chapter 11 p3

Question 1

Climate change:

Answer 1

In 2007, the Intergovernmental Panel on Climate Change (IPCC) released a report summarising scientists’ current understanding of climate change.
The report took six years to produce and involved over 2500 scientific personnel in its production.
Some of the key findings include the following:

Question 2

Some of the key findings include the following: p1

Answer 2

• The warming trend over the last 50 years (about 0.13°C per decade) is nearly twice that for the previous 100 years.
• The average amount of water vapour in the atmosphere has increased since the 1980s over land and ocean. The increase is broadly consistent with the extra water vapour that warmer air
• Since 1961, the average temperature of the global ocean down to depths of 3 km has increased.
  The ocean has been absorbing more than 80% of the heat added to the climate system, causing seawater to expand and contributing to sea-level rise.
• The global average sea level rose by an average of 1.8mm per year from 1961 to 2003. - There is high confidence that the rate of observed sea level rise increased from the 19th to the 20” century.
• Average Arctic temperatures have increased at almost twice the global average rate in the past 100 years.
• Mountain glaciers and snow cover have declined on average in both hemispheres.
  Widespread decreases in glaciers and ice caps have contributed to sea-level rise.
• Long-term upward trends in the amount of precipitation have been observed over many regions from 1900 to 2005.

Question 4

climate change research p1

Answer 4

To enable our understanding of climate change to develop. significant quantities of data have been developed charting changes to the Earth’s climate over time.
This has required an enormous international co-operative effort over many years. It is only on the basis of reliable, irrefutable evidence that decisions of an international significance can take place.
Decisions made now may have far-reaching consequences for the populations of individual countries or continents today, as well as far-reaching global implications for the future.

Question 5

climate change research p2

Answer 5

The need to produce reliable data for issues of this scale is paramount.
Despite the weight of evidence for climate change, some scientists still believe that a causal link between human activity and climate change is yet to be established.
Global warming refers to a rise in the Earth’s mean surface temperature.
The Earth’s climate has shown fluctuations in temperature throughout its history, so it is not possible to say for certain that humans are directly causing global warming.
However, carbon dioxide levels in the atmosphere have significantly increased since the industrial revolution, trapping more thermal energy in the atmosphere.
Therefore most scientists believe that human activities are contributing to global warming.

Question 6

If global warming continues, biodiversity will be affected. For example: p1

Answer 6

The melting of the polar ice caps could lead to the extinction of the few plant and animal species living in these regions.
Some species of animals present in the Arctic are migrating further and further north to find favourable conditions as their habitat shrinks.
Increasing global temperatures would allow temperate plant and animal species to live further north than currently.

Rising sea levels from melting ice caps and the thermal expansion of oceans could flood low-lying land, reducing the available terrestrial habitats.
Saltwater would flow further up rivers, reducing the habitats of freshwater plants and animals living in the river and surrounding areas.

Question 7

If global warming continues, biodiversity will be affected. For example: p2

Answer 7

• Higher temperatures and less rainfall would result in some plant species failing to survive, leading to drought-resistant species (xerophytes, Figure 5) becoming more dominant.
  The loss of non-drought-resistant species of plants would lead to the loss of some animal species dependent on them as a food source.
  These would be replaced by other species that feed on the xerophytes.
• Insect life cycles and populations will change as they adapt to climate change. Insects are key pollinators of many plants, so if the range of an insect changes, it could affect the lives of the plants it leaves behind, causing extinction.
  And as insects carry many plant and animal pathogens, if tropical insects spread, this in turn could lead to the spread of tropical diseases towards the poles.
• If climate change is slow, species may have time to adapt (for example by eating a different food source) or to migrate to new areas.
  This will lead to a loss of native species, but in turn other species may move into the area - so biodiversity would not necessarily be lost.
  The species mix would simply change.

Question 8

Loss of biodiversity in the uk

Answer 8

Scientists have estimated that the present worldwide rate of extinction is between 100 and 1000 times greater than at any other point in evolutionary history.
This is primarily the result of the increase in the world human population.
This has resulted in large areas of land being cleared worldwide, to meet the demand for food.
Twelve to fifteen million hectares of forest are lost worldwide each year - the equivalent of 36 football fields per minute.
These highly diverse habitats are replaced with agricultural land, which has far lower levels of biodiversity.
Conservation agencies have estimated the percentage of various habitats that have been lost in the UK since 1900.
Their findings are summarised in Table 1.

