biodiversity Flashcards

Question

method for choosing sample sites

Answer 1

Mark up a grid on a map or a to-scale drawing of the area being studied and label the grid with coordinates It is important that the area is big enough to get a representative estimate for the specific habitat/ecosystem Use a random number generator to choose a set of coordinates This is done to avoid sampling bias which could lead to over or under-estimation (either subconsciously choosing areas that are easier to access or that look like they contain individuals)

Answer 2

The contents within quadrats can be counted using different measurements Population density, percentage cover and species frequency are all different ways of counting and recording the number of different species and individuals present within a quadrat

Answer 3

Place a quadrat at the generated coordinate Count the number of individuals in each quadrat Use a running mean to determine the number of quadrats required to get a representative sample: Calculate the mean number of individuals per quadrat for the first two quadrats found, then the mean of the first three, then the mean of the first four and repeat until there is no further significant change in the mean

Answer 4

To calculate the estimated population size for the whole area or habitat, divide the whole area by the area of one quadrant, then multiply this value by the mean number of individuals per quadrat

Answer 5

Usually used for plants Place a grid quadrat (a square frame split into 100 smaller squares) at this coordinate Each square of a grid quadrat is equivalent to 1% cover Count the number of squares in each quadrat within which the species occupies over half the square If 30 squares contain the species, the percentage cover is 30% This method is subjective and therefore the same person should make the estimate for all samples to control this variable

Answer 6

Place a frame quadrat at multiple coordinates generated Count the number of quadrats that contain the species If 3 out of 10 quadrats contain the species the frequency is 30%

Answer 7

Species density indicates how many individuals of that species there are per unit area The number of individuals counted across all quadrats is divided by the total area of all the quadrats For example, if 107 bluebells were found across 50 quadrats that are 1m2 each the species density would be 107/50 = 2.14 individuals per m2

Answer 8

It can sometimes be difficult to count individual plants or organisms. When this is the case percentage cover of the species within the quadrat can be estimated instead The quadrat is divided into 100 smaller squares. The number of squares the species is found in is equivalent to its percentage cover in that quadrat For example, if grass is found in 89 out of 100 squares in the quadrat then it has a percentage cover of 89%

Answer 9

Species frequency is the probability that the species will be found within any quadrat in the sample area The number of quadrats that the species was present in is divided by the total number of quadrats and then multiplied by 100 For example, if bluebells were found in 18 out of 50 quadrats the species frequency would be (18/50) x 100 = 36%

Answer 10

Quadrats and transects can only be used for sessile and immobile species (eg. plants and slow-moving animals) Some species can be counted to find their abundance but others that are very small or in high numbers require abundance to be calculated using percentage cover or frequency techniques The frequency technique shows how common a species is but it does not give information on the estimated number of individuals or the size of the population

Answer 11

Percentage cover and frequency, when used together, give a good picture of the distribution of a species If a species had a high mean percentage cover but a low frequency it would suggest the species lives in groups in preferred areas of the habitat This can be used to answer questions such as: does the species prefer light or dark and wet or dry areas etc.

Answer 12

other sampling techniques are useful for non-motile (sessile) organisms Different methods are required for estimating the number of individuals in a population of motile animals The mark-release-capture method is used

Answer 13

The first large sample is taken. As many individuals as possible are caught, counted and marked in a way that won’t affect their survival e.g. if studying a species of beetle, a small amount of brightly coloured non-toxic paint can be applied to their carapace (shell) The marked individuals are returned to their habitat and allowed to randomly mix with the rest of the population When a sufficient amount of time has passed another large sample is captured The number of marked and unmarked individuals within the sample are counted The proportion of marked to unmarked individuals is used to calculate an estimate of the population size

Answer 14

The formula for the calculation is: N = (n1 × n2) ÷ m2 Where: N = population estimate n1 = number of marked individuals released n2 = number of individuals in the second sample (marked and unmarked) m2 = number of marked individuals in the second sample

