Biodiversity and Conservation Notes Class 12 Chapter 13

CBSE Class 12 Science Notes Chapter 13 Biodiversity and Conservation are an important part of Class 12 Science Notes for quick revision. They will benefit from having challenging study material to use in preparing for the exam. Students can get CBSE Class 12th Science Notes Chapter 13 Biodiversity and Conservation, Biodiversity, Types of Biodiversity, Importance of Biodiversity, How Many Species on Earth and How Many Species in India, Causes and Reasons for Biodiversity under this chapter We protect biodiversity. This CBSE Class 10 Science Chapter Questions and Answers for Biodiversity and Conservation is helpful to remember well.

Biodiversity

The term “biodiversity” describes the abundance and diversity of life on Earth. Biodiversity is one of the most complex and unique features of our world. Life cannot survive without biodiversity. The word  “biodiversity”   was first founded in the year 1985. The scientist Edward Wilson explained biodiversity as the combined diversity at all levels of biological organization”. It is necessary for natural as well as artificial ecosystems because both depend on biodiversity. The Biosphere, a diverse feature of nature, is covered. This includes variability among plants, animals, and microorganism species. Biodiversity includes the variety of different organisms and their relative frequencies in an ecosystem. It also depicts the organization of organisms at various levels.

Biodiversity maintains ecological and economic importance. It provides us with nourishment, housing, fuel, clothing, and several other things., It also extracts financial advantages via tourism. Therefore, it is necessary to have an excellent knowledge of biodiversity for sustainable livelihood.

There are three types of biodiversity are present  that are mentioned Below:

• Genetic Biodiversity
• Species Biodiversity
• Ecological Biodiversity

Genetic Biodiversity

“A single species may exhibit high genetic biodiversity over its distributional range”.It refers to the differences between the genetic resources of the organisms. Every Member of a specific species differs from each other in their genetic constitution. As a result,  every person has a unique appearance. Similarly, there are various varieties of single species of rice, wheat, maize, barley, and all other crops. More than 50,000 genetically distinct strains of rice and 1,000 distinct mango kinds can be found in India

Species diversity 

Species diversity is referred to as the variety of various types of species present in a specific Region. It represents biodiversity at its most fundamental level. It includes all the species ranging from plants to various microorganisms. No two individuals of the same species differ slightly from one another. For Instance, humans exhibit a lot of biodiversity within themselves. 

Ecological Biodiversity

An ecosystem is a group of living and non-living organisms that are connected to each other. Ecological biodiversity referred to the variations in the plant and animal species that stay together and are associated with food chains and food webs.

Importance of Biodiversity

Biodiversity and its maintenance are crucial for sustaining life on Earth. Several of the reasons explaining the significance of biodiversity are:

• Ecological Stability: Each Species plays a specific function in an ecosystem. They collect and store energy and also developed and break down organic matter. The ecosystem helps to services without which people cannot survive. A diverse ecosystem is more developed and more resilient to environmental stress.
• Economic Importance: Biodiversity is a storehouse of many things for the manufacture of food, cosmetic development, and pharmaceuticals.
• Ethical Importance: All species have the right to be every species. People should not become the cause of their voluntary extinction. Diverse cultures and spiritual heritage are protected by biodiversity. Therefore, it is specific to the conservation of biodiversity.

How Many Species Are There On Earth And How Many In India

It is a fundamental feature of life in our world Since it provides us with essential ecosystem services, including food, medicine, and natural resources. As per the IUCN (International Union for Conservation of Nature), there are around 8.7 million species on Earth, but only 1.2 million of these species have been scientifically described and Classified. Of these 1.2 million species that have been described, approximately 41,000 are considered threatened with extinction.

The approximate number of species in each group according to species classification is as follows:

• Invertebrates: It includes around 7.5 million species of invertebrates are estimated to exist on Earth, involving insects, mollusks, and sponges.
• Vertebrates: It includes approximately 66,000 species of vertebrates, including mammals, birds, reptiles, amphibians, and fish.
• Plants: There are approximately 300,000 species of plants, involving flowering plants, ferns, mosses, and gymnosperms.

