Biodiversity

Question 1

Define Ecosystem

Answer 1

All interacting living organisms and the non living conditions in an area

Question 2

Define community

Answer 2

All the populations of living organisms in a particular habitat

Question 3

Define habitat

Answer 3

The area inhabited by a species

Question 4

Define population

Answer 4

A group of organisms of one species that live in the same place at the same time

Question 5

Define species

Answer 5

The smallest and most specific taxonomic group

Question 6

Define the term biodiversity

Answer 6

The variety of living organisms present in an area

Question 7

Define the term habitat biodiversity

Answer 7

The number of different habitats found within an area

Question 8

Define the term species biodiversity

Answer 8

The number of different species and the abundance of different species in an area

Question 9

Define the term genetic biodiversity

Answer 9

Refers to the variety of genes that make up a species

Question 10

State the 3 levels of biodiversity.

Answer 10

Habitat, species and genetic biodiversity

Question 11

Name 3 examples of different habitats.

Answer 11

Meadow, woodland, streams and sand dunes

Question 12

Define the term “sampling” and explain why it is important.

Answer 12

Sampling means taking measurements of a limited number of individual organisms present in a particular area.

1. Can be used to estimate the number of organisms in an area without having to count them all- abundance
2. Can be used to measure particular characteristic of an organism- measuring height of plants and taking an avaerage

Question 13

State the two general ways in which sampling can be undertaken.

Answer 13

Random and non-random

Question 14

Define random smapling

Answer 14

Sampling where each individual in the population has an equal likelihood of selection.

Question 15

Define non-random sampling

Answer 15

The sample is not chosen at random, it can be opportunistic, stratified or systematic.

Question 16

Outline how to randomly sample an area.

Answer 16

Random number tables or computers can be used.

1. Mark out a grid on the grass using two tape measures laid at right angles.
2. Use random numbers to determine the x coordinate and the y coordinate on your rid
3. Take a sample at each of the coordinate pairs generated

Question 17

Name and describe the 3 main techniques of non-random sampling.

Answer 17

Opportunistic- This is the weakest form of sampling, as it may not be representative of the population - uses organisms that are conveniently available.
Stratified- Some populations can be divided into a number of strata based on a particular characteristic.- a random sample is then taken form each of theses strata proportional to its size.
Systematic- Different areas within an overall habitat are identified which are then sampled separately.

Question 18

Define the term Frame quadrat

Answer 18

A square rigid structure of fixed size used to identify an area to be sampled. It is usually dived in to a grid of equal sections

Question 19

Define the term point quadrat

Answer 19

A frame containing a horizontal bar. At set intervals along the bar, long pins can be pushed through the bar to reach the ground. Each species of plant the pin touches is recorded.

Question 20

Define the term line transect

Answer 20

This involves marking out a line along the ground between two poles and taking samples at specified points.

Question 21

Define the term belt transect

Answer 21

Provides more information than the line transect; two parallel lines are marked and samples are taken of the area between the two lines

Question 22

Define the term interrupted belt transect

Answer 22

Sampling using a frame quadrat at specific intervals along a line transect.

Question 23

Describe 5 ways to sample animals.

Answer 23

1. Pooter- catch small insects by sucking on a mouthpiece, draws insects into the holding chamber via the inlet tube
2. Sweep nets- catch insects in long grass
3. Pitfall traps- catch small crawling invertebrates in a hole that is dug in the ground- deep enough so they can come out and is covered with a roof structure to stop drowning.
4. Tree beating- a large white cloth is stretched out under the tree, the tree is shaken or beaten to dislodge invertebrate.
5. Kick sampling- the river bank and bed is kicked for a period of time to disturb the substrate. The net is held downstream for a set period of time in order to capture any organisms released into the flowing water

Question 24

Describe 2 ways to sample plants (and sessile, or very slow moving, animals).

