Exercises: Forest: Our Lifeline | Class 7 Oxford Science: Chapter Notes, Worksheets & Tests PDF Download

Objective Type Questions 

Roots of trees help to bind soil together and prevent its erosion.
The roots of trees hold the soil together and prevent it from being washed away by wind or water. This helps in soil conservation and prevents soil erosion.

Q.2. Animals are called _____________(producers/consumers) because they depend on plants and other animals for their food. 

Animals are called consumers because they depend on plants and other animals for their food.
Consumers are organisms that feed on other organisms to obtain their food. Animals depend on plants and other animals for their nutrition, making them consumers in the food chain.

Q.3. Trees help to regulate the _________(soil type/climate) of a place. 

Trees help to regulate the climate of a place.
Trees play a significant role in regulating the climate of a place. They absorb carbon dioxide from the atmosphere and release oxygen, which helps to purify the air. Trees also help to reduce the amount of carbon dioxide in the air, which is a major greenhouse gas responsible for global warming.

Q.4. ____________(Food chain/Food web) is a complex representation of energy flow in nature. 

Food web is a complex representation of energy flow in nature.
A food web is a representation of the interconnecting food chains that exist in an ecosystem. It shows how different organisms are connected to each other through their feeding habits. A food web is a more complex representation of energy flow in nature than a food chain.

Q.5. Forests play a vital role in releasing large amounts of __________(oxygen/ carbon dioxide) in the air. 

Forests play a vital role in releasing large amounts of oxygen in the air.
Trees are the primary source of oxygen in the atmosphere. They absorb carbon dioxide during photosynthesis and release oxygen as a by-product. Forests play a crucial role in maintaining the oxygen balance in the atmosphere and are essential for the survival of living organisms.

B. Choose the Correct Option.

Very Ahort Answer Type Questions 

Teak, Sal

Q.2. Things made from resins. 

Varnish, Adhesives

Q.3. Animals that depend on forests for shelter 

Deer, Squirrels

Q.4. Common pollinators 

Bees, Butterflies

Q.5. Natural disasters commonly caused by deforestation 

Landslides, Floods

Short Answer Type Questions 

Trees help in regulating the climate of the place by absorbing carbon dioxide from the atmosphere through the process of photosynthesis and releasing oxygen. This helps in reducing the amount of greenhouse gases in the atmosphere, which otherwise would have led to an increase in global warming and climate change. Additionally, trees also help in reducing the temperature of the area by providing shade and releasing water vapor through transpiration.

Q.2. What is a biotic community? 

A biotic community refers to the group of living organisms that coexist in a particular habitat and interact with each other. This community may include plants, animals, fungi, and microorganisms, all of which are interdependent and play a crucial role in maintaining the balance of the ecosystem.

Q.3. What role do coconut and palm trees play in providing protection in coastal areas?

Coconut and palm trees play a crucial role in providing protection in coastal areas. These trees have deep roots that help in stabilizing the soil and preventing soil erosion, which is a common problem in coastal areas due to the action of waves and tides. Additionally, the leaves and branches of these trees act as a barrier and reduce the impact of strong winds and storms, thereby protecting the coastal areas from damage. The coconut and palm trees also act as a natural habitat for many species of birds and animals, which contribute to the biodiversity of the coastal ecosystem.

Long Answer Type Questions 

If forests disappeared, it would have a catastrophic impact on our planet. Forests are essential for maintaining the balance of nature. They provide oxygen, absorb carbon dioxide, regulate the temperature, and prevent soil erosion. Without forests, there would be an increase in greenhouse gases, leading to global warming, climate change, and natural disasters like floods, droughts, and hurricanes. Moreover, forests are home to numerous species of plants and animals, and their disappearance would lead to the extinction of many species, disrupting the food chain and the ecosystem. Forests also provide us with timber, medicine, and other resources, and their disappearance would lead to an economic crisis. Therefore, it is crucial to conserve our forests.

Q.2. Explain some measures that can help us conserve our forests. 

There are several measures that can help us conserve our forests:

Afforestation: planting new trees in areas where forests have been destroyed or degraded.

Reforestation: restoring damaged forests by replanting native tree species.

Forest conservation: protecting forests from deforestation, illegal logging, and encroachment.

Sustainable forest management: using forest resources in a way that does not harm the environment, and balancing the economic, social, and ecological benefits of forests.

Community participation: involving local communities in forest conservation and management, and providing them with alternative livelihoods.

Awareness and education: creating awareness about the importance of forests and the threats they face, and educating people on sustainable forest management practices.

Q.3. What is a food chain and a food web? Illustrate the difference with examples. 

A food chain is a sequence of organisms in which each organism feeds on the one below it, and is itself eaten by the one above it. For example, a simple food chain in a forest ecosystem could be: grass → rabbit → fox. Here, the grass is eaten by the rabbit, which is eaten by the fox.

A food web, on the other hand, is a network of interconnected food chains in an ecosystem. It shows the complex interactions between different species and their feeding relationships. For example, a food web in a forest ecosystem could be: grass → rabbit → fox; grass → deer → wolf; grass → mouse → owl. Here, the grass is eaten by different herbivores, which are in turn eaten by different carnivores. The mouse is eaten by the owl, which is not connected to the other food chains. The food web is more realistic than the food chain, as it takes into account the fact that most organisms feed on multiple prey and are themselves eaten by multiple predators.