Pattern of Biodiversity

Different types of patterns of biodiversity are:

Latitudinal Gradient

The latitudinal gradient pattern is the most easily understood and well-known method to study biodiversity. As per this pattern, the specie’s biodiversity follows a predictable Pattern as we proceed from the equator to the polar areas. The biodiversity of plants and animals is highest at the equator and decreases as we proceed toward the poles. There may be exceptions for a few species, but overall, this is a usually observed trend. Ecologists suggest the following as the cause of the increased biodiversity in the tropics:

• Tropical regions have a more consistent climate compared to that of temperate regions. When the species do not require to constantly adapt to a changing season, the tropics are able to maintain a higher variety of species.
• The temperate zone has suffered several avalanches in the recent past, as a result of which they have a very unstable ecosystem. Whereas, the tropics have been relatively stable. As a result, specialization has occurred more frequently in tropical regions than in temperate regions.
• The tropical regions are compared to other regions more susceptible to solar energy. Thus, plants in this zone obtain more energy during the photosynthesis process. As a result, later trophic levels in the food chain receive more energy. Thus, more energy helps in more diversity.

Species-area Relationship

Alexander von Humboldt, a great German naturalist, and geographer, proposed a correlation between the species richness of an area and its geographic location. They found that the diversity of plants and animals increased as they expanded their observation area, but only up to a certain point. The relationship between species richness and area is represented mathematically as a rectangular hyperbola, and an equation can be used to describe it.

log S = log C + Z log A

• S = richness of species
• C = Y-intercept
• Z = regression coefficient
• A = Area

Importance of Species Diversity

• More diverse ecosystems are more productive. eg. An ecosystem with an exceptional variety of producer species will develop higher biomass to help the considerable biodiversity of consumer species.
• An ecosystem is more stable and sustainable when it has a greater biodiversity of species.
• The more diverse the ecosystem, the more considerable its ability to withstand environmental stresses such as drought or invasive infection.
• An ecosystem’s capacity to respond to any disaster is boosted by its species diversity.
  In communities with a biodiversity of species, each species can consume a varied proportion of the resources available as per their requirement. As an illustration, plants with smaller roots may access shallow soil’s water and minerals, while those with larger roots can access deeper soil.
• Rich biodiversity is necessary for ecosystem health and essential for the very survival of the people race on this world.
• Humans get several products from nature such as fruits, cereals, meat, wood, fiber, raisin, dyes, medicine, antibiotics, and other things.
  Biodiversity in large numbers supports large-scale interaction among organisms like- the food web.

Loss of Biodiversity

The biological diversity of our world has been rapidly decreasing and the accusing finger is directly pointing to human activities. Loss of biodiversity is primarily caused by overpopulation, urbanization and industrialization, and many other things. Human colonization of tropical Pacific islands has resulted in the disappearance of over 2,000 native bird species. According to the IUCN Red List (2004), 784 species have disappeared in the past 500 years, comprising 338 vertebrates, 359 invertebrates, and 87 plants. A few latest instances of recent extinctions are dodo (Mauritius), Quagga (Africa), Thylacine (Australia), Steller’s sea cow (Russia), and three sub-species (Bali, Javan, and Caspian) of the tiger. There have been 27 species that have disappeared in the past twenty years alone. 

Currently, the extinction threat impacts 12% of bird species, 23% of mammal species, 32% of amphibian species, and 31% of gymnosperm species worldwide. A thorough examination of the data reveals that amphibians seem to be more susceptible to extinction. The grim scenario of extinction is the fact that around 15,500 species worldwide are facing the threat of disappearance.

