Biodiversity

Question 1

What is biodiversity?

Answer 1

1) Biodiversity — the variety of living organisms in an area.

Question 2

What is a species?

Answer 2

2) Species — a group of similar organisms able to reproduce to give fertile offspring.

Question 3

What is a habitat?

Answer 3

3) Habitat — the area inhabited by a species. It includes the physical factors, like the soil and temperature range, and the living (biotic) factors, like availability of food or the presence of predators.

Question 4

What is Habitat diversity?

Answer 4

1) Habitat diversity — the number of different habitats in an area. For example, a particular area could contain many different habitats — sand dunes, woodland, meadows, streams, etc.

Question 5

What is species diversity?

Answer 5

2) Species diversity — the number of different species (species richness) and the abundance of each species (species evenness) in an area. For example, a woodland
could contain many different species of plants, insects, birds and mammals.

Question 6

What is genetic diversity?

Answer 6

3) Genetic diversity — the variation of alleles within a species (or a population of a species). For example,
the variation of alleles within the dog species gives rise to different breeds, such as a Labrador or poodle.

Question 7

How can sampling be used to measure biodiversity?

Answer 7

1) Choose an area to sample — a small area within the habitat being studied.
2) Count the number of individuals of each species (see below).
3) Repeat the process — take as many samples as possible. This gives a better indication of the whole habitat.
4) Use the results to estimate the total number of individuals or the total number of different species in the
habitat being studied.
5) When sampling different habitats and comparing them, always use the same sampling technique.
You could investigate the impact of mowing on the biodiversity of your school playing field by sampling a mowed
and an un-mowed field. Calculate the biodiversity for each field using Simpson’s Index

Question 8

Why do different organisms need different sampling methods?

Answer 8

How you find out how many individuals are in your sample area depends on the organism you are studying. E.g.
1) For crawling ground insects you could use a pitfall trap (a small pit that insects can’t get out of)
or a pooter (a device that allows you to safely suck small insects through a tube into a jar).
2) For small organisms that live in soil or leaf litter you could use a Tullgren funnel — this is where a soil or
leaf litter sample is put on a mesh filter at the top of a funnel and a light is shone down onto it. Organisms
move away from the heat created by the light and fall out of the funnel and into a collecting beaker.
3) For some aquatic organisms you could use kick sampling (you gently kick the bottom of a stream then use
a net to collect the organisms that have been disturbed).
4) For organisms living in long grass you could use a sweep net (a net lined with strong cloth on a pole).

Question 9

Why can a sample be random/non

Answer 9

1) To avoid bias in your results, the sample should be random. For example, if you were looking at plant species
in a field, you could pick random sample sites by dividing the field into a grid using measuring tapes and
using a random number generator to select coordinates.
2) However, sometimes it’s necessary to take a non-random sample. E.g. when there’s a lot of variety in the
distribution of species in the habitat and you want to make sure all the different areas are sampled.

Question 10

How many types of non random sampling are there?

Answer 10

3

Question 11

What are the 3 types of non random sampling?

Answer 11

systematic
opportunity
stratified

Question 12

What is a systematic sample?

Answer 12

1) Systematic — This is when samples are taken at fixed intervals, often along a line. E.g. if you were counting plant species in a field, quadrats (frames which you place on the ground) could be placed along a line (called a transect) from an area of shade in the corner to the middle of the field. Each quadrat would be a sample site.

Question 13

Whats a opportunity sample?

Answer 13

2) Opportunistic — This is when samples are chosen by the investigator.
It’s used because it is simple to carry out, but the data will be biased.

Question 14

What is a stratified sample?

Answer 14

3) Stratified — This is when different areas in a habitat are identified and sampled separately in proportion to
their part of the habitat as a whole. E.g. a heathland may have patches of gorse in it — the heath and gorse
areas would be sampled separately according to how much of each there was in the habitat.

Question 15

What is species richness?

Answer 15

1) Species richness is the number of different species in an area. The higher the number of species,
the greater the species richness. It’s measured by taking random samples of a habitat (see previous page)
and counting the number of different species.

Question 16

What is species eveness?

Answer 16

2) Species evenness is a measure of the relative abundance of each species in an area. The more similar the
population size of each species, the greater the species evenness. It’s measured by taking random samples
of a habitat, and counting the number of individuals of each different species.

Question 17

what is simpsons diversity index?

