Have you ever noticed the diversity around you? What role do they play in the biosphere? And what is their importance? Our biosphere is full of diversities. The variety of animals, plants, fungi, and even microorganisms like bacteria are responsible for making our natural world. Each species and organisms work together in ecosystems to maintain the balance and support life. Biodiversity supports everything in nature that you need to survive.
According to the CBSE marking scheme of the Class 12 Term 2 Biology board exam, Unit- Ecology and Environment consists of 12 marks in total. Students can gain this perfect score as this unit is the easiest to revise in a short time compared to others. In this article, let us have a quick revision on the Biodiversity and Conservation chapter for Class 12 Term 2 board exam preparations.
All the different kinds of life you can find in one area are known as Biodiversity. There are various types of diversities in nature. They are a precious wealth of nature that needs to be conserved. In recent centuries, due to human activities, we have lost millions of species, and many species reached the level of extinction. And it takes millions of years to accumulate this rich diversity in nature. Therefore, it is necessary to conserve them.
Types of Biodiversity
The term ‘biodiversity’ was popularised by the socio-biologist Edward Wilson. Some important biodiversities are-
- Genetic Diversity
A single species might show high diversity at the genetic level over its distributional range. For example, the genetic variation of the medicinal plant Rauwolfia vomitoria.
- Species Diversity
It is the diversity at the species level. For example, the Western Ghats or the Eastern Ghats in India.
- Ecological Diversity
It is the diversity at the ecosystem level. For example- deserts, rainforests, etc.
Number of Species on Earth And in India
- There are more than 1.5 million plants and animal species recorded globally. Nearly 45,000 plants and more than twice as many animals are recorded in India.
- More than 70% of all species recorded are animals, while 30% are plant species.
- The number of fungi species recorded in the world is more than the combined total of the species of fishes, amphibians, reptiles, and mammals.
- India is one of the twelve mega biodiversity countries of the world. It has only 2.4% of the world’s land area and 8.1% of the global species biodiversity.
Pattern of Biodiversities
So far from the records, Biodiversity has shown two types of patterns:
- Latitudinal gradients
The plants and animals are unevenly distributed throughout the world. This distribution pattern is along the latitudinal gradient in diversity in the world. The species diversity is more in tropical regions than in temperate or polar areas. It is because tropical regions have a long evolutionary time for species diversification, various seasonal environments, and the availability of more solar energy.
- Species – Area relationships
Alexander Von Humboldt observed that species richness gets increased within a region when an explored area is increased, but only up to a limit. A straight line was obtained when the relationship between species richness and area was drawn using a logarithmic scale. And the equation is written as
log S = log C + Z log A
Where S= species
Z= slope of the line
Importance of Species Diversity To The Ecosystem
The number of species directly affects the ecosystem of that area. More the species, the more stable the area is compared to those with fewer species. A stable community should not show too much variation in productivity from year to year. It is considered that rich biodiversity is essential for ecosystem health and imperative for the very survival of the human race on this planet. It is observed that the plots with more species showed less year-to-year variation in total biomass, and increased diversity contributed to higher productivity.
Loss of Biodiversity
The presence of various species on the Earth is a precious biological wealth. And human activities are the biggest reason for the continuous loss of this wealth. Loss of biodiversity in a region leads to a decline in plant production, an increase in drought, flood, environmental problems, and increased water use, disease, productivity, etc.
The IUCN Red List (2004) documents enlist the extinction of 784 species (including 338 vertebrates, 359 invertebrates, and 87 plants) in the last 500 years. Some examples of recent extinctions include the dodo (Mauritius), quagga (Africa), thylacine (Australia), Steller’s Sea Cow (Russia), and three subspecies (Bali, Javan, Caspian) of the tiger. in the last 20 years, 27 species have been disappeared.
Need For Conserving Biodiversity
There are many reasons for conserving biodiversity, and broadly they are classified under three categories:
- Narrowly Utilitarian
Humans obtain countless direct economic benefits from nature like food, firewood, fibres, construction material, medicinal plants, and industrial products. And more such resources result in enormous benefits.
- Broadly Utilitarian
Biodiversity plays a major role in the ecosystem services that nature provides. Production of oxygen by trees, pollination of flowers leads to the growth of trees, and delight in using nature’s benefits are priceless treasures.
The ethical argument for conserving biodiversity relates to what we owe to millions of plant, animal, and microbe species with whom we share this planet. Our moral duty is to care for this treasure and pass on our biological legacy in good order to future generations.
Ways To Conserve Biodiversity
We can conserve biodiversity in two ways-
- In-situ ( on-site) conservation
Protecting biodiversity at all levels by conserving and protecting the whole ecosystem is called in situ conservation. In this conservation process, species are conserved and protected in their natural habitat. Biosphere reserves, national parks, wildlife sanctuaries, hotspots, wild forests, etc., are included under In-situ conservation. There are 34 biodiversity hotspots in the world. India has 14 biosphere reserves, 90 national parks, and 448 wildlife sanctuaries.
- Ex-situ (off-site) conservation
The process in which endangered and threatened animals are saved by taking urgent measures is called Ex-situ conservation. In this method, threatened animals and plants are taken out from their natural habitat and placed in special settings where they are protected and given special care. Zoological parks, botanical gardens, wildlife safari, aquariums, gene banks, etc., are included under Ex-situ conservation.
It is a serious issue that we are losing our biological wealth at a rate visible to naked eyes. If this continues for a long time, then one day, our future generation will not be able to see this beauty of nature on our Earth. And we will be responsible for this.
We hope that this article can help all Biology students of Class 12 with a quick revision on the Biodiversity topic. You can take help from NCERT Solutions for the Class 12 Biology book for more information.