Causes of biodiversity Losses

The world is facing an accelerated rate of extinction of species highly As a consequence of human activities. The four major factors that cause of loss of biodiversity are referred to as The Evil Quartet”.these four major factors are mentioned below:

• Habitat Loss and Fragmentation:  As a result of pollution, urbanization, and other human activities, habitat loss and fragmentation are the leading causes of both animal and plant extinction and an important loss in species biodiversity. For instance, the Amazon rainforest (the planet’s lungs), which is the house of millions of species, is being cut down and removed for a variety of purposes. Tropical rainforest once constituted 14% of the landmass, but currently is not more than 6% As a result of the fragmentation of large habitats into small land spaces because of various human activities, mammals and birds that require extensive territories and migratory animals are badly affected.
• Over-Exploitation: Over-exploitation of natural resources leads to the extinction of several species. Humans overuse biological systems to obtain natural resources, which causes resource degradation and extinction. For Instance- Steller’s sea cow, the passenger pigeon, and many marine fishes are overharvested.
• Alien species invasions: When alien species are introduced deliberately or unintentionally, some of them become invasive, and cause the extinction of indigenous species. For Instance. As an illustration, the introduction of the Nile perch led to the extinction of cichlid fish in Lake Victoria. More than 200 species of cichlid fish in Lake Victoria in East Africa became extinct after the Nile perch was introduced to the body of water. Indigenous catfish in rivers are threatened by the unauthorized import of African catfish.
• Co-extinctions: When one species becomes extinct, the species that are connected with a species also becomes extinct. For Instance- the parasite also vanishes when its host fish does.

Why Should We Conserve Biodiversity?

There are several reasons, some obvious and others not so obvious, but all of which are particularly important. They can be classified into three categories is that narrowly utilitarian, broadly utilitarian, and ethical.

Narrowly Utilitarian

Humans derive a wide range (countless) of direct economic advantages from nature’s food (cereals, pulses, fruits), firewood, fiber, and construction suppliers, industrial products (tannins, lubricants, dyes, resins, perfumes) and goods with importance for medical value. More than 25 % of the drugs currently sold in the market globally are derived from plants and 25,000 plant species are used to make the traditional medicines used by indigenous humans around the world. Nations with rich biodiversity can expect huge advantages as increasingly many other things are being put into ‘bioprospecting’.

Broadly Utilitarian 

According to the broadly utilitarian position, biodiversity is crucial to many ecosystem services that are provided by nature. According to estimates, the fast Amazon forest produces 20% of the total oxygen in the Earth’s atmosphere through photosynthesis. pleasures of the senses, such as strolling through a forest or waking up to the music of a bulbul, etc.

Ethical

It is our moral obligation to protect other species since they have intrinsic value and should continue to pass on their biological heritage to the next generations in healthy conditions.

Conservation of Species Diversity

Every species plays an important role in an ecosystem. Biodiversity is essential to conserve diversity because if it is once extinct, biodiversity can be preserved in a variety of ways.

• In-situ conservation: Biodiversity-rich areas are protected as biosphere reserves, national parks, and sanctuaries are referred to as in-situ conservation. Protecting Sunderbans for several endangered species such as- the royal Bengal tiger, olive ridley sea turtles, mangrove species, and many other things.
• Ex-situ conversation: Its Occurs when endangered and threatened species are located, removed, and preserved in designated areas like botanical gardens, wildlife safaris, etc. with full protection.

FAQs on Biodiversity and Conservation

Q1: What is biodiversity and why it’s necessary?

Answer:

Biodiversity is the natural world around us, and the variety of all of the different kinds of organisms – the plants, animals, insects, and microorganisms that live on our planet. Every one of these lives and work together in ecosystems to maintain and support life on earth, and exist in delicate balance.

Q2: How Many types of Biodiversity in our Planet?

Answer:

Biodiversity mainly three types are that genetic diversity, species diversity, and ecosystem diversity.

Q3: What is The Definition of Species Diversity?

Answer:

The number of species and the abundance of each species living in a particular area is known as species diversity.