Answer 15

When using the mark-release-capture method, there are a few assumptions that have to be made: The marked individuals are given sufficient time to disperse and mix back in fully with the main population The marking doesn't affect the survival rates of the marked individuals (e.g. doesn't make them more visible and therefore more likely to be predated) The marking remains visible throughout the sampling and doesn't rub off The population stays the same size during the study period (i.e. there are no significant changes in population size due to births, deaths or migrations into or out of the main population)

Answer 16

Once the abundance of different species in an area has been recorded the results can be used to calculate the species diversity or biodiversity for that area Species diversity looks at the number of different species in an area (species richness) but also the evenness of abundance across the different species in that area (species evenness) Simpson’s index of diversity (D) can be used to quantify the biodiversity of an area

Answer 17

The formula is: D= 1 - (sum of (n/N)^2) Where: n = total no. of organisms for a single species N = total no. of organisms for all species D= diversity

Answer 18

Step 1: First calculate n / N for each species Step 2: Square each of these values Step 3: Add them together and subtract the total from 1

Answer 19

The value of D can fall between 0 and 1 Values near 1 indicate high levels of biodiversity Values near 0 indicate low levels of biodiversity

Answer 20

The genetic diversity within a species is the genetic variation that exists within a species Although individuals of the same species will have the same genes at the same loci they will not necessarily have the same alleles for each gene

Answer 21

The gene pool is comprised of all the alleles of all the genes within a species There can be genetic differences or diversity between populations of the same species which increases the size of the gene pool This may be because the two populations occupy slightly different ranges in their habitat and so are subject to slightly different selection pressures that affect the allele frequencies in their populations

Answer 22

Genetic diversity within a single population can also be observed Diversity in a species is important as it creates a larger gene pool which can help the population adapt, and survive changes in the environment The changes could be biotic factors such as new predators, pathogens and competition with other species or they could be abiotic factors like temperature, humidity and rainfall

Answer 23

The proportion of polymorphic gene loci The number of loci that have two or more alleles The proportion of the population that is heterozygous for any specific gene locus Allele richness The number of different alleles that exist for specific genes All three measurements involve determining whether there are multiple alleles at a locus. Phenotypes can sometimes be used to identify the presence of multiple alleles For some genes, when each different allele is expressed in the phenotype of an individual they produce observable differences For other genes, different alleles do not always produce an observable change in the phenotype of individuals In this situation, the DNA sequences or the protein products of the alleles must be examined and compared -Note that some of the differences discovered might not be of major importance

Answer 24

Genetic polymorphism occurs when there are two or more alleles present at a single loci The rarest allele will have a frequency greater than 1% or greater than 5% These numbers are of no particular significance, they have been randomly chosen by scientists

Answer 25

A monomorphic locus is one that does not have multiple alleles Sometimes tables of data will refer to monomorphic loci as having one allele

Answer 26

A polymorphic locus is one that has multiple alleles The most common allele must have a frequency less than 95% or 99% If the most common allele has a frequency greater than 99% then the other allele(s) are extremely rare and likely to disappear

Answer 27

scientists must identify a number of gene loci to investigate They identify how many of these gene loci are polymorphic The number of polymorphic gene loci is then divided by the total number of loci being investigated The equation for calculating the proportion of polymorphic gene loci (P) is: P = number of polymorphic gene loci ÷ total number of loci investigated

Answer 28

This is a useful method when investigating allozymes Allozymes or alloenzymes are slightly different forms of the same enzyme. Each allozyme is coded for by a different allele and they function in a slightly different manner

Answer 29

Due to the fact that the genetic code is degenerate, the amino acid sequence of two alleles could be the same but their DNA base sequence could be different Nearly all of the genetic diversity assessment is now done at the level of base sequences Scientists usually focus on specific sequences in nuclear DNA and mitochondrial DNA (mtDNA)

Answer 30

The global human population has been growing exponentially for the last 150 years There are many reasons for this exponential growth, including: Improved technology leading to an abundance of food = increase in birth rate Improved medicine, hygiene and health care = decrease in death rate

