Conservation Of Plants And Animals: Class 8 Science Guide

Understanding the Main Threat: Deforestation

The greatest danger to the survival of plants and animals is the loss of their home, or habitat. The primary cause of this is deforestation, which means clearing forests and using that land for other purposes. But why does this happen? The main reasons include clearing land for agriculture to feed a growing population, building cities, factories, and roads (urbanization and industrialization), and using wood for fuel or making furniture.

The consequences are severe. Trees absorb carbon dioxide, a gas that traps heat. Fewer trees mean more carbon dioxide in the atmosphere, leading to global warming. Deforestation also disrupts the water cycle, which can lead to less rainfall. Without tree roots to hold the soil together, it gets washed or blown away, a process called soil erosion. This can slowly turn fertile land into a desert, a process known as desertification. Most importantly, it destroys the homes of countless species, pushing them towards extinction.

Key Terms in Conservation

Biodiversity

Short for 'biological diversity', it refers to the variety of all living organisms—plants, animals, fungi, and microorganisms—found in a particular area.

Flora and Fauna

Flora refers to all the plant life present in a specific region or time, while Fauna refers to all the animal life of that region or time.

Endemic Species

These are species of plants and animals that are found exclusively in a particular geographical area and nowhere else in the world. For example, the Sal tree and wild mango are endemic flora of the Pachmarhi Biosphere Reserve.

Endangered Species

These are animals whose numbers are diminishing to a level that they might face extinction. The tiger, snow leopard, and one-horned rhinoceros are examples.

Extinct Species

These are species that no longer exist anywhere on Earth. The Dodo bird and the dinosaurs are famous examples of extinct species.

How We Conserve: A Look at Protected Areas

1. Step 1: Wildlife Sanctuaries — These are protected areas where animals are kept safe in their natural habitat. Killing (poaching) or capturing animals is strictly forbidden. However, some human activities like grazing by local livestock or collecting firewood may be allowed to a limited extent, as long as it doesn't harm the wildlife.
2. Step 2: National Parks — These are large areas that are strictly reserved to preserve flora, fauna, landscape, and historic objects of an area. They offer a higher degree of protection than sanctuaries. Human activities like grazing, forestry, or cultivation are not permitted. Even private ownership rights are not allowed.
3. Step 3: Biosphere Reserves — These are very large, multi-purpose protected areas created to conserve biodiversity as a whole. They not only protect the flora and fauna but also the traditional lifestyle of the tribal people living in the area. A biosphere reserve is often divided into three zones: a Core Zone (strictly protected), a Buffer Zone (limited human activity like research), and a Transition Zone (sustainable human settlement and activity).

Important Tools and Concepts in Conservation

• Red Data Book: This is a special book that maintains a record of all endangered plants and animals. It is published by the International Union for Conservation of Nature (IUCN). Different colored pages (e.g., red for critically endangered) indicate the threat level for various species.
• Migration: This is the seasonal movement of animals (especially birds) over long distances. They do this to find better weather, food, or breeding grounds. For example, Siberian Cranes migrate from Siberia to warmer places in India, like Bharatpur, during winter.
• Project Tiger: This was a major wildlife conservation project launched in India in 1973 to save the tiger population. It has been very successful in increasing the number of tigers in dedicated Tiger Reserves across the country.
• Reforestation: This is the opposite of deforestation. It means restocking a destroyed forest by planting new trees. If the deforested area is left undisturbed, it can re-establish itself naturally over time. However, planting trees speeds up the process.

Practice Questions with Solutions

• Q: What is deforestation? List any three consequences of deforestation. A: Step 1: Define deforestation. Deforestation is the large-scale cutting and clearing of forests to use the land for other purposes, such as agriculture, industries, or building homes. Step 2: List three major consequences. 1. Global Warming: Trees use carbon dioxide (CO2). Fewer trees mean more CO2 in the atmosphere, which traps heat and warms the planet. 2. Soil Erosion: Tree roots hold soil together. Without them, soil is easily washed away by rain or blown by wind, making the land infertile. 3. Loss of Habitat: Forests are home to millions of animal and plant species. Clearing forests destroys their homes, leading them to become endangered or extinct. Final answer: Deforestation is the clearing of forests. Its consequences include global warming, soil erosion, and the loss of habitat for wildlife.
• Q: How is a wildlife sanctuary different from a national park? Give one key difference. A: Step 1: Recall the definition of a wildlife sanctuary. A wildlife sanctuary is a protected area where animals are protected from hunting, but some human activities like limited grazing may be allowed. Step 2: Recall the definition of a national park. A national park is a strictly protected area where flora, fauna, and the landscape are preserved. No human activities are generally permitted. Step 3: Identify the key difference. The main difference lies in the level of restriction on human activities. National parks are more restrictive than wildlife sanctuaries. Final answer: The key difference is that national parks have stricter rules and do not permit human activities like grazing or collection of forest produce, whereas wildlife sanctuaries may allow some of these activities to a limited extent.
• Q: What are endemic species? Why are they at a greater risk of extinction? A: Step 1: Define endemic species. Endemic species are those species of plants and animals that are found exclusively in one particular geographic area and nowhere else on Earth. Step 2: Explain their vulnerability. Since they live only in one specific location, if their habitat is destroyed or threatened by disease or human activity, they have nowhere else to go. Step 3: Conclude why the risk is greater. Unlike species that are widespread, endemic species cannot migrate or repopulate from other areas. Therefore, destruction of their single habitat can lead to their complete extinction. Final answer: Endemic species are found only in a specific area. They are at a greater risk of extinction because the destruction of their limited habitat means they lose their only home in the world, with no other populations to ensure their survival.
• Q: Explain the role of the Red Data Book in conservation. A: Step 1: Identify what the Red Data Book is. The Red Data Book is a public document created to record rare and endangered species of animals, plants, and fungi. Step 2: Explain its purpose. Its primary purpose is to provide detailed information for studies and monitoring programs on species that are at risk of extinction. Step 3: Describe how it helps in conservation efforts. By identifying and documenting species in danger, it helps governments and conservation organizations to prioritize their efforts and create strategies to protect these species before they become extinct. Final answer: The Red Data Book acts as a crucial alert system for conservation. It keeps a record of endangered species, helping conservationists identify which species are in most danger and need immediate protection to prevent their extinction.

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