Biodiversity
Biodiversity: Definition and Importance
- Biodiversity is the term used to describe the variety of life on Earth - it encompasses the diversity within species, between species, and the diversity of ecosystems.
- It’s a key aspect of the planet’s health - greater biodiversity implies a greater resilience of ecosystems to changes or shocks.
- Biodiversity has important economic benefits; it provides ecosystem services including pollination, soil fertility, and medicinal resources.
Species and Genetic Diversity
- Species diversity refers to the range of different species in a community. Species richness (number of species) and species evenness (distribution of individuals among species) contribute to species diversity.
- Genetic diversity within a species is the total number of different alleles in the population - the more diverse, the better the chance of survival. This can increase through gene mutations and sexual reproduction.
Measuring Biodiversity
- Biodiversity can be measured using simpson’s diversity index (SDI), which takes into account the number of species and their relative abundance - high SDI values indicate high diversity.
- Another approach is the shannon-wiener index (SWI), however, the interpretation of values is less straightforward than SDI.
Factors affecting Biodiversity
- Habitat destruction and climate change impact biodiversity - loss of habitat can lead to species extinction, thus reducing biodiversity.
- Invasive species can outcompete native species for resources leading to a decrease in species diversity.
Conservation of Biodiversity and Legislation
- Conservation efforts, including the creation of nature reserves, can help protect species and preserve biodiversity.
- Legislation, like the CITES agreement and EU Habitats Directive, contribute to creating and maintaining protective measures for species at risk.
Biodiversity and Evolution
- Biodiversity is a result of evolution, the process of gradual development of organisms from preexisting forms.
- Changes in environmental conditions can lead to natural selection, in which the most suited organisms within a species survive and reproduce.
- Over time, this selection can lead to a rise in the prevalence of advantageous traits, leading to speciation, and thus increasing biodiversity.