biodiversity

Question 1

biodiversity and how it is assessed

Answer 1

Biodiversity can be thought of as a study of all the variation that exists within and between all forms of life

Biodiversity looks at the range and variety of genes, species and habitats within a particular region

It can be assessed at three different levels:

-The number and range of different ecosystems and habitats

-The number of species and their relative abundance

-The genetic variation within each species

Biodiversity is very important for the resilience of ecosystems, in that it allows them to resist changes in the environment

Question 2

ecosystem or habitat diversity

Answer 2

This is the range of different ecosystems or habitats within a particular area or region

If there is a large number of different habitats within an area, that area is likely to have high biodiversity
-A good example of this is a coral reef. They are very complex with lots of microhabitats and niches to be exploited

If there are only one or two different habitats within an area, that area is likely to have low biodiversity
-Large sandy deserts typically have very low biodiversity as the conditions are basically the same throughout the whole area

Question 3

species richness

Answer 3

An ecosystem such as a tropical rainforest that has a very high number of different species would be described as being species-rich
-Species richness is the number of species within an ecosystem

Species richness is a measure of the number of different species within a given area

An area with a greater number of species will have a greater species richness

For example, a tropical rain forest has a very high number of different species so it would be described as being a species-rich area

However, species richness can be a misleading indicator of diversity as it does not take into account the number of individuals of each species

Question 4

species evenness

Answer 4

Species diversity includes the number of different species in an ecosystem, and also the evenness of abundance across the different species present (known as species evenness)

The greater the number of species in an ecosystem, and the more evenly distributed the number of individuals from each species, the greater the species diversity

For example, an ecosystem can have a large number of different species but some species may be very rare (may only have a few individuals) in that particular ecosystem.

As a result, the ecosystem does not necessarily have high species diversity

Question 5

stability in ecosystems

Answer 5

Ecosystems with high species diversity are usually more stable than those with lower species diversity as they are more resilient to environmental changes

For example in the Pine forests of Florida, the ecosystem is dominated by one or two tree species. If a pathogen comes along that targets one of the two dominant species of trees, then the whole population could be wiped out and the ecosystem it is a part of could collapse

Question 6

genetic diversity

Answer 6

The genetic diversity within a species is the diversity of alleles and genes in the genome of species

Although individuals of the same species will have the same genes they will not necessarily have the same alleles for each gene

Question 7

how is genetic diversity measured

Answer 7

Genetic diversity is measured by working out the proportion of genes that have more than one form (allele) and how many possible alleles each gene has

Question 8

genetic differences within the same species

Answer 8

There can be genetic differences or diversity between populations of the same species

These differences may arise 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

Question 9

genetic diversity within a single population

Answer 9

Genetic diversity can also be observed within a single population

Genetic diversity in a species is important as it can help the population adapt to, and survive, changes in the environment

The changes could be in biotic factors such as new predators, pathogens and competition with other species

Or the changes could be through abiotic factors like temperature, humidity and rainfall

Question 10

limitations of genetic diversity

Answer 10

Genetic diversity is limited in populations that are very small or isolated

Inbreeding in small, isolated populations leads to a high proportion of individuals being homozygous (e.g. AA to aa) for many genes, resulting in lower genetic diversity

This can mean that genetic diseases caused by recessive alleles can become more common in these populations

Question 11

sampling to determine biodiversity

Answer 11

Measuring the different levels of biodiversity within an ecosystem can be challenging

Finding out which species live in an ecosystem and the size of the populations requires the identification and cataloguing of all organisms present to build a species list

This is possible for areas that are very small or where the species are very large like trees

However, for larger and more complex ecosystems like rainforests, it is simply impossible to find, identify and count every organism that exists there

When this is the case, different samples of the area can be taken and used to make an estimate for the total species numbers in the area

Question 12

sampling

Answer 12

Sampling is a method of investigating the abundance and distribution of species and populations