Answer 31

Humans use many resources from the Earth such as land (for settlements and agriculture), water, wood and fossil fuels As the human population increases and countries become more economically developed, our requirement for these natural resources also increases This is having a harmful effect on many aspects of the environment, including aquatic and terrestrial ecosystems, and our atmosphere and climate The damage to these ecosystems is negatively impacting the species and habitats contained within them This means that a conflict exists between human needs and the conservation of biodiversity

Answer 32

Many human needs lead to natural environments being destroyed When land is cleared for agriculture, industry, energy production housing, transport, leisure facilities, waste disposal and water storage, this results in: Habitat loss (plant and animals completely lose their habitats) Habitat fragmentation (habitats are divided into small areas - populations living within these separated habitat fragments are more likely to suffer from inbreeding or local extinction) Deforestation is one of the most damaging forms of habitat destruction, as forest habitats often have the highest levels of biodiversity Marine habitats are also being destroyed, including: Coral reefs (some people use dynamite as an extreme way to catch fish, which damages corals) Sea beds (fishing practices such as trawling, where nets are dragged along the sea bed, destroy this important habitat)

Answer 33

Many of the natural resources exploited by humans are actually being overexploited (they are being used up faster than they can be replaced) For example, much deforestation is unsustainable as trees are removed but are not replaced by replanting. Even if they are replanted, the rate at which trees are being removed far exceeds the rate at which they are growing back Fish stocks are also being overexploited, which is also having a knock-on effect on organisms that feed on these fish species, such as marine mammals and seabirds

Answer 34

Hunting is another form of overexploitation, as many wild, non-farmed species of animals are being hunted and removed more quickly than their wild populations can be replenished An example is the hunting of animals for 'bush meat' in developing countries (including the hunting of primates such as monkeys and chimpanzees, as well as other mammal and reptile species)

Answer 35

After the second world war, there was a massive change in how food was produced There was a need to produce more food, at a quicker rate It was then that modern farming practices began: Farms became more specialised so they grew only one crop or raised one type of livestock (monoculture) There was a switch to growing cereal crops rather than vegetables Fields were made bigger to accommodate machinery via the removal of hedgerows and stonewalls More land was made suitable by draining wetland and filling in ponds The use of fertilisers and pesticides massively increased

Answer 36

Monocultures support much lower levels of biodiversity compared to natural habitats or even natural grazing land (that has a large variety of plant species present which can support a much greater range and number of insect species and bird species) Hedgerows represent an important habitat for many insects, small mammals and birds, which can nest there. As hedgerows are being increasingly removed, this habitat and the biodiversity it supports is lost Fertilisers can leach into waterways, causing eutrophication, which can lead to the death of many aquatic invertebrate and fish species Pesticides (e.g. insecticides) used on crops kill insect pests but also kill many non-target species, including important insect pollinators like bees

Answer 37

Bumblebees are essential pollinators that pollinate wildflowers and valued crops such as oilseed rape and peas Almost a quarter of the European bumblebee species are threatened with extinction There has been a very rapid decline in bumblebee numbers in recent years Bumblebees require habitats with a large number of flowering plants to ensure a supply of pollen and nectar all year round. Examples of this are hedgerows, field margins and grasslands It has been suggested that the extensive farming of crops and the use of pesticides are contributing to this decline The monoculture of crops reduces plant diversity for bumblebee habitats Although they are not the target species, pesticides can have a negative effect on bumblebees

Answer 38

A high yield and profit are two factors that make farming economically viable Farming practices that maintain or increase biodiversity can be expensive, labour intensive, time-intensive. They can also reduce the yield of crops and livestock For example, if a farmer stops using pesticides on crops, the number of bumblebees will increase but the number of pest species that destroy crops will also increase which will reduce crop yield and profit This means that the farmer will have to charge more for his produce, in what is a very competitive market It is difficult to find the balance between conservation and farming due to these knock-on effects

