment relative to their abundance destabilises these ecosystems eg predators may limit population of herbivoures so vegetation not overgrazed eg mountain lions and could be plants eg sugar maple tree where the roots can transfer water to shallower regions that are dry making it available to other plants + beavers which build dams provide habitats
nutrients cycle depend on decomposers recycling matter like carbon,nitrogen,sulfur and phosphorous through ecosystems
provides resilience to a changing climate,other abiotic stresses and disease

What are economic reasons to maintain biodiversity?

diverse ecosytems can support industries by immediately providing useful products for protecting future profits
products include fuel production,raw material compounds,many medicines originate from living organisms + wildlife is source of income for countries through tourism
protecting genetic diversity supports future industries and economy by providing: gene sources for future medicines and products that have not yet been discovered + resilience against a changin climate,other abiotic stresses and disease to economically useful organisms

How does reduced biodiversity affect food production?

causes depletion of soil which means loss of soil fertility caused by removal of minerals by continuous cropping so when continuous monoculture soil becomes less fertile meaning agricultural yields decline as when crop harvested minerals removed and when monoculture grown always takes same nutrients

What are agricultural reasons to maintain biodiversity?

agriculture is important to economy and to general survival of human population as provides food
where monocultures that repeatedly grow single crops deplete soil nutrients which is bad for agriculture and therefore bad for economy as causes lower crop yields + reliance on expensive fertilisers
promoting diverse ecosystems in agricultural settings and preventing use of monoculture can therefore be economically beneficial
wild relatives of cultivated crops provide genetic resources to widen the genetic resources to widen genetic diversity of cultivated crops allowing new varieties of crops with desired traits to be bred
genetic diversity provides a safeguard against diseases or pests
many crops rely on insect pollinators to reproduce

What are aesthetic reasons for conserving biodiversity?

benefits include:
enriching our environment and providing inspiration for musicians,artists + poets
helping people recover from stress and injury with feelings of joy and wellbeing when observing variation within nature

What are genetic reasons for conserving biodiversity?

genetic resources by allowing biodiversity to decline means genetic diversity also decreases which may mean we lose useful alleles like disease-resistance
number of potential new medisicines and vaccines to be found in plants is also unknown so if destroyed we lose potential

What is extinction?