There are two different types of sampling:
Random
Non-random

Question 13

random sampling

Answer 13

In random sampling, the positions of the sampling points are completely random or due to chance

This method is beneficial because it means there will be no bias by the person that is carrying out the sampling that may affect the results

When a sampling area is reasonably uniform or has no clear pattern to the way the species are distributed then random sampling is the best choice

Question 14

non random sampling

Answer 14

In non-random sampling the positions of the sampling points are chosen by the person carrying out the sampling

There is a possibility that the person choosing could show bias towards or against certain areas

Individuals may deliberately place the quadrats in areas with the least species as these will be easier and quicker to count

This is unrepresentative of the whole area

Question 15

what is random sampling used to estimate

Answer 15

Some ecosystems are very complex with large numbers of different species of different sizes

For the sake of logistics, random sampling is often used to estimate the distribution and abundance of species

The distribution of a species describes how it is spread throughout the ecosystem

The abundance of a species is the number of individuals of that species

Question 16

quadrants

Answer 16

When carrying out sampling, square frames called quadrats can be used to mark off the area being sampled

Quadrats are square frames made of wood or wire

They can be a variety of sizes eg. 0.25m2 or 1m2

They are placed on the ground and the organisms within them are recorded

They can be used to measure the distribution and abundance of plants or slow-moving animals

Quadrats of different sizes can be used depending on what is being measured and what is most suitable in the space the samples are being made in

Question 17

sampling bias with quadrants

Answer 17

Quadrats must be laid randomly in the area to avoid sampling bias

This random sampling can be done by converting the sampling area into a grid format and labelling each square on the grid with a number

Then a random number generator is used to pick the sample points

Once the quadrat has been laid on the chosen sample point the abundance or percentage cover of all the different species present can be recorded

Question 18

other techniques/ equipment that can be used

Answer 18

Sweeping nets: these are large, strong nets with a fine material (very small holes) that are used to catch flying insects and insects that live in long grass by sweeping the net back and forth through the grass

Pitfall traps: these are cans or jars that are buried in the ground that are used to catch ground-dwelling (often nocturnal) insects and other invertebrates as they fall into the trap

Pooters: these are small plastic or glass containers with two tubes sticking out that are used to suck up small insects and other small invertebrates. The first tube is placed over the insect and the second tube is used by the scientist to create suction

Tullgren funnel: these are funnels with a light bulb above and a container below that are used to collect invertebrates that live in leaf litter or soil. The leaf litter or soil is placed in the funnel and the light and heat forces the invertebrates to move down until they drop into the container

Kick-sampling: this technique is used to catch freshwater invertebrates living in streams or rivers. A net in placed on the stream-bed so that the water is flowing into it and the stream-bed just above the net is churned up by the scientist (using their foot) for a set period of time. The invertebrates are carried by the stream into the net

Question 19

non random sampling types

Answer 19

Random sampling is not always possible or may take an impractically long time. In these cases, non-random sampling may be more suitable

There are three main types of non-random sampling:
Opportunistic sampling
Stratified sampling
Systematic sampling

Question 20

opportunistic sampling

Answer 20

Opportunistic sampling involves picking and choosing sampling locations based on various non-random factors. For example, students on a field trip may be told they can only collect samples from locations that are nearby, easy to reach, and safe

Question 21

stratified sampling

Answer 21

Stratified sampling involves matching the number of sampling locations in a particular habitat with the relative proportion of area that habitat covers in the whole area being studied.