Answer 39

Human-caused climate change is causing weather patterns to change and the frequency of extreme weather events, such as hurricanes, typhoons, floods and droughts, to increase It is feared that climate change is now occurring too fast for many species to be able to adapt to these changes, which could result in many species becoming extinct and a major decline in biodiversity

Answer 40

Global warming (a result of climate change) is causing many species to move towards the poles or to higher altitudes However, these species may not be able to compete with, or may even out-compete, the species already present in these habitats, with either result leading to decreased biodiversity Some species (such as plant species) may not be able to move or change their distributions fast enough to adapt to increasing temperature and may go extinct as a result

Answer 41

Global warming (and the human-generated CO₂ that is the primary cause of this) is also threatening marine biodiversity: Increasing atmospheric CO₂ is leading to more CO₂ dissolving in seawater, decreasing its pH (known as ocean acidification). This is negatively affecting organisms that require calcium carbonate for shells (e.g. plankton and coral polyps) Increased ocean temperatures have also led to an increased frequency of coral-bleaching events, where the tiny organisms that live inside corals and help keep them alive leave due to temperature stress. Without these organisms, the corals die and are broken down, eventually leading to the loss of whole coral reefs and as a result, the loss of the huge amount of biodiversity that depends on them

Answer 42

Biodiversity is the range and variety of genes, species and habitats within a particular region It is made up of three components: Genetic diversity Species diversity Ecosystem diversity Global biodiversity has a major impact on humans and all other species on the planet There are many reasons for maintaining biodiversity: Ecological Economic Aesthetic Social Moral/ethical Environmental Agricultural

Answer 43

Biodiversity has a major effect on the stability of an ecosystem A more diverse ecosystem is better able to survive and adapt to environmental changes or threats For example, if the temperature of a species-rich lake rises due to global warming: Some species of fish in the ecosystem are unable to cope with the change while others can The fish that are able to cope will survive, reproduce and keep contributing to the ecosystem Within communities there are keystone species that have a larger impact on the ecosystem than others When these species are lost there are several knock-on effects Bush elephants in the African savannah are a keystone species They graze in a very extreme way, knocking over and eating several species of tree This destruction of vegetation actually helps to maintain the ecosystem Elephant dung also provides a habitat for many important fungi and insect species When elephants were legally hunted for their ivory, their numbers reduced and scientists observed a major negative impact on the savannah

Answer 44

Ecosystems have a lot of economic value Many of the medicines used today have originated from plants, fungi and bacteria -For example the cancer-fighting drug paclitaxel is sourced from Pacific and Himalayan Yew Trees The Himalayan Yew has declined in numbers due to over-harvesting for fuel and medicine Due to the large number of drugs that have already been sourced from nature it is reasonable to assume that there are other drugs, yet to be found in nature, that could be used in the future Ecotourism a major source of income for many countries Many tourists travel to and spend money in National parks so they can see wildlife Increased tourism in a country contributes to the economy and provides jobs Ecosystems have also made major contributions to the field of science and technology The specific enzyme used in DNA sequencing was first discovered in thermophilic bacterium found in a hot spring in Yellowstone National Park, USA

Answer 45

Humans find great joy and pleasure in the beauty of nature It provides inspiration for creatives such as photographers, poets, musicians and artists There is a strong argument for preserving biodiversity because of its aesthetic benefits

Answer 46

Many people enjoy spending time in the natural environment There are many activities that people can do together in nature, e.g. birdwatching, walking, climbing Such environments may be lost if they are not conserved, with the loss of the social benefits that they can bring

Answer 47

Many people believe that humans have a moral obligation to prevent the loss of biodiversity that results from human activities Humans share the planet with millions of others species and they have no right to cause the extinction of other species As humans are the most intelligent species on the planet the responsibility falls upon their shoulders to protect and value all of the organisms on the planet

