DAV Class 7 Science Chapter 15 Forests Question Answer Notes
DAV Class 7 Science Chapter 15 Forests Question Answer Notes Solution by Expert Science Teacher. DAV Class 7 Science 15th Chapter Forests for Students of DAV Schools.
Lesson No 15
Forests
A.) Fill in the blanks.
Answer: (1) recycling (2) understory (3) Oxygen, CO2 (4) fertility, erosion (5) Banyan
B.) Write True or False for the following statements.
Answer: (1) False, they do not depend on man (2) False, they are co dependent(3) True (4) True (5) True
C.) Tick the correct option.
1.) The layer of forest, where intertwined branches of trees are found, is known as the
Answer: canopy
2.) Decomposers help in
Answer: recycling of nutrients
3.) An increase in cutting down of the trees in forests will lead to
Answer: an increase in the amount of carbon dioxide in air.
4.) The tree, that is thought of as an ‘immortal tree, is the
Answer: banyan tree
5.) The tree that is often referred to as “The golden shower tree” is the
Answer: amaltas tree
D.) Answer the following questions in brief.
1.) Define the terms ‘food chain’ and ‘food web’.
The logical structure of living things known as a food chain is how nutrients as well as energy are transferred from one type of organism to another. It shows how every animal in an ecosystem depends on the animal that came before it for sustenance. For instance, in a simple food chain, a plant is eaten by a herbivore, who then passes it on to a predator. A food web, on the other hand, is a very complex network of connected food chains that exemplifies the interactions between small animals within an ecosystem. It shows how different species are interrelated and how the appearance or extinction of one animal could have an impact on the environment as a whole.
2.) Name the different layers of the forest.
Forests are complex ecosystems that are made up of several layers, each with its own unique characteristics and inhabitants. The main layers of a forest are:
The canopy, or upper level of the forest, is made up of the crowns of the tallest trees.
The understory level, which is found beneath the canopy, is made up of fruiting trees, bushes, and grass species.
Forest ground: This lowest layer of the forest is made up of the ground and the debris that has fallen from the uppermost layers of the forest, including twigs, branches, and other items.
A layer of soil composed of bacteria, organic material, as well as mineral soil lies beneath the forest floor.
The roots of the trees and other plants in the forest make up the layer of roots that builds up the ground beneath.
3.) Give the meaning of the term ‘soil erosion’.
The procedure of soil particles becoming separated and moved by air, rain, or snow results in the erosion of topsoil from the earth’s surface. Crop yields may decline, soil fertility may decline, and the environment may deteriorate as a result.
4.) Name four useful products that are provided to us by the forests.
Forests are a valuable resource that provide a wide range of products and services to humans. Some of the useful products provided by forests include:
Timber: Woods are a major source of wood, which is used to make a number of products, including furniture, papers, and other wood-based goods like lumber.
Forests also provide a variety of different plant-based goods that are utilised in nutrition, healthcare, and numerous other purposes, in addition to a variety of timber products.
Biodiversity: Forests are home to a wide range of animal and plant species, many of which have important ecological, cultural, and therapeutic value.
Carbon sequestration, regulating functions, soil management, water quality control, as well as biodiversity preservation are additional ecological services that woods provide.
5.) Name any four trees that are common to the Indian sub-continent.
There are many different types of trees found in the Indian sub-continent, but here are four that are commonly found:
One of the most recognisable trees on the Indian subcontinent is the banyan tree, which is regularly referred to as India’s national tree. Neem tree: Native to the Indian subcontinent, the neem tree is a tropical tree. It is a tree that grows quickly and has a good reputation for