For example, if 10% of a dense woodland being sampled is actually made up of grassy clearings, then 90% of the sample locations should be in the woodland habitat and 10% in the grass habitat

Question 22

systematic sampling

Answer 22

Systematic sampling is used when there is a clear change in the physical conditions across the area being studied

For example, there may be changes in altitude, soil pH or light intensity

Methods using transects can help show how species distribution changes with the different physical conditions in the area

A transect is a line represented by a measuring tape, along which sample are taken

Question 23

line transect

Answer 23

For a line transect:
-Lay out a measuring tape in a straight line across the sample area
-At equal distances along the tape, record the identity of the organisms that touch the line. For example, every 2m
-This produces qualitative data

Question 24

belt transect

Answer 24

For a belt transect:
-Place quadrats at regular intervals along the tape and record the abundance or percentage cover of each species within each quadrat
-This produces quantitative data

Question 25

method for choosing sample sites

Answer 25

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)

Question 26

getting measurements from quadrants

Answer 26

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

Question 27

calculating population density

Answer 27

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

Question 28

calculating the estimated population size

Answer 28

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

Question 29

calculating the abundance of a species using percentage cover

Answer 29

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

Question 30

calculating the abundance of a species using frequency

Answer 30

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%

Question 31

species destiny

Answer 31

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

Question 32

percentage cover

Answer 32

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%

Question 33

precise frequency

Answer 33

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%

Question 34

limitations of using quadrats

Answer 34

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

Question 35

distribution of species

Answer 35

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.

Question 36

mark-release-capture method

Answer 36

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

Question 37

for a single species in the area

Answer 37

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

Question 38

formula for population size estimate

Answer 38

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

Question 39

assumptions from mark release capture

Answer 39

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)

Question 40

simpsons index

Answer 40

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

Question 41

simpson index formula

Answer 41

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

Question 42

calculating simpsons index

Answer 42

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

Question 43

D in simpsons index formula

Answer 43

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

Question 44

assessing genetic diversity

Answer 44

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

Question 45

gene pool

Answer 45

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

Question 46

genetic diversity in a single population

Answer 46

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

Question 47

Genetic diversity can be assessed using several different measurements

Answer 47

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

Question 48

Genetic polymorphism

Answer 48

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

Question 49

monomorphic locus

Answer 49

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

Question 50

polymorphic locus

Answer 50

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

Question 51

calculating the proportion of polymorphic gene loci

Answer 51

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

Question 52

Comparing the amino acid sequences of proteins to assess genetic diversity

Answer 52

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

Question 53

Comparing DNA sequences to assess biodiversity

Answer 53

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)

Question 54

reasons human population growth

Answer 54

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

Question 55

humans affect on biodiversity

Answer 55

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

Question 56

habitat destruction

Answer 56

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)

Question 57

overexploitation

Answer 57

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

Question 58

hunting

Answer 58

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)

Question 59

modern farming practices (agriculture)

Answer 59

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

Question 60

negative impacts of modern farming techniques

Answer 60

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

Question 61

decline of bumblebees

Answer 61

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

Question 62

biodiversity vs profit

Answer 62

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

Question 63

climate change

Answer 63

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

Question 64

global warming

Answer 64

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

Question 65

global warning threat to marine biology

Answer 65

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

Question 66

reasons for maintaining biodiversity

Answer 66

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

Question 67

ecological reasons

Answer 67

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

Question 68

economic reasons

Answer 68

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

Question 69

aesthetic reasons

Answer 69

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

Question 70

social reasons

Answer 70

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

Question 71

moral and ethical reasons

Answer 71

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

Question 72

environmental reasons

Answer 72

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

Question 73

agricultural reasons

Answer 73

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

Question 74

in situ conversion

Answer 74

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

Question 75

ex situ conservation

Answer 75

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

Question 76

conserved areas

Answer 76

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

Question 77

marine parks

Answer 77

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

Question 78

public engagement with conservation efforts

Answer 78

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

Question 79

galápagos islands

Answer 79

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.

Question 80

zoos and captive breeding

Answer 80

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

Question 81

botanic gardens

Answer 81

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

Question 82

storing genetic material for conservation

Answer 82

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

Question 83

a seed bank

Answer 83

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

Question 84

conservation agreements

Answer 84

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

Question 85

IUCN

Answer 85

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

Question 86

CBD

Answer 86

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

Question 87

CITES

Answer 87

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

Question 88

CSS

Answer 88

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