Answer 24

1. point quadrat

2. Frame quadrat

Question 25

Describe 3 ways of collecting data using a frame quadrat (that could be applied to either random or non-random sampling).

Answer 25

1. Density- Count the number of plants in a quadrat- density per square metre- absolute measure not an estimate
2. Frequency- individual members of a species are hard to count like grass or moss. Using small grids within a quadrat count the number of squares a particular species is present in.
3. Percentage cover- for speed as lots of data can be collected quickly. Useful when a particular species is abundant or difficult to count. An estimate by eye of the area withing a quadrat that a species covers.

Question 26

Define abiotic factor

Answer 26

non-living conditions in a habitat

Question 27

Define biotic factor

Answer 27

The living components of an ecosystem

Question 28

Name, and state the equipment used to measure, 6 abiotic factors that could be measured when studying the abundance and distribution of organisms in an area.

Answer 28

1. Wind speed- anemometer ms-1
2. light intensity- light meter lx
3. Relative humidity- humidity sensor- mg dm-3
4. pH- pH probe
5. Temperature- temperature probe degrees Celsius
6. Oxygen content in water- dissolved oxygen probe mg dm-3

Question 29

Explain why a temperature probe linked to a data-logger may be advantageous over the use of a thermometer when investigating factors affecting the abundance and distribution of organisms in an area.

Answer 29

1. Rapid changes can be detected
2. Human error in taking a reading is reduced.
3. A high degree of precision can often be obtained.
4. Data can be stored and tracked on a computer

Question 30

Name and describe 2 ways of measuring species biodiversity.

Answer 30

1. Counting the number of species present- species richness- but doesn’t take into account the number of individuals present.
2. Simpson’s Index of Diversity- better as it takes into account both species richness and species evenness.

Question 31

State the information needed to determine the species richness and species evenness of an area.

Answer 31

1. Total number of organisms in one species
2. Total number of all organisms
3. And the sum of these two values

Question 32

Suggest how the population size of plants and animals can be estimated.

Answer 32

1. Using a variety of sampling techniques such as a quadrat to estimate the population of a plant species in an area.

Question 33

Explain why measuring species diversity allows us to obtain information about the stability of an ecosystem or the degree of pollution in an ecosystem.

Answer 33

1. A low biodiversity would suggest an unstable and polluted ecosystem.
2. As only a few organisms are present, so it must be an extreme environment as only a few species have survived in it.

Question 34

Describe the meaning of each of the symbols in the equation for calculating Simpson’s index of diversity.

Answer 34

E- sum of
N- total number of organisms of all species
n- the total number of organisms of a particular species
D- Simpson’s index of diversity 0-1

Question 35

Describe the range of values that Simpson’s index of diversity can take and explain how to interpret the value calculated.

Answer 35

0-1
0 represents no diversity and 1 represents infinite diversity.
closer to one the more diverse a habitat is and the greater it’s ability to cope with change

Question 36

Draw a table to show typical habitat features for areas with low and high biodiversity.

Answer 36

High biodiversity:

1. A large number of successful species
2. More benign and not stressful environment with more ecological niches
3. Many species live in the habitat with few specific adaptations to the environment.
4. Complex food webs
5. Often change has a relatively small effect to the ecosystem as a whole

Question 37

Explain why a greater genetic biodiversity increases a species chances of long term survival.

Answer 37

1. Species that contain greater genetic biodiversity are likely to be bale to adapt to changes in their environment and hence are less likely to become extinct.
2. This is because they are likely to be some organisms within the population that carry an advantageous allele, which enables them to survive in the altered conditions.

Question 38

Name and describe the two ways in which the genetic biodiversity of a population can be increased.

Answer 38

1. Mutation- in the DNA of an organism creating a new allele
2. Interbreeding between different populations. When an individual migrates from one population and breeds with a member of another populations alleles are transferred between the two populations - gene flow

Question 39

Describe 6 factors that may cause a decrease in genetic diversity.

