Conservation & Preservation (OCR A Level Biology): Revision Note

Conservation & Preservation

• Humans have been successful in colonising every continent and many harsh habitats

• As a result, the human population has grown and is still in its logarithmic growth phase

The increase in world population over time

• In order to avoid outcompeting many species and forcing such species into extinction, humans have to adopt the role of environmental custodian. This places a responsibility on humans to manage habitats and species in a way that ensures sustainability and biodiversity for the good of future generations

• The ecological techniques that have been used are conservation and preservation which have things in common but are subtly different

Conservation

• Maintaining biodiversity and sustainability

• By allowing changes to the profile of organisms in an ecosystem

• Allowing human activity alongside other species in a managed way

Preservation

• Maintaining habitats and populations exactly as they are now

• Making no allowance for usage by humans

• This takes place in small geographical areas with little or no human population but allows no human intervention eg. areas of Arctic tundra where mineral mining has been prohibited

• Humans' efforts to maintain a sustainable biosphere have focused on conservation rather than preservation

Reasons for conserving biological resources

• There are many reasons for conserving biodiversity and all the resources that are associated with it, such as:

  • People believe that humans have a moral obligation to prevent the manmade loss of biodiversity

  • The supply of important natural resources such as wood for construction and paper

  • Employment

  • The supply of food for the human population

  • Economic benefits to individual countries

  • As humans are the most intelligent species on the planet the responsibility falls upon their shoulders to protect and value all of the organisms on the planet

Ecological reasons

• Biodiversity has a major effect on the stability of an ecosystem

  • A more diverse ecosystem is better able to survive and adapt to environmental changes or threats

• For example, if the temperature of a species-rich lake rises due to global warming:

  • Some species of fish in the ecosystem are unable to cope with the change while others can

  • The fish that are able to cope will survive, reproduce and keep contributing to the ecosystem

• Within communities there are keystone species that have a larger impact on the ecosystem than others

  • When these species are lost there are several knock-on effects

  • Bush elephants in the African savannah are a keystone species

    • They graze in a very extreme way, knocking over and eating several species of tree

    • This destruction of vegetation actually helps to maintain the ecosystem

    • Elephant dung also provides a habitat for many important fungi and insect species

    • When elephants were hunted legally for their ivory, their numbers reduced and scientists observed a major negative impact on the savannah

Environmental reasons

• Humans need diverse ecosystems because of the essential environmental services they provide

• Plants absorb carbon dioxide from the atmosphere and help to reduce the greenhouse effect and climate change

• Microorganisms digest and break down the masses of organic waste that are produced by larger organisms

• Humans have irrigation and drinking water thanks to the transpiration of plants and their contribution to the water cycle

• Different fungi and bacteria species are a major part of the nutrient cycle that allows for nutrients to reenter the soil for further plant growth

• Plants are producers in food webs. They are both a direct and indirect energy source for humans through fruit, vegetables and meat

Economic reasons

• Ecosystems have a lot of economic value

• Many of the medicines used today have originated from plants, fungi and bacteria

  • For example the cancer-fighting drug paclitaxel is sourced from Pacific and Himalayan Yew Trees

  • The Himalayan Yew has declined in numbers due to over-harvesting for fuel and medicine

  • Due to the large number of drugs that have already been sourced from nature it is reasonable to assume that there are other drugs, yet to be found in nature, that could be used in the future

• Ecotourism a major source of income for many countries

  • Many tourists travel to and spend money in National parks so they can see wildlife

  • Increased tourism in a country contributes to the economy and provides jobs

• Ecosystems have also made major contributions to the field of science and technology

  • The specific enzyme used in DNA sequencing was first discovered in thermophilic bacterium found in a hot spring in Yellowstone National Park, USA

Aesthetic reasons

• Humans find great joy and pleasure in the beauty of nature

• It provides inspiration for creatives such as photographers, poets, musicians and artists

• There is a strong argument for preserving biodiversity because of its aesthetic benefits

Ethical reasons

• Many people believe that humans have a moral obligation to prevent the loss of biodiversity that results from human activities

• Humans share the planet with millions of others species and they have no right to cause the extinction of other species

• As humans are the most intelligent species on the planet the responsibility falls upon their shoulders to protect and value all of the organisms on the planet

Social reasons

• Many people enjoy spending time in the natural environment

• There are many activities that people can do together in nature, e.g. birdwatching, walking, climbing

• Such environments may be lost if they are not conserved, with the loss of the social benefits that they can bring