Chapter 11- 11.1- Biodiversity Flashcards
What does biodiversity mean?
The variety of living organisms living in an area.
What is the importance of biodiversity?
It is essential in maintaining a balanced ecosystem for all organism. All species are interconnected- they depend on one another.
E.g. Trees provide home for animals.
Animals eat plants, which in turn need fertile soil to grow.
Fungi and other microorganisms help decompose dead plants and animals, returning nutrients to the soil.
In regions of reduced biodiversity these connections may not be there which eventually harms all species in the ecosystem.
We rely on a balanced ecosystem as they provide us with the food, oxygen and other materials we need to survive.
Unfortunately, many human activities, such as farming and clearing land for housing, can lead to a reduction in biodiversity.
How can we measure biodiversity?
Tropical, moist regions (warm all year around) have the most biodiversity.
The UKs temperate climate ( warm summers and cold winters) have less biodiversity.
Very cold areas such as the Artic, or very dry areas such as desserts, have the least biodiversity.
Generally, the closer a region to the equator the greater the biodiversity.
E.g. over 40000 plant species live in the Amazon rainforest, whereas less than 3000 live in Northern Canada.
measuring biodiversity plays an important part in the role of conservation. It informs scientists of the species that are present, thus providing a baseline for the level of biodiversity in an area.
From this information, the effect of any changes to an environment can be measured. These may include the effect of human activity, disease or climate change, for example.
Before a major project is undertaken, such as building a new road or the creation of a new nature reserve, an Environmental Impact Assessment (EIA) is undertaken.
This assessment attempts to predict the positive and negative effects of a project on the biodiversity in that area.
Biodiversity can be studied at different levels:
- Habitat biodiversity
- Species biodiversity
- Genetic biodiversity
What is habitat biodiversity?
Tis refers to the number of different habitats found within an area. Each habitat can support a number of different species. Therefore in general, the greater the habitat biodiversity, the greater the species biodiversity will be within that area.
The UK is home to a large number of habitat types, including meadow, woodland, streams, and sand dunes.
It has a large habitat biodiversity. By contrast Antarctica, covered almost entirely by an ice sheet, has a very low habitat biodiversity and very few species live in this region.
On a smaller scale, countryside that is habitat rich, perhaps with a river, woodlands, hedgerows and wild grasslands, will be more species rich than farmed countryside with large ploughed fields making up a single habitat.
What is species biodiversity?
2 different components:
- Species richness - the number of different species living in a particular areas, and
- Species evenness - a comparison of the numbers of individuals of each species living in a community. (The community is all the populations of living organisms in a particular habitat).
Therefore an area can differ in its species biodiversity even if it has the same number of species. E.g. A cornfield and a grass meadow make up 95% of the community with the remaining 5% made up of other organisms including weed plants, insects, mice, and birds.
In the grass meadow the species will be more balanced in their populations.
What is genetic biodiversity?
It refers to a variety of genes that make up a species. Humans have about 25000 genes, but some species of flowering plants have as many as 400000 genes.
Many of these genes are the same for all individuals within the a species. However, for many genes, different versions (alleles) exist.
This leads to genetic biodiversity within a species.
Genetic biodiversity within a species can lead to quite different characteristics being exhibited. E.g. Some genes are the same for all breeds of dog- these genes define the organism as a dog. Some of the genes have many alleles- they code for the wide variation in characteristics seen between different breeds of dog, for example coat colour and length.
Greater biodiversity within a species allows for better adaptations to a changing environment, and is more likely to result in individuals who are resistant to disease.