Answer 48

Humans need diverse ecosystems because of the essential environmental services they provide Plants absorb carbon dioxide from the atmosphere and help to reduce the greenhouse effect and climate change Microorganisms digest and break down the masses of organic waste that are produced by larger organisms Humans have irrigation and drinking water thanks to the transpiration of plants and their contribution to the water cycle Different fungi and bacteria species are a major part of the nutrient cycle that allows for nutrients to reenter the soil for further plant growth Plants are producers in food webs. They are both a direct and indirect energy source for humans through fruit, vegetables and meat

Answer 49

Most of the crops that humans grow are very uniform with low genetic diversity The wild relatives of crops can provide a source of genetic diversity to rescue crops that are affected by disease or other disasters Many of the wild relative species are under threat due to habitat destruction and climate change All of the world's potato crop comes from a single species This lack of species diversity makes the crop highly susceptible to disease -There are over 100 species of wild potatoes that grow in the Andes -These Andean species act as a source of alleles for disease resistance -These alleles have been introduced to the potato crop through gene technology and interbreeding

Answer 50

Ideally a species should be kept in their natural habitat as all the support systems they need to maintain life already exist there; conservation carried out in the natural habitat is known as in situ conservation National parks and marine parks are examples of conservation methods that do this

Answer 51

When it is not possible to do this endangered species can be captured and placed in captivity for conservation efforts; conservation outside the natural habitat is known as ex situ conservation Zoos and botanic gardens take part in conservation programmes Scientists have also come up with several methods to try and ensure the long-term survival of endangered species through frozen zoos and seed banks

Answer 52

National parks are areas within countries where the wildlife and environment are protected Governments control these areas and pass legislation to ensure their protection There are several restrictions -Humans access is strictly controlled -Industrial activities such as agriculture and building are tightly regulated -Hunting is limited or completely prohibited

Answer 53

Marine parks are protected areas of water that have been set up for the conservation of endangered marine ecosystems and species They also have restrictions to prevent overfishing and pollution

Answer 54

Public engagement with conservation efforts is important for long term success: National and Marine parks can attract thousands of tourists each year which increases money and awareness for the conservation effort Involving members of the local community in the management of protected areas can provide jobs and increase acceptance of the parks Some of the profits made from parks can be used to improve the health and education standards in the nearby communities to illustrate the benefits of having such areas nearby

Answer 55

A large proportion of the land and water surrounding the Galapagos Islands is protected. Humans are not allowed to travel to many of the islands in the National park and fishing is illegal in the Marine park areas. Management of these areas is shared between locals and conservation experts. Since it was established over 50 years ago, there have been strong efforts made to remove invasive species and increase native species. Rats and goats are captured and removed and the alien plant species elephant grass is dug up and destroyed while giant tortoises are being reintroduced.

Answer 56

Zoos can also contribute towards the conservation of endangered animal species Captive breeding programmes can breed individuals of a species so their offspring can be released into the wild Zoos are an invaluable resource for scientific research Scientists are able to closely study animal’s genetics, behaviours and habitat needs There are some problems with zoos and their role in conservation: Captive breeding of small species populations can reduce genetic diversity Certain animal species will not breed in captivity Not all zoos can provide adequate habitats for animals with specific needs There are stories of both success and failure when it comes to zoos and conservation: -The oryx is an antelope-like species that was saved from extinction and reintroduced into the wild in Africa thanks to zoos and captive breeding programmes -Pandas have been in captive breeding programs for over 60 years and not a single panda has been reintroduced into the wild

Answer 57

Botanic gardens are the plant equivalent of zoos They use cuttings and seeds collected from the wild to establish a population of the endangered species in captivity Methods of tissue culturing and cloning can also be used to obtain large numbers of plants from a small sample size The captive population can be used in the future for reintroduction into habitats where they have become rare Research is a major role of botanic gardens They investigate reproduction and growth in different plant species so that they can be grown in captivity If the plants original habitat no longer exists they try to find suitable new habitats Both zoos and botanic gardens are instrumental to education They help to raise awareness of vulnerable, endangered species and conservation efforts worldwide

