Biology: Unit F212: Molecules, Biodiversity, Food and Health
Humans, Conservation and the Future
There are 6 main reasons why it is important that steps are taken to preserve biodiversity:
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Ethical reasons: all living organisms have the right to survive and to live in the way for
which they have become adapted.
Aesthetic reasons: people enjoy observing the infinite variations of nature. Studies show
that patients recover more rapidly from stress and injury when exposed to natural
environmental conditions – clearly demonstrating that natural ecosystems are
important for out physical, intellectual and emotional health.
Agriculture. The increase in intensive farming has meant that selective
breeding programmes have eliminated many alleles from farmed populations.
The narrower the gene pool, the more likely it is that all will be susceptible to
a certain disease, or all unable to cope with a certain environmental
condition. If climate changes, we will need a variety of alleles in the gene pool,
so that there is a hope of having one species which is able to survive.
Economic reasons: evolution has provided answers to many technological problems that
we face; like the best aerodynamic shape in water and the best shape for an aerofoil or
wing. If these species are allowed to go extinct, we could be losing solutions to new
problems.
Ecological reasons include: Natural ecosystems perform processes that are valuable to
humans, like the growth of timber, food and fuel, formation and fertilisation of soil and
recycling of nutrients.
Biodiversity is also important for the creation of new medicines; research
chemists often look to the natural environment for treatments and cures. For
example, Digitalin, found in the foxglove, is a drug used to treat heart
conditions. The more species that are conserved, the better the chance is that
cures for other diseases will be able to be found.
Climate change could alter several environmental factors which will in
turn affect agriculture. Higher carbon dioxide levels may increase rate of
photosynthesis; higher temperatures may lead to increased growth rates;
longer growing seasons; all of these factors may be beneficial to
agriculture. However, a rise in sea levels may cause loss of land; salinity of
soil may increase; rainfall may be unreliable; desertification may set in, in
parts of Southern Europe.
Climate change will affect the spread of disease. New pests and diseases in plants
which can survive in different areas due to the climatic changes will kill crops which
have no specific resistance. Human diseases will also be affected; tropical diseases
which thrive in the warmth and moisture of the Tropics may become a problem in
Europe. The female anopheles mosquito which carries malaria may be able to
survive further North, spreading the disease to new areas.
Benefits to agriculture of maintaining biodiversity: There are many advantages for
agriculture of the maintaining of biodiversity. A larger gene pool provides genetic material
which could potentially develop improved varieties and yields. We may be able to use wild
species to introduce new alleles helping to produce varieties and breeds that are more
suited to new requirements in the future.
Conservation In Situ means conserving a species in its normal environment. It is possible to
pass legislation which stops logging and hunting. In situ conservation could take place by
making areas conservation parks. Designating an area as a reserve means that plants and
animals are conserved in their natural environment, and biodiversity is permanently
protected. It also protects significant elements of cultural and natural heritage.
Advantages: It attempts to minimise human impact on the natural environment and
protecting the natural environment. Some governments will not pass legislation to ban
hunting, and such legislation can be difficult to enforce. In situ conservation facilitates
scientific research and allows close management of the ecological integrity of an area.
Disadvantages: Protected animals may leave the reserve and raid crops of nearby
populations. Tourists who visit the reserves may leave litter and disrupt the lives of local
indigenous people.
Conservation Ex Situ means conserving a species by activities which take place outside its
normal environment. Zoos play a part in the conservation of animal species; they
concentrate on breeding endangered species, and such breeding programs can
increase the number of individuals in the species. They can also enable
repopulation by introducing captive bred animals to the wild. In the captive
environment, animals are protected from predators and their health can be
maintained by veterinary science. Modern techniques make it possible to
preserve large amounts of genetic material by freezing sperm or eggs. Artificial
insemination, in vitro fertilisation and embryo transfer techniques can be used with wild
animals in breeding programs. Plants can often be grown asexually.
Advantages: Conserves endangered species.
Increase population numbers so species no longer threatened by extinction
Disadvantages: Difficult to move organisms without harm
Hard to recreate their natural environment
Evolutionary development is halted, so when released back into wild, the creature may lack
the adaptations it needs to survive in the ever changing natural environment.
Plant species are conserved ex situ by botanical gardens. Seeds are collected from the wild
population and then stored and germinated in protected environments. This allows the
botanical garden to individual numbers within species quickly. Captive bred individuals can
be replanted in the wild. However; there are disadvantages. Collection of seeds from wild
plants may cause disturbance. Those collected may not hold a representative sample of
genetic diversity, and so the offspring may not grow successfully in a different area. Seed
banks are collections of seed samples. The Kew Millennium Seed Bank Project in Sussex is
one such project. It aims to store a representative sample of seeds from every known
species of plant, including the rarest, most useful and most threatened species. The seeds
can be used for foods in rural communities or disease resistant crops for agriculture. The
seeds are stored in very dry or freezing conditions in order to prolong their viability. At Kew,
10,000 germination tests are carried out every year. This involves planting the seeds on
nutrient agar and measuring the germination rate. It is hoped that this will lead to the
development of the most effective method of storage.
The Convention on International Trade in Endangered Species of wild flora and fauna
(CITES) is an international agreement, first made in 1973, by the majority of world
governments. Its aim is to ensure that the international trade in wild animals does not
threaten their survival. CITES has 3 categories: appendix I lists the species that are
considered to be the most endangered, and all international trade in them or any products
that come from them is prohibited; appendix II lists the animals which are not necessarily
threatened with extinction now, but may become so unless trade is closely controlled, and in
this case, CITES allows trade if an export permit is granted by the country from which the
organism is taken. Appendix III includes species where there is a regulated international
trade, and CITES requires that permits are held in order to import or export these species.
In 1992, the Rio de Janeiro Earth Summit took place. At this meeting, over 170 countries
agreed on the need to work together in global partnership for sustainable development.
Agenda 21 was set out – a global action plan to
reduce the impact of development on our future. 10
years later, in 2002, the Johannesburg Summit
brought together the world’s governments, industries
and scientific authorities to make a commitment to
the reduction of the rate of biodiversity loss. The
International Union for the Conservation of nature
and natural resources annually publishes a red list of
threatened species. This system is designed to
determine the relative risk of extinction, and the main purpose of the IUCN Red List is to
catalogue and highlight those plants and animals that are facing a higher risk of global
extinction. There is a higher proportion of vertebrates compared to invertebrates, and no
prokaryotes, as it is unknown as to how many of these are threatened.
Environmental impact assessments are carried out by local authorities before any major
development. The developer must firstly assess the local biodiversity and identify any effects
of the development. The local planning authority will consider the size of the development,
its likely impacts, and the environmental sensitivity of the area before making its decision to
approve the development.