Answer 17

1) Species present in a habitat in very small numbers shouldn’t
be treated the same as those with bigger populations.
2) Simpson’s Index of Diversity takes into account both
species richness and species evenness.
3) Simpson’s Index of Diversity (D) can be calculated using this formula.
4) Simpson’s Index of Diversity is always a value between 0 and 1.
The closer to 1 the index is, the more diverse the habitat.
The greater the species richness and evenness, the higher the number.

Question 18

Simpsons equation

Answer 18

D=1- (Σ (n/N)^2)

n = Total number of individuals of
one species
N = Total number of organisms of
all species
Σ  = ‘Sum of’ (i.e. added together)

Question 19

Genetic Diversity Can be Assessed

Answer 19

Genetic Diversity Can be Assessed
1) You know from page 110 that genetic diversity is the variation of alleles
within a species (or within a population of a species).
2) You can do calculations to work out the genetic diversity of a population.
3) This is important because if a population has low genetic diversity, they might
not be able to adapt to a change in the environment and the whole population
could be wiped out by a single event (e.g. a disease).
4) Populations in which genetic diversity may be low include isolated populations
such as those bred in captivity (e.g. in zoos, and pedigree animals and rare breeds).
5) Calculations can be used to monitor the genetic diversity of these populations over time and efforts can be
made to increase the genetic diversity of the population if needed. E.g. breeding programmes in zoos are
very closely managed to maximise genetic diversity.

Question 20

How is Genetic Polymorphism is Used to Measure Genetic Diversity

Answer 20

Genetic Polymorphism is Used to Measure Genetic Diversity
1) You know that alleles are different versions of a gene.
2) Alleles of the same gene are found at the same point (called a locus) on
a chromosome.
3) Polymorphism describes a locus that has two or more alleles.
4) Working out the proportion of polymorphic gene loci in an
organism (i.e. those points on a chromosome which can have
more than one allele) gives you a measure of genetic diversity.
5) There’s a nifty formula you can use:

Question 21

Genetic Polymorphism equation?

Answer 21

proportion of polymorphic gene loci =
number of polymorphic gene loci/ total number of loci
Example:
If 40 of the genes sampled in a population are polymorphic out of
100 genes sampled in total, then the proportion of polymorphic gene loci =40/100
= 0.4

Question 22

What 3 factors affect biodiversity?

Answer 22

Human population growth
increased agriculture
climate change

Question 23

How does Human Population Growth affect biodiversity?

Answer 23

1) Human Population Growth
The human population of the planet has grown hugely in the last couple of centuries and is continuing to rise.
This is decreasing global biodiversity because of the following factors: )
Habitat loss — human development is destroying habitats, e.g. there is deforestation in the Amazon to make way for grazing and agriculture. This decreases habitat diversity.
2) Over-exploitation — a greater demand for resources (such as food, water and energy) means a lot of resources are being used up faster than they can be replenished. E.g. industrial fishing can deplete the
populations of certain fish species and may even cause extinction (a species to die out). This decreases genetic diversity within populations, as well as decreasing species diversity (as a result of extinction).
3) Urbanisation — sprawling cities and major road developments can isolate species, meaning populations are unable to interbreed and genetic diversity is decreased.
4) Pollution — high amounts of pollutants can kill species or destroy habitats, e.g. high levels of fertiliser flowing into a river can lead to a decrease in fish species in that river. This decreases biodiversity.

Question 24

How does Increased Use of Monoculture in Agriculture affect biodiversity?

Answer 24

2) Increased Use of Monoculture in Agriculture
In order to feed an ever growing number of people, large areas of land are devoted to monoculture — the growing of a single variety of a single crop. E.g. in Africa, large areas of land are used for palm oil plantations. This leads to a decline in global biodiversity because of the following factors:
1) Habitats are lost as land is cleared to make way for the large fields, reducing habitat diversity.
2) Local and naturally occurring plants and animals are seen as weeds and pests, and so are
destroyed with pesticides and herbicides, reducing species diversity.
3) Heritage (traditional) varieties of crops are lost because they don’t make enough money and
so are not planted any more, which reduces species diversity.

Question 25

How does climate change affect biodiversity?

Answer 25

) Climate Change
1) Climate change is the variation in the Earth’s climate, e.g. things like changes in
temperature and rainfall patterns.
2) It occurs naturally, but the scientific consensus is that the climate change we’re experiencing at the
moment is caused by humans increasing emissions of greenhouse gases (such as carbon dioxide).
3) Greenhouse gases cause global warming (increasing global average temperature), which causes other
types of climate change, e.g. changing rainfall patterns.
4) Climate change will affect different areas of the world in different ways — some places will get
warmer, some colder, some wetter and others drier. All of these are likely to affect global biodiversity

Question 26

What might happen to a species if there is a change in climate?