Question 9

Reasons for maintaining biodiversity:

Answer 9

Aesthetic reasons
Economic reasons:
Ecological reasons

Question 10

Aesthetic reasons:

Answer 10

The presence of different plants and animals in our environment enriches our lives. For example, you might like to relax on a beach, walk in your local woodland or park or visit a rainforest.
The natural world provides inspiration for people such as musicians and writers, who in turn provide pleasure for many others through music and books.
Studies have shown that patients recover more rapidly from stress and injury when they are supported by plants and a relatively natural environment.

Question 11

Economic reasons: p1

Answer 11

If biodiversity in an ecosystem is maintained, levels of long-term productivity are higher.
Soil erosion and desertification may occur as a result of deforestation. These reduce a country’s ability to grow crops and feed its people, which can lead to resource- and economic-dependence on other nations.

It is important to conserve all organisms that we use to make things. Non-sustainable removal of resources, such as hardwood timber, will eventually lead to the collapse of industry in an area.
Once all or enough of the raw material has been lost, it does not become economically viable to continue the industry.
Note that even when ‘sustainable’ methods are used - for example replanting forest areas - the new areas will not be as biodiverse as the established habitats they replace.

Large-scale habitat and biodiversity losses mean that species with potential economic importance may become extinct before they are even discovered.
For example, undiscovered species in tropical rainforests may be chemically or medically useful.
A number of marine species use a chemical-based defence mechanism.
These are rich potential sources of new and economically important medicines.

Question 12

Economic reasons: p2

Answer 12

• Continuous monoculture results in soil depletion - a reduction in the diversity of soil nutrients.
  It happens because the crop takes the same nutrients out of the soil year after year and is then harvested, not left for the nutrients to be recycled.
  This depletion of soil nutrients makes the ecosystem more fragile.
  The crops it can support will be weaker, increasing vulnerability to opportunistic insects, plant competitors, and microorganisms.
  The farmer will become increasingly dependent on expensive pesticides, herbicides, and fertilisers in order to maintain productivity.
• High biodiversity provides protection against abiotic stresses (including extreme weather and natural disasters) and disease.
  When biodiversity is not maintained, a change in conditions or a disease can destroy entire crops.
  The Irish potato famine of the 1840s was a direct consequence of the reliance on only two varieties of potato.
  When a new disease spread to the area (the oomycete Phytophthora infestans), neither species contained alleles for genetic resistance, so the entire crop was destroyed.
  This led to widespread famine and the deaths of around 1 million people

Question 13

Economic reasons: p3

Answer 13

Areas rich in biodiversity provide a pleasing, attractive environment that people can enjoy.
Highly biodiverse areas can promote tourism in the region, with its associated economic advantages.

The greater the diversity in an ecosystem, the greater the potential for the manufacture of different products in the future.
These products may be beneficial to humans.
For example, it may make food production more financially viable or provide cures or treatment for disease.

Plant varieties are needed for cross breeding.
which can lead to better characteristics such as disease resistance or increased yield.
The wild relatives of cultivated crop plants provide an invaluable reservoir of genetic material to aid the production of new varieties of crops.
Also, through genetic engineering, scientists aim to use genes from wild plants and animals to make crop plants and animals more efficient, thus reducing the land required to feed more people.
If these wild varieties are lost, the crop plants may themselves also become more vulnerable to extinction.
This is also important ecologically.

Question 14

Ecological reasons p1

Answer 14

All organisms are interdependent on others for their survival.
The removal of one species may have a significant effect on others, for example a food source or a place to live may be lost.
For example, decomposers break down dead plant and animal remains, releasing nutrients into the soil, which plants later use for healthy growth.
Plants rely on bees for pollination - this is important for both wild plant species and commercially produced crops.
Fruit farmers use bees to pollinate their crops; a decrease in the wild bee population would decrease crop yields.

Question 15

Ecological reasons p2

Answer 15

Some species play a key role in maintaining the structure of an ecological community.
These are known as keystone species.
They have a disproportionately large effect on their environment relative to their abundance (in terms of their biomass or productivity).
They affect many other organisms in an ecosystem and help to determine the species richness and evenness in the community.
When a keystone species is removed the habitat is drastically changed. All other species are affected and some may disappear altogether.
It is therefore essential to protect keystone species to maintain biodiversity.

