7/29/2019 FY Lecture Notes Biodiversity

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FY Lecture Notes 21/12/12 [Type text]

Biodiversity

- Biodiversity is the variety and differences among living organisms from all sources, including terrestrial,marine, and other aquatic ecosystems and the ecological complexes of which they are a part. It isvirtually synonymous with Life on earth.

- Biologists most often define "biological diversity" or "biodiversity" as the "totality of genes, species, andecosystems of a region. The biodiversity found on Earth today consists of many millions of distinctbiological species, which is the product of nearly 3.5 billion years of evolution.

- Biological diversity or biodiversity is the term given to the variety of life on Earth and the natural patternsit forms.

- The variety and variability of life-forms, both contemporary and extinct, including genetic and ecosystemdiversity, in a defined area at and over time Biological diversity is a measure of the diversity of all life at

all levels of organization.- Biodiversity is All of the hereditary variation in organisms, from differences in ecosystems to the species

composing each ecosystem, thence to the genetic variation in each of the species. As a term,biodiversity may be used to refer to the variety of life of all of Earth or to any part of it.

Types of Biodiversity

Species diversity All the species on Earth, from single-celled bacteria and protists to the multicellularkingdoms (plants, fungi, and animals). Species diversity is an index that incorporates the number ofspecies in an area and also their relative abundance.

Genetic diversity -The genetic variation within species, both among geographically separatepopulations and among individuals within single populations. In other words It is a levelof biodiversity that refers to the total number of genetic characteristics in the genetic makeup of aspecies.

Ecosystem diversity- The different biological communities and their associations with the chemical andphysical environment (the ecosystem). Ecosystem diversity refers to the diversity of a place at the levelof ecosystems.

7/29/2019 FY Lecture Notes Biodiversity

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FY Lecture Notes 21/12/12 [Type text]

Biodiversity can also be classified as

Structural diversity -genetic structure, physiognomy, landscape patterns

Functional diversity ecological and evolutionary processes (e.g., photosynthesis, biogeochemicalcycling, predation, parasitism, life history, etc.)

Compositional diversitygenes, species, ecosystems

Values of Biodiv ersity:

Food: About 80,000 edible plants and about 90% of present day food crops have been domesticatedfrom wild.

Drugs & Medicines:About 75% of worlds population depend on plants or plant extracts.

Fuel: Forests have been used since ages for fuel wood. Fossil fuels are also products of Biodiversity.

Social Value: Many of the plants like Tulsi, Lotus, Peepal etc are considered holy and sacred.

Species

- The bio logical species conceptThe biological species conceptdefines species in terms of interbreeding. Mayr (1963), for instance defined aspecies as follows: species are groups of interbreeding natural populations that are reproductively isolatedfrom other such groups. The expression reproductively isolated means that members of the species do notinterbreed with members of other species, because they have some attributes that prevent interbreeding.

- The ecolog ical species conceptEcological species can be defined as a set of organisms who exploit a certain set of niches, where the setincludes the niches exploited by different life stages, genders, or other forms within the species.)

- Typological, morphological speciesSpecies can be described according to morphology. According to this species are set of organism who looksimilar.

- Cladistic species conceptA species is a monophyletic group (a group including all descendents of an ancestor).