Answer 26

• Most species need a particular climate to survive.
• A change in climate may mean that an area that was previously
inhabitable becomes uninhabitable (and vice versa).
• This may cause an increase or decrease in the range of some species (the area in which they live). This could increase or decrease biodiversity. • Some species may be forced to migrate
to a more suitable area, causing a change in species distribution. Migrations usually decrease biodiversity in the areas the species
migrate from, and increase biodiversity in the areas they migrate to. • If there isn’t a suitable habitat to migrate to, the species is a plant and can’t migrate, or if the change is too fast, the species may become extinct. This will decrease biodiversity.

Question 27

Why is maintaining biodiversity important for ecological reasons?

Answer 27

1) To Protect Species, Including Keystone Species

2) To Maintain Genetic Resources

Question 28

Why is it important To Protect Species, Including Keystone Species

Answer 28

Organisms in an ecosystem are interdependent — they depend on each other to
survive. This means that the loss of just one species can have pretty drastic effects
on an ecosystem, such as:
1) Disruption of food chains, e.g. some species of bear feed on salmon, which feed on
herring. If the number of herring decline it can affect both the salmon and the bear populations.
2) Disruption of nutrient cycles, e.g. decomposers like worms improve the quality of soil by recycling nutrients. If worm numbers decline, soil quality will be affected. This will affect the growth of plants and the amount of food available to animals. There are some species on which many of the other species in an ecosystem depend and without which
the ecosystem would change dramatically — these are called keystone species. Keystone species are often predators — keeping the population of prey in check, but can also be modifiers — maintaining the environment needed for the ecosystem (e.g. beavers building dams), or hosts — plants that provide a particular environment, such as palm trees.

Question 29

Why is it important to maintain genetic resources?

Answer 29

Genetic resources refer to any material from plants, animals or microorganisms, containing genes, that we find valuable. Genetic resources could be crops, plants used for medicines, micro-organisms used in industrial processes, or animal breeds. We need to maintain genetic resources for the following reasons:
1) Genetic resources provide us with a variety of everyday products, such as: • Food and drink — plants and animals are the source of almost all food and some drinks.
• Clothing — a lot of fibres and fabrics are made from plants and animals (e.g. cotton from plants and leather from animals).
• Drugs — many are made from plant compounds (e.g. the painkiller morphine is made from poppies).
• Fuels — we use a number of organisms to produce renewable fuels, including ethanol and biogas. Fossil fuels are non-renewable (they’ll run out), so other sources are of major economic importance.
• Other industrial materials — a huge variety of other materials are produced from plant and animal species, including wood, paper, dyes, adhesives, oils, rubber and chemicals such as pesticides. Many genetic resources are important to the global economy. Products derived from plant and animal species are traded on a local and global scale.
2) Genetic resources allow us to adapt to changes in the environment. For example, climate change may mean that some crops won’t be able to grow in the same areas as they do now, e.g. there might be droughts in those areas. However, we may be able to use genes from a plant that’s resistant to droughts to genetically engineer a drought-resistant crop — that’s if we have such genetic resources to choose from.

Question 30

What is a reason to maintain biodiversity economic reasons?

Answer 30

To Reduce Soil Depletion
1) Monoculture is growing a single variety of a single crop (see p. 113).
2) Continuous monoculture involves planting the same crop in the same field without interruption.
3) Continuous monoculture causes soil depletion because the nutrients required by the crop are gradually used up. (In more traditional farming methods crops are rotated with other types of crops, so that the nutrients and organic matter are replaced.)
4) The economic costs of soil depletion include increased spending on fertilisers (to artificially replace nutrients) and decreased yields
(in the long run and if fertilisers are not used).

Question 31

What is a reason to maintain biodiversity aesthetic reasons?

Answer 31

Some people believe we should conserve biodiversity because it brings joy to millions of people.
1) Areas rich in biodiversity provide pleasant, attractive landscapes
that people can enjoy. By maintaining biodiversity we protect
these beautiful landscapes.
2) The more biodiversity in an area the more visitors the area is likely
to attract — this also has economic advantages.

Question 32

How many coconservations are there?

Answer 32

4

Question 33

What are the 4 conservations?

Answer 33

In Situ Conservation Natural Habitat Keeps Species in Their natural habitat
Ex Situ Conservation Removes Species from Their Natural Habitat
International Cooperation is Important in Species Conservation
Local Conservation Agreements Protect Special Areas in the UK

Question 34

What is In Situ Conservation Natural Habitat?