Question 16

Human activity versus biodiversity:

Answer 16

• human activity also plays an important role in increasing biodiversity.
• In many countries, including the UK, the natural habitat is created by human intervention and the management of land.
• For example, farming. grazing, planting of hedges, meadows, and forest management have changed the landscapes, the habitats and the ecology over thousands of years.
• Even the wildest of habitats, such as Dartmoor and the Scottish mountains, are a result of farmers and landowners managing the ecosystems.
• One example is sheep grazing on downlands.
• This enables rare species like the Glanville fritillary (an orange patterned butterfly) to survive.
• By maintaining the grass at low levels it allows the plantains that the caterpillars feed on to thrive and therefore maintains biodiversity.
• research has also shown that after annual controlled burning of gorse and heather in the New Forest (an area of lowland heath), biodiversity soars.
• If left to its own devices, bracken and pioneer tree species such as pine and silver birch would start to dominate.
• Areas of lowland heath worldwide are now rarer than rainforest and provide habitats for rare UK bird and reptile species such as the nightjar and sand lizard.

Question 17

Keystone species:

Answer 17

Sea stars, American alligators and prairie dogs are all examples of key stone species:
Like many keystone species, sea stars are predators.

Alligators make burrows for nesting and to stay warm.

It is estimated that up to 200 species rely on prairie-dog colonies, primarily due to their tunnelling activities.

Question 18

Like many keystone species, sea stars are predators.

Answer 18

They maintain a balanced ecosystem by limiting the population of other species. Sea stars eat mussels and sea urchins, which have no other natural predators.
If the sea star is removed from the ecosystem, the mussels undergo a population explosion, reducing the number of other species present in an area (such as barnacles and limpets) as they compete for space and other resources.
Similarly, if sea urchins are not eaten, their growing population crowds coral reefs, preventing other species from occupying the same area.

Question 19

Alligators make burrows for nesting and to stay warm.

Answer 19

When they abandon their burrow, fresh water fills the space, which is used by other species during the dry season for breeding and drinking.
Alligators are predators, which also contributes to the maintenance of biodiversity in these habitats.

Question 20

It is estimated that up to 200 species rely on prairie-dog colonies, primarily due to their tunnelling activities.

Answer 20

Prairie colonies provide a food source and burrows for other animals such as snakes.
Their tunnelling aerates the soil, which, combined with their droppings, leads to a redistribution of nutrients.
It also channels rainwater into the water table.
These processes help to maintain a biodiverse range of plant life in the region.
So essential is the prairie dog to its habitat that its loss would lead to a change in the ecosystem itself.

Question 21

It is important to maintain biodiversity, but how can this be achieved?

Answer 21

• The obvious way is to stop converting wild land into agricultural or building land.
• However, to cope with population growth this conversion is sometimes unavoidable.
• It is also important that scientists try to repair damage that has already been done, and increase biodiversity.

Question 22

what is Conservation

Answer 22

the preservation and careful management of the environment and of natural resources.
By conserving the natural habitat in an area, organisms’ chances of survival are maintained, allowing them to reproduce.
As a consequence species and genetic diversity can be safeguarded.

Question 23

There are many different ways in which scientists try to conserve biodiversity. They can be divided into two main categories:

Answer 23

in situ conservation - within the natural habitat
ex situ conservation - out of the natural habitat.

Question 24

Scientists are currently trying to conserve a number of species to prevent their extinction.
Species are classified, for the purposes of conservation, according to their abundance in the wild:

Answer 24

extinct
extinct in the wild
endangered
vulnerable

• Non-threatened and categories of least concern follow below.
  Many conservation techniques focus on increasing the numbers of organisms from species that are classified as endangered.
  Scientists also promote the practice of sustainable development - economic development that meets the needs of people today, without limiting the ability of future generations to meet their needs.

Question 25

extinct

Answer 25

no organisms of the species exist anywhere in the world

Question 26

extinct in the wild

Answer 26

organisms of the species only exist in captivity

Question 27

endangered

Answer 27

- a species that is in danger of extinction

Question 28

vulnerable

Answer 28

a species that is considered likely to become endangered in the near future.