Answer 39

1. Selective breeding- where a few individuals within a population are selected for their advantageous characteristics and bred.
2. Captive breeding programmes- a small number of captive individuals of a species are available for breeding in zoos and conservation centres
3. Artificial cloning- asexual reproduction using cutting to clone a farmed plant
4. Natural selection- Species evolve to contain the alleles which code for advantageous characteristics.-
5. Genetic bottlenecks- where a few individuals within a populations survive an event or change thus reducing the gene pool.
6. Founder effect- a small number of individuals create a new colony geographically isolated from the original. The gene pool for this population is small
7. Genetic drift- due to random nature of alleles being passed on from parents the frequency of occurrence of an allele will vary- some cases the existence of a particular allele can disappear from a population altogether

Question 40

Define polymorphic

Answer 40

A gene with more than two possible alleles

Question 41

Define locus

Answer 41

The locus of a gene refers to the position of the gene on the chromosome

Question 42

Write an equation that provides a measure of genetic diversity.

Answer 42

1. Measuring polymorphism. Genes that aren’t polymorphic are said to be monomorphic- a single allele exists for this gene- ensures basic structure of individuals within a species remains consistent.
2. Proportion of polymorphic gene loci= Number of polymorphic gene loci/ total number of loci

Question 43

Describe the range of values that the “proportion of polymorphic gene loci” can take and explain how to interpret the value calculated.

Answer 43

0-1
The higher the number, the greater the proportion of polymorphic gene loci and so the greater the genetic biodiversity within a population.

Question 44

Describe the change in the human population since 1800.

Answer 44

The populations now is over 7 times more than in 1800 and over double what it was in 1960s.

Question 45

Describe 3 main issues for biodiversity that have come about due to an increased human population size.

Answer 45

1. Deforestation
2. Agriculture- increasing amount of land has to be farmed and this has resulted in large amounts of land being cleared and in many cases planed with a single crop monoculture
3. Climate change

Question 46

Describe 4 ways in which deforestation affects biodiversity.

Answer 46

1. Reduces the number of trees
2. If only a specific type of tree is felled the species diversity is reduced.
3. It reduces the number of animal species present in an area as it destroys their habitat, this in turn reduces or removes other animals food sources.
4. Animals are forced to migrate to other areas to ensure their survival, this may result in the biodiversity of neighbouring areas increasing.

Question 47

Describe 5 methods associated with agriculture which affect biodiversity.

Answer 47

1. Deforestation
2. Removal of hedgerows- enables them to use large machinery and frees up land. This reduces the number of plant species present in an area and destroys the habitat of animals.
3. Use of chemicals such as pesticides and herbicides- kills pests which reduces species diversity directly and indirectly by destroying the food source of other organisms.
4. Monoculture- many farms specialise in the production of only one crop. This lowers the biodiversity as only one species of plant is present. Few animal species will be supported by only one type of plant- low overall biodiversity levels.

Question 48

Define global warming

Answer 48

The rising in the Earth’s mean surface temperature.

Question 49

Define climate change

Answer 49

A change in global or regional climate patterns, and attributed largely to the increased levels of atmospheric carbon dioxide produced by the use of fossil fuels.

Question 50

Describe the evidence for climate change and the role of human activities in climate change.

Answer 50

1. The warming trend over the last 50 years is nearly twice that for the previous 100 years
2. The average amount of water vapour in the atmosphere has increased over land and ocean- warmer air can hold extra water vapour.
3. The global average sea level rose more than in 19th century.
4. Average temperature of oceans has increased
5. Mountain cover and snow glaciers have declined on average
6. Upward trend in the amount of precipitation

Question 51

Describe 4 ways in which biodiversity may be affected by climate change.