Answer 58

Frozen zoos store genetic material from animals (eggs, sperm, tissue samples etc) at very low temperatures so that they can be kept for a very long time Ideally samples are collected from different individuals of the same species to maintain the gene pool The temperature used is roughly -196oC A large amount of genetic material can be stored in a relatively small space In the future genetic materials from extinct animal species could be used to breed and reintroduce a species through IVF and genetic engineering The San Diego Zoo in the USA has frozen zoo facilities

Answer 59

A seed bank is a facility that conserves plant diversity by drying and storing seeds in a temperature controlled environment Usually, seeds of the same species are collected from different sites to maintain the gene pool If the plant species goes extinct then the seeds can be used to grow them again Seeds can only be stored for so long. After a certain period of time the stored seeds are grown into plants and fresh seeds for storage are taken from those plants The Svalbard Global Seed Vault in Norway has almost 1 million species of plant seed. It is located in the Arctic Circle with ideal environmental conditions Many organisations send seeds from crop plants to be stored there for safekeeping Some plants have seeds that can not be frozen such as coffee and cocoa plants In order to preserve the genetic diversity of these plants successive generations must be grown or tissue cultures taken

Answer 60

International cooperation is essential if conservation is to be successful There are several agreements and authorities that exist within and between countries with the aim of protecting and conserving species worldwide

Answer 61

The International Union for the Conservation of Nature (IUCN) is described as “the global authority on the status of the natural world and the measures needed to safeguard it” One of the duties that the IUCN carries out is assessing the conservation status of animal and plant species around the world The IUCN has their own classification system There are several different categories and levels that a species can fall into depending on their population numbers and the threats and risks to those populations Scientists use data and modelling to estimate which category each species should be in Animals that are on the IUCN Red List of Threatened Species™ can be seen online as this list is made public

Answer 62

The Convention on Biological Diversity (CBD) was signed at the Earth Summit in Rio de Janeiro in Brazil in 1992 The convention had three main goals: The conservation of biological diversity by use of a variety of different conservation methods The sustainable use of biological resources The fair and equitable sharing of benefits arising from genetic resources The countries that signed the convention agreed to design and implement national strategies for the conservation and sustainable use of biodiversity, as well as to organise international cooperation and further international meetings

Answer 63

The Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES) is a global agreement that has been signed by over 150 countries Its aim is to control the trade of endangered species and their associated products For example, elephants and their ivory tusks CITES categorizes endangered and vulnerable species into three appendices: Appendix I : species that are endangered and face the greatest risk of extinction (for example, the red panda) Appendix II: species that are not currently endangered or facing extinction, but will be unless trade is closely controlled (for example, the venus fly trap) Appendix III: species included at request of the country that is regulating trade of the species and trying to prevent its overexploitation (for example, the two-toed sloth in Costa Rica) There are different trading regulations that apply to each appendix: For species in appendix I: all trade in the species and their associated products is banned For species in appendix II: trade is only granted if an export permit has been issued by the involved countries For species in appendix III: permits are required for regulated trade. Permits are easier to come by for species in this appendix Scientists are continuously adding new species and reviewing the status of species already in the database There are several concerns about the efficacy of CITES listings When the trade of a certain endangered species becomes illegal, its price increases The increased economic value of the species can be a major incentive for people to break the law

Answer 64

The Countryside Stewardship Scheme (CSS) was a scheme dating back to the 1980s that provided funding (i.e. a financial incentive) to farmers and private landowners in England who used environmental management strategies to protect and increase the natural biodiversity on their land This scheme was replaced by the Environmental Stewardship Scheme (ESS) in 2005 In order to qualify for the scheme, farmers and private landowners have to: Provide and protect valuable wildlife habitats such as ponds, hedgerows and buffer zones surrounding farmed areas Ensure their land is managed well, maintaining its traditional character Protect any natural resources or historic features present on their land Conserve any traditional crops or livestock present on their land Provide visitor opportunities so people can learn about the countryside and how important it is in sustaining biodiversity