Module 4: Section 2 - Biodiversity

Question 1

Define biodiversity

Answer 1

Biodiversity - the variety of living organisms in an area

Question 2

Define species

Answer 2

Species - a group of similar organisms able to reproduce to give fertile offspring

Question 3

Define habitat

Answer 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 yhe presence of predators

Question 4

Define habitat diversity

Answer 4

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

Question 5

Define species diversity

Answer 5

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

Define genetic diversity

Answer 6

genetic diversity - the variation of alleles within a species (or a population of a species). E.g., the variation of alleles within the dog species gives rise to different breeds, such as a labrador or poodle

Question 7

Estimates about the whole habitat are based on the sample. What does sampling involve?

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. How you do this depends on what you’re counting for example: for plants - quadrat, for flying insects - sweep net, for ground insects - pitfall and for aquatic animals - net
3) repeat the process. More samples 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 ise the same sampling technique

Question 8

What should you do to avoid bias in your results of sampling?

Answer 8

To avoid bias in your results, the sample should be random. E.g., 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

Question 9

When is it necessary to take a non-random sample?

Answer 9

For example, 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

Please explain the three types of non-random sample

Answer 10

1) systematic - this is when samples are taken at fixed intervals, often along a line. e.g. quadrats could be placed along a line (called a transect) from an area of shade in the corner to the middle of the field
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
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 11

What is species richness and what does it mean?

Answer 11

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 and counting the number of different species

Question 12

What is species evenness and what does it mean?

Answer 12

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 13

You know that genetic diversity is the variation of alleles within a species and you can do calculations to work out the genetic diversity of the population - why is this important?

Answer 13

1) 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)
2) populations in which genetic diversity is low include isolated populations such as those bred in captivity
3) 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 need

Question 14

You know that alleles are different versions of a gene.

Alleles of the same gene are found at the same point (called a locus) on a chromosome.

What does polymorphism describe and how would you work out the proportion of polymorphic gene loci?

Answer 14

1) polymorphism describes a locus that has two or more alleles
2) working out the proportion of polymorphic gene loci in an organism gives you a measure of genetic diversity and there’s even a nifty formula you can use:

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

Here’s an 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 15

Human population growth has grown hugely and is continuing to rise. This is decreasing global biodiversity - give four factors why please

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Answer 15

1) habitat loss - human development is destroying habitats, e.g. there is deforestation in the Amazon. 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. 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. This decreases biodiversity

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Question 16

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. These leads to a decline in global diversity because of which three factors?

Answer 16

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 varieties of crops are lost because they don’t make enough money and so are not planted anymore, which reduces species diversity

Question 17

Briefly explain to me what climate change is

Answer 17

1) climate change is the variation in the Earth’s climate
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
3) greenhouse gases cause global warming, which causes other types of climate change
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

Question 18

How will climate change affect global biodiversity?

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Answer 18

• most species need a particular climate to survive
• a change in climate may mean that an area that was previously inhabitable becomes uninhabitable
• this may cause an increase or decrease in the range of some species. 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 decreases 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 19

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. Please give two examples

Answer 19

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 population
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

Question 20

What are keystone species and what are they often?

Use the words predator, modifier and host in your answer please

Answer 20

There are some species on which many of the other species in an ecosystem depend on 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 be modifiers - maintaining the environment needed for the ecosystem, or hosts - plants that provide a particular environment

Question 21

Explain the example of the keystone species of wolves in America

Answer 21

The wolf is a keystone species in America. Wolf populations were eliminated in most American states during the 20th century. Without the wolves to hunt them, elk populations increased, leading to overgrazing. This led to the loss of plant species, as well as the loss of species that depend on those plants such as beavers and songbirds. The situation has since been reversed in some national parks

Question 22

Maintaining biodiversity is important for ecological reasons like maintaining genetic resources. What does the phrase genetic resources refer to?

Answer 22

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, microorganisms used in industrial processes, or animal breeds

Question 23

Genetic resources provide us with a variety of everyday products, such as..?

Answer 23

food and drink, clothing, drugs, fuels and other industrial materials, e.g. wood, paper

Question 24

Genetic resources allow us to adapt to changes in the environment. Please explain the example of climate change

Answer 24

for example, climate change may mean that some crops won’t be able to grow in the same areas as they do now. However, we may be able to use genes from a plant that’s resistant to these factors through genetic engineering - that’s if we have such genetic resources to choose from

Question 25

Maintaining biodiversity is important for economic reasons, for example to reduce soil depletion. How does maintaining biodiversity reduce soil depletion?

Answer 25

1) monoculture is growing a single variety of a single crop 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 4) the economic costs of soil depletion include increased spending on fertilisers and decreased yields (in the long run if fertilisers are not used)

Question 26

Some people believe we should conserve biodiversity for aesthetic reasons. What is the argument for this?

Answer 26

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 27

In situ conservation means on site conservation - it involves protecting species in their natural habitat. Conservation is important to ensure the survival of the endangered species. What are five methods of in situ conservation and please give an example of each one?

Answer 27

1) establishing protected areas such as national parks or wildlife reserves - habitats and species are protected in these areas by restricting urban development, industrial development and farming. 2) controlling or preventing the introduction of species that threaten the local biodiversity 3) protecting habitats - e.g. coppicing (trimming trees) to conserve woodlands 4) promoting particular species - this could be done by protecting food sources or nesting sites 5) giving legal protection to endangered species, e.g. making it illegal to kill them

Question 28

Please explain the advantages and disadvantages of in situ conservation

Answer 28

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 But it can be difficult to control some factors that are threatening a species (such as poaching, disease, predators, climate change...)

Question 29

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. What are four methods of ex situ conservation and please give an example of each?

Answer 29

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 2) breeding organisms in captivity then reintroducing them into the wild when they are strong enough. 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 4) seed banks - seeds can be frozen and stored in seed banks for over a century without losing their fertility

Question 30

Please explain the advantages and disadvantages of ex situ conservation

Answer 30

The advantages of ex situ conservation are that it can be used to protect individual animals in a controlled environment - things like predation can be managed more easily. It can also be used to reintroduce a 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 31

What is the Rio Convention on Biological Diversity and what are its aims?

Answer 31

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 32

What is the CITES agreement and what are its aims?

Answer 32

1) CITES is an agreement designed to increase international co-operation 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 4) it's also designed to raise awareness of threats to biodiversity through education

Question 33

What is the Countryside Stewardship Scheme (CSS) and what are its aims?

Answer 33

1) the CSS was introduced in 1991. Some of its aims were to conserve wildlife and biodiversity, and to improve and extend wildlife habitats by promoting specific management techniques to landowners 2) the government offered 10-year agreements to pay landowners who followed the management techniques they were suggesting 3) in the year 2000, there were 10 000 agreements in England. Since the introduction of the scheme, various species have begun to rebuild in numbers, including birds such as the stone curlew, black grouse and bittern

Question 34

Relax! Go take a break

Answer 34

Try not to stress, it's not productive Have a coffee and go running