Answer 51

1. Melting of the ice polar caps can lead to the extinction of the few plants and animal species living in these regions
2. Rising sea levels from melting ice caps and thermal expansion of oceans could flood low-lying lands, reducing the available habitats. Saltwater would flow further up rivers reducing the habitats of freshwater plants and animals.
3. Higher temps and less rainfall would result in some plant species failing to survive leading to drought-resistant plants becoming more dominant. This would lead to loss of animal species dependent on them as a food source
4. Insect life cycles and populations will change as they adapt to climate change. As insects are key pollinators of many plants this could affect the lives of the plants it leaves behind causing extinction. As tropical insects spreads so do tropical diseases.

Question 52

State the 3 categories of reasons for maintaining biodiversity.

Answer 52

Aesthetic, economic, ecological

Question 53

Describe 3 aesthetic reasons for maintaining biodiversity.

Answer 53

1. The presence of different plants and animals in our environment enriches out lives- relax on beach or have a walk
2. The natural world provides inspiration for people such as writers and artists
3. Studies have shown that patients recover more rapidly from stress and injury when they are supported by plants and a relatively natural environment

Question 54

Describe 8 economic reasons for maintaining biodiversity.

Answer 54

1. Soil erosion and desertification may occur as a result of deforestation- reduce a country’s ability to grow crops and feed its people which can lead to resource ad economic dependence on other nations
2. Non-sustainable removal of resources will eventually lead to the collapse of industry in an area. Once the raw material has been lost it is not economically viable to continue the industry.
3. Large-scale habitat and biodiversity losses mean that species with potential economic importance may become extinct before they are discovered.
4. Continuous monoculture results in soil depletion- a reduction in the diversity of soil nutrients. This makes the crop support weaker, increasing vulnerability to opportunistic insects, plant competitors and microorganisms. Farmer will become dependent on expensive pesticides, fertilisers etc.
5. High biodiversity provides protection against abiotic stress. When not maintained a change in conditions or a disease can destroy entire crops.
6. High bio diverse places can promote tourism in the region.
7. The greater the diversity of an ecosystem, the greater the potential for the manufacture of different products in the future.
8. Plant varieties are needed for cross-breeding which can lead to better characteristics such as disease resistance. Wild relatives of cultivated crop plants provide genetic material to aid the production of new varieties of crops.

Question 55

Define the term “keystone species” and explain why they are important in maintaining biodiversity.

Answer 55

Species which are essential for maintaining biodiversity- they have a disproportionately large effect on their environment relative to their abundance.
e.g. Sea stars eat mussels and sea urchins, which have no other natural predators. If the sea star was removed from the ecosystem, the mussel undergoes a population explosion, reducing the number of other species in the area as they compete for space and other resources.

Question 56

Describe 2 ecological reasons for maintaining biodiversity.

Answer 56

1. All organisms are interdependent on others for survival. The removal of one may have a significant effect on others, for example a food source or a place to live may be lost. e.g plants rely on bees for pollination, declining bee population would decrease crop yield.
2. Keystone species affect many other organisms in an ecosystem and help to determine the species richness and evenness in the community. When removed the habitat is drastically changed- other species are affected and some may disappear altogether.

Question 57

Define the term conservation`

Answer 57

Is the maintenance of biodiversity by preservation and careful management of the environment and of natural resources.

Question 58

Describe the difference between in situ and ex situ conservation

Answer 58

in situ- within the natural habitat

ex situ- out of the natural habitat

Question 59

Name 2 methods of in situ conservation.

Answer 59

Wildlife reserves

Marine conservation zones

Question 60

Describe 7 methods of active management in wildlife reserves.

Answer 60

1. Controlled grazing- only allow livestock to graze a particular area of land for a certain period of time to allow species time to recover.
2. Restricting human access- providing paths so plants aren’t trampled etc.
3. Controlling poaching- creating defences to prevent access, issuing fines etc.
4. Feeding animals- help to ensure more organisms survive to reproductive age
5. Reintroduction of species- adding species to areas that have become locally extinct, or whose numbers have decreased rapidly.
6. Culling or removal of invasive species- invasive species are not native and have negative effects on the economy, environment or health. They compete with native species for resources.
7. Halting succession- protect habitat such as heath from becoming woodland through controlled grazing.