Question 29

In situ conservation:

Answer 29

takes place inside an organism's natural habitat. This maintains not only the genetic diversity of species, but also the evolutionary adaptations that enable a species to adapt continually to changing environmental conditions, such as changes in pest populations or climate. By allowing the endangered species to interact with other species, it also preserves the interdependent relationships present in a habitat, therefore interlinked species may also be preserved. In situ conservation is generally cheaper than ex situ conservation. Marine (saltwater), aquatic (freshwater) and terrestrial (land) nature reserves are examples of areas that have been specifically designated for the conservation of wildlife.

Question 30

Wildlife reserves: Once an area has been designated as a wildlife reserve, active management is required. Active management techniques may include: p1

Answer 30

controlled grazing - only allowing livestock to graze a particular area of land for a certain period of time to allow species time to recover, or keeping a controlled number of animals in a habitat to maintain it (see below) restricting human access - for example, not allowing people to visit a beach during the seal reproductive season, or by providing paths which must be followed to prevent plants being trampled controlling poaching - this includes creating defences to prevent access, issuing fines, or more drastic steps such as the removal of rhino horns feeding animals - this technique can help to ensure more organisms survive to reproductive age

Question 31

Wildlife reserves: Once an area has been designated as a wildlife reserve, active management is required. Active management techniques may include: p2

Answer 31

reintroduction of species - adding species to areas that have become locally extinct, or whose numbers have decreased significantly culling or removal of invasive species - an invasive species is an organism that is not native to an area and has negative effects on the economy, environment, or health. These organisms compete with native species for resources halting succession - succession is a natural process in which early colonising species are replaced over time until a stable mature population is achieved. For example, as a result of natural succession any piece of land left alone for long enough in the UK will develop into woodland. The only way to protect some habitats such as heath-, down- or moorland from becoming woodland is through controlled grazing. In different parts of the country ponies, deer, sheep, and cows eat tree seedlings as they appear, preventing succession from heathland to scrubland to woodland. This is an important role played by humans in maintaining some of our most beautiful habitats for future generations.

Question 32

Marine conservation zones:

Answer 32

Marine conservation zones are less well established than terrestrial ones. Lundy Island is currently the only statutory marine reserve in England, but there are many other protected areas. Marine reserves are vital in preserving species-rich areas such as coral reefs, which are being devastated by non-sustainable fishing methods. The purpose of the marine reserve is not to prevent fisherman from visiting the entire area, but to create areas of refuge within which populations can build up and repopulate adjacent areas. Large areas of sea are required for marine reserves as the target species often move large distances, or breed in geographically different areas.

Question 33

Ex situ conservation:

Answer 33

Ex situ conservation involves the removal of organisms from their natural habitat. It is normally used in addition to in situ measures, ensuring the survival of a species.

Question 34

Botanic gardens:

Answer 34

Plant species can be grown successfully in botanic gardens. Here the species are actively managed to provide them with the best resources to grow, such as the provision of soil nutrients, sufficient watering. and the removal or prevention of pests. There are roughly 1500 botanical gardens worldwide holding 35,000 plant species Although this is a significant number (more than 10% of the world's flora), the majority of species are not conserved. Many wild relatives of selectively bred crop species are under-represented amongst the conserved species. These wild species are a potential source of genes, conferring resistance to diseases, pests, and parasites.

Question 35

Seed banks:

Answer 35

A seed bank is an example of a gene bank - a store of genetic material. Seeds are carefully stored so that new plants may be grown in the future. They are dried and stored at temperatures of -20°C to maintain their viability, by slowing down the rate at which they lose their ability to germinate. Almost all temperate seeds, and many tropical seeds, can be stored in this way. Scientists expect that they will remain viable for centuries, providing a back-up against the extinction of wild plants. The Svalbard Doomsday Vault in Norway stores seeds in the permafrost and already houses around 800000 species. It will eventually have 3 million different types of seeds and aims to provide a back-up against the extinction of plants in the wild by storing seeds for future reintroduction and research, for breeding and for genetic engineering in the future. Seed banks don't work for all plants - Some seeds die when dried and frozen, and sadly the seeds of most tropical rainforest trees fall into this category.

