• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

The Benefits of Biodiversity And Threats To It.

Extracts from this document...


________________ ________________ ________________ 2. Biodiversity is the variety of species on earth; extinction is the loss of species. Many new causes of extinction and lack of biodiversity have arisen which are directly attributable to human influences such as use of resources. ________________ ________________ ________________ ________________ 3. Reasons for species becoming endangered or extinct include: natural selection; habitat destruction such as deforestation and loss of hedgerows; pollution such as PCBs and oil; hunting and collecting; competition from domestic animals. ________________ ________________ ________________ Biodiversity is the variety of species on the earth. [Or if you prefer: Biodiversity is a contraction of ?biological diversity? and refers to the number, variety and variability of living organisms. It embraces two different concepts: one is a measure of how many different living things there are and the other is the measure of how different they are.] The benefits of biodiversity are: 1. ...read more.


Marine life has also been affected. About one third of the planet?s marine fish species rely on coral reefs. At the current rate of destruction, about half of the reefs could easily be lost in the next 20 years. About half the world?s forests have been cut down by deforestation during the last 30 years for reasons such as: the world demand for timber; wood can be used as a fuel; land is needed for farming; new roads; demand for paper and packaging. As well as the reduction in biodiversity caused by the loss of habitats, forests help to maintain a balance of carbon dioxide and oxygen in the atmosphere. Introduction of exotic species and competition from domestic animals Many exotic species are accidentally introduced, such as certain weeds and insect pests. Others are deliberate. For example, foxes, rabbits and cats were taken to Australia aboard European ships and have since ruined Australia?s indigenous wildlife. ...read more.


Their use has been banned or severely restricted in many countries since the 1970s and 80s because of the possible risks to human health and the environment. An oil spill is the release of a liquid petroleum hydrocarbon into the environment due to human activity, and is a form of pollution. Oil spills affect marine life by physical contamination or by smothering or by the bioaccumulation of the toxic components of oil in animal and plant tissues. Natural Selection The organisms that are better adapted to their environment are more likely to survive and reproduce offspring that are successful. There is a struggle for survival (competition between animals of the same species), with only those with the best genetic advantages surviving. These individuals reproduce and pass on their successful characteristics to their offspring, giving the next generation a selective advantage. When the environment or conditions change, the features needed to survive in it changes, so natural selection is continuous process. Natural selection can also maintain variation if there is no need to change and therefore stabilises a population. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Living Things in their Environment section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Living Things in their Environment essays

  1. Why Do Penguins Huddle

    Each experiment shall be repeated three times, and the average of each try recorded. It is also important to note the safety considerations of this procedure. The water temperature (50 degrees) can do no harm to a person, and does not burn or hurt when you touch it.

  2. Grizzly Bears

    If they did, there would be much fewer left. Though they do roam free in the scraps of wilderness they have left. Grizzlies are both predator and prey. They are predators to squirrels, fish, caribou, wolves, Dall sheep, moose, and other small animals. They are prey to moose, caribou, and larger animals.


    3 45�C 43�C 40�C 38�C 37�C 35�C 34�C 34�C 32�C 32�C 31�C 4 47�C 45�C 40�C 38�C 37�C 34�C

  2. Palau Coral Reef.

    meters (300 feet), but reef-building corals grow poorly below 18-27 meters (60 to 90 feet). Corals also grow poorly near river openings or coastal areas with excessive run-off, because corals need salt water to survive. Coral reefs occupy less than one quarter of one percent of the earth's marine environment,

  1. Human Impact on Nutrient Cycling.

    A very indirect human impact on a nutrient cycle is acid rain, caused by pollution from power plants factories. The acidic rain falling on naturally acidic soils reduces the pH so much as to cause aluminium and iron to become soluble and subsequently toxic to the trees.

  2. Rain forests.

    plants that can grow in dim light. Many popular house plants, such as philodendrons, dieffenbachia, and ferns, are developed from species that live in this area. Some scientists believe only 1 percent of the sunlight available to emergent trees reaches the understory.

  1. The effect of succession on diversity in heather moorland.

    Diagram left: plants form clusters within a population. Random sampling may coincide with the clusters to produce misrepresentative results. Analysis of results This section describes how I will handle and analyse the results. Recording TABLE FOR MY RESULTS The codes for the table are as follows: * * Ecological Stage

  2. The comparison of bacterial content in a range of milks.

    In such cases, the function of the medium also will determine its composition. There are a number of different methods that could be used: The spread plate and streak plate: " If a mixture of cells is spread out on an agar surface so the every cell grows into a

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work