Question 61

Describe the role of marine conservation zones in maintaining biodiversity.

Answer 61

1. Purpose is to create areas of refuge withing which populations can build-up and repopulate adjacent areas.
2. Vital in preserving species-rich areas such as coral reefs which are being devastated by non-sustainable fishing methods.
3. Large areas of sea are required for marine reserve as the target species often move large distances or breed in geographically different areas.

Question 62

Name 3 methods of ex situ conservation.

Answer 62

1. Botanic gardens
2. Seed banks
3. Captive breeding programmes

Question 63

Describe the role of botanic gardens in maintaining biodiversity.

Answer 63

1. Plant species can be grown successfully as they are actively managed to provide them with the best resources to grow.
2. Such as the provision of soil nutrients, sufficient watering and the removal or prevention of pests
3. But many wild relatives of selectively bred crop species are under-represented amongst the conserved species.
4. These wild species are a potential source of genes, conferring resistance to diseases, pests and parasites

Question 64

Describe the role of seed banks in maintaining biodiversity.

Answer 64

1. An example of a gene bank.
2. Seeds are carefully stored so that new plants may be grown in the future.
3. They are stored at low temperatures to maintain their viability, by slowing down the rate at which they lose their ability to germinate.
4. Provides back up for the extinction of plants in the wild.
5. But don’t work for all plants as some seeds die when dried and frozen and most seeds in rain-forest fall into this category.

Question 65

Describe the role of captive breeding programmes in maintaining biodiversity.

Answer 65

1. Produce offspring of species in a human-controlled environment. Often in zoos or aquatic centres.
2. Several species are now solely represented by animals in captivity.
3. The aim is to create a stable, healthy population of a species and then gradually reintroduce the species back into its natural habitat.
4. They provide the animals with shelter, and abundant supply of nutritious food, an absence of predators and veterinary treatment.

Question 66

Describe how captive breeding programmes try to maintain (or increase) genetic diversity.

Answer 66

1. Maintaining genetic diversity within a programme can be difficult- only a small number of breeding partners are available, so problems with inbreeding
   can occur.
2. An international catalogue is maintained, detailing genealogical data on individuals.
3. Mating can thus be arranged to ensure the genetic diversity is maximised .
4. Techniques such as artificial insemination, embryo transfer and long-term cryogenic storage of embryos allow new genetic lines to be introduced without having to transport adults to new locations and do not require the animals’ cooperation

Question 67

Explain why it may not be possible to release some captively bred organisms back into the wild.

Answer 67

1. Diseases- there may be a loss of resistance ot local diseases in captive-bred populations. New diseases might exist in the wild, to which captive animals have yet to develop resistance.
2. Behaviour- Much behaviour has to be learnt- early stages of reintroduction monkeys starved to death as they had no concept of having to search for food.
3. Genetic races- The genetic make-up of captive animals can become so different form the original population hat the two populations cannot interbreed
4. Habitat- in many cases the natural habitat must first be restored to allow captive populations to be reintroduced. If only a small habitat exists it is likely that there are already as many individuals as that habitat can support. Introduction of new individuals can lead to tensions as individuals fight for limited territory and resources such as food.

Question 68

State the full name of the IUCN and outline their role in conservation.

Answer 68

International Union for the Conservation of Nature:

1. assist in securing agreements between nations.
2. Publish the Red List, detailing the current conservation status of threatened animals. Countries can then work together to conserve these species.
3. Also involved in establishment of the Convention on International Trade in Endangered Species.
4. This treaty regulates the international trade of wild plants and animal specimens and their products.
5. The effort to regulate it requires international cooperation to safeguard certain species form over-exploitation.