Question 36

Captive breeding programmes:

Answer 36

Captive breeding programmes produce offspring of species in a human-controlled environment. These are often run and managed by zoos and aquatic centres. For example, The National Marine Aquarium in South West England is playing an important role in the conservation of sea horse species. Several species are now solely represented by animals in captivity. Scientists working on captive breeding programmes aim to create a stable, healthy population of a species, and then gradually reintroduce the species back into its natural habitat. The Arabian Oryx is an example of a species that was extinct in the wild before its reintroduction.

Question 37

What do Captive breeding programmes provide:

Answer 37

the animals with shelter, an abundant supply of nutritious food, an absence of predators and veterinary treatment. Suitable breeding partners or semen (which can be used to artificially inseminate females) can be imported from other zoos if not available within the zoo's own population. Maintaining genetic diversity within a captive breeding population can be difficult. As only a small number of breeding partners are available, problems related to inbreeding can occur. To overcome this, an international catalogue is maintained, detailing genealogical data on individuals. Mating can thus be arranged to ensure that genetic diversity is maximised. 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 the adults to new locations, and do not require the animals' cooperation.

Question 38

Some organisms born in captivity may not be suitable for release in the wild. These are some of the reasons:

Answer 38

Diseases Behaviour Genetic races Habitat -

Question 39

Diseases

Answer 39

- there may be a loss of resistance to local diseases in captive-bred populations. Also, new diseases might exist in the wild, to which captive animals have yet to develop resistance.

Question 40

Behaviour

Answer 40

some behaviour is innate, but much has to be learned through copying or experience. In an early case of reintroduction, a number of monkeys starved because they had no concept of having to search for food - they had become domesticated. Now food is hidden in cages, rather than just supplied, so that the animals learn to look for it.

Question 41

Genetic races

Answer 41

- the genetic make-up of captive animals can become so different from the original population that the two populations cannot interbreed.

Question 42

Habitat

Answer 42

in many cases the natural habitat must first be restored to allow captive populations to be reintroduced. If only a small suitable habitat exists it is likely that there are already as many individuals as the habitat can support. The introduction of new individuals can lead to stress and tension as individuals fight for limited territory and resources such as food.

Question 43

Conservation agreements

Answer 43

To conserve biodiversity successfully, local, and international cooperation is required to ensure habitats and individual species are preserved. Animals do not respect a country's boundaries. Therefore, to increase the chances of a species' survival, cross-border protections should be offered.

Question 44

International Union for the Conservation of Nature:

Answer 44

Intergovernmental organisations, such as the International Union for the Conservation of Nature (IUCN), assist in securing agreements between nations. At least once a year the IUCN publishes the Red List, detailing the current conservation status of threatened animals. Countries can then work together to conserve these species. The IUCN was also involved in the establishment of the Convention on International Trade in Endangered Species (CITES). This treaty regulates the international trade of wild plant and animal specimens and their products. As the trade in wild animals and plants crosses borders between countries, the effort to regulate it requires international cooperation to safeguard certain species from over-exploitation. Today, more than 35000 species of animals and plants are protected by this treaty.

Question 45

The Rio Convention:

Answer 45

In 1992, an historic meeting of 172 nations was held in Rio de Janeiro, which became known as the Earth Summit. The summit resulted in some new agreements between nations in the Rio Convention: The Convention on Biological Diversity (CBD) requires countries to develop national strategies for sustainable development, thus ensuring the maintenance of biodiversity. The United Nations Framework Convention on Climate Change (UNFCCC) is an agreement between nations to take steps to stabilise greenhouse gas concentrations within the atmosphere. The United Nations Convention to Combat Desertification (UNCCD) aims to prevent the transformation of fertile land into desert and reduce the effects of drought through programmes of international cooperation. Each convention contributes to maintaining biodiversity. They are intrinsically linked, operating in many ecosystems and addressing interdependent issues.

Question 46

Countryside stewardship scheme:

Answer 46

Many conservation schemes are set up at a more local level. An example is the Countryside Stewardship Scheme in England. The scheme, which operated from 1991-2014, offered governmental payments to farmers and other land managers to enhance and conserve the English landscape. Its general aim was to make conservation a part of normal farming and land management practice.

Question 47

Specific aims of the scheme included:

Answer 47

sustaining the beauty and diversity of the landscape improving, extending and creating wildlife habitats restoring neglected land and conserving archaeological and historic features improving opportunities for countryside enjoyment. This scheme has now been replaced by the Environmental Stewardship Scheme, which operates similarly.