Biodiversity refers to the variety of life. It is seen in the number of species in an ecosystem or on the entire Earth. Biodiversitygets used as a measure of the health of biological systems, and to see if there is a danger that too many species become extinct.
Biologists most often define biodiversity as the "totality of genes, species, and ecosystems of a region". An advantage of this definition is that it seems to describe most circumstances. There are three levels at which biological variety can been identified:
- species diversity
- ecosystem diversity
- genetic diversity
Ecosystem or ecological diversity
There is a large variety of different ecosystems on earth, which have their own complement of distinctive inter linked species based on the differences in the habitat. Ecosystem diversity can be described for a specific geographical region, or a political entity such as a country, a state or a taluka. Distinctive ecosystems include landscapes such as forest, grasslands, deserts, mountains as well as ecosystems such as rivers, lakes and the sea. Ecosystems are most natural in wilderness areas. If natural ecosystems are overused or misused, their productivity eventually decreases and they are then said to be degraded. Ecosystem diversity is often evaluated through measures of the diversity of the component species. This may involve assessment of the relative abundance of different species as well as consideration of the types of species. Weight is given to the numbers of species in different size classes, at different trophic levels, or in different taxonomic groups. Thus a hypothetical ecosystem consisting only of several plant species would be less diverse than one with the same number of species but that included animal herbivores and predators.
- Species diversity
Species is a basic unit of classification and is defined as a group of similar organisms that mate and produce offspring’s with one another and thus, share a common lineage. The number of species of plants and animals that are present in a region constitutes its species diversity. This diversity is seen both in natural ecosystem and in agricultural ecosystems. Some areas are richer in species than others.
- Genetic diversity
Genetic diversity is reliant on the heritable variation within and between populations of organisms. New genetic variation arises in individuals by gene and chromosome mutations, and in organisms with sexual reproduction it can be spread through the population by recombination. It has been estimated that in humans and fruit flies alike, the number of possible combinations of different forms of each gene sequence exceeds the number of atoms in the universe. Other kinds of genetic diversity can be identified at all levels of organization, including the amount of DNA per cell and chromosome structure and number. Selection acts on this pool of genetic variation present within an interbreeding population. Differential survival results in changes of the frequency of genes within this pool, and this are equivalent to population evolution. Genetic variation enables both natural evolutionary change and artificial selective breeding to occur. Only a small fraction of the genetic material of higher organisms is outwardly expressed in the form and function of the organism; the purpose of the remaining DNA and the significance of any variation within it are unclear. Each of the estimated 109 different genes distributed across the world’s biota does not make an identical contribution to overall genetic diversity.
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Why Is Biodiversity Important? Who Cares?
Why is Biodiversity important? Does it really matter if there aren’t so many species?
Biodiversity boosts ecosystem productivity where each species, no matter how small, all have an important role to play.
For example, a larger number of plant species means a greater variety of crops; greater species diversity ensures natural sustainability for all life forms; and healthy ecosystems can better withstand and recover from a variety of disasters.
And so, while we dominate this planet, we still need to preserve the diversity in wildlife.
Loss Of Biodiversity And Extinction
It has long been feared that human activity is causing massive extinctions. Despite increased efforts at conservation, it has not been enough and biodiversity losses continue. The costs associated with deteriorating or vanishing ecosystems will be high. However, sustainable development and consumption would help avert ecological problems.
Climate Change And Global Warming
The climate is changing. The earth is warming up, and there is now overwhelming scientific consensus that it is happening, and human-induced. With global warming on the increase and species and their habitats on the decrease, chances for ecosystems to adapt naturally are diminishing. Many are agreed that climate change may be one of the greatest threats facing the planet. Recent years show increasing temperatures in various regions, and/or increasing extremities in weather patterns.
This section explores some of the effects of climate change. It also attempts to provide insights into what governments, companies, international institutions, and other organizations are attempting to do about this issue, as well as the challenges they face. Some of the major conferences in recent years are also discussed.