Answer 34

In situ conservation means on site conservation — it involves protecting species in their natural habitat. Conservation is important to ensure the survival of endangered species — species which are at risk of extinction because of a low population, or a threatened habitat. Methods of in situ conservation include:

1) Establishing protected areas such as national parks and wildlife reserves (also known as nature reserves) — habitats and species are protected in these areas by restricting urban development, industrial development and farming. A similar idea has been introduced to sea ecosystems with Marine Conservation Zones, where human activities (like fishing) are controlled. 2) Controlling or preventing the introduction of species that threaten local biodiversity. For example, grey squirrels are not native to Britain. They compete with the native red squirrel and have caused a population decline. So they’re controlled in some areas. 3) Protecting habitats — e.g. controlling water levels to conserve wetlands and coppicing (trimming trees) to conserve woodlands. This allows organisms to continue living in their natural habitat.
4) Promoting particular species — this could be by protecting food sources or nesting sites.
5) Giving legal protection to endangered species, e.g. making it illegal to kill them

Question 35

What is one advantage and disadvantage of Situ Conservation Natural Habitat?

Answer 35

One advantage of in situ conservation is that often both the species and their habitat are conserved.
Larger populations can be protected and it’s less disruptive than removing organisms from their habitats.
The chances of the population recovering are greater than with ex situ methods (see below).
But it can be difficult to control some factors that are threatening a species (such as poaching, predators,
disease or climate change).

Question 36

What is Ex Situ Conservation?

Answer 36

Ex Situ Conservation Removes Species from Their Natural Habitat
Ex situ conservation means off site conservation — it involves protecting a species by removing part of the population from a threatened habitat and placing it in a new location. Ex situ conservation is often a last resort. Methods of ex situ conservation include:
1) Relocating an organism to a safer area, e.g. five white rhinos were recently relocated from the Congo to Kenya because they were in danger from poachers who kill them for their ivory.
2) Breeding organisms in captivity then reintroducing them to the wild when they are strong enough, e.g. sea eagles have been reintroduced to Britain through a captive breeding programme.
Breeding is carried out in animal sanctuaries and zoos.
3) Botanic gardens are controlled environments used to grow a variety of rare plants for the purposes of conservation, research, display and education. Endangered plant species as well as species that are extinct in the wild can be grown and reintroduced into suitable habitats.
4) Seed banks — seeds can be frozen and stored in seed banks for over a century without losing their fertility. Seed banks provide a useful source of seeds if natural reserves are destroyed, for example
by disease or other natural disasters.

Question 37

What is one + and - of Ex Situ Conservation?

Answer 37

The advantages of ex situ conservation are that it can be used to protect individual animals in a controlled
environment — things like predation and hunting can be managed more easily. It can also be used to reintroduce
species that have left an area.
But, there are disadvantages — usually only a small number of individuals can be cared for. It can be difficult and
expensive to create and sustain the right environment. In fact, animals that are habituated (used to) human contact
may be less likely to exhibit natural behaviour and may be more likely to catch a disease from humans. Ex situ
conservation is usually less successful than in situ methods — many species can’t breed successfully in captivity, or
don’t adapt to their new environment when moved to a new location.

Question 38

What is International Cooperation?

Answer 38

International Cooperation is Important in Species Conservation
Information about threats to biodiversity needs to be shared and countries need to decide on conservation methods
and implement them together. Here are a couple of examples of successful international cooperation:

Question 39

What is International Cooperation split into?

Answer 39

Rio Convention on Biological Diversity (CBD)

CITES Agreement

Question 40

What is Rio Convention on Biological Diversity (CBD)

Answer 40

1) It aims to develop international strategies
on the conservation of biodiversity and
how to use animal and plant resources in
a sustainable way.
2) The convention made it part of
international law that conserving
biodiversity is everyone’s responsibility.
3) It also provides guidance to governments
on how to conserve biodiversity.

Question 41

What is CITES Agreement?

Answer 41

CITES Agreement
1) CITES (Convention on International Trade in
Endangered Species) is an agreement designed to
increase international cooperation in regulating
trade in wild animal and plant specimens.
2) The member countries all agreed to make it illegal to
kill endangered species.
3) The agreement helps to conserve species by limiting
trade through licensing, and by making it illegal to
trade in products made from endangered animals
(such as rhino ivory and leopard skins).
4) It’s also designed to raise awareness of threats to
biodiversity through education.

Question 42

Why is international cooperation important?

Answer 42

International cooperation is really important — it’d be pointless making hunting endangered species illegal in one
country if poachers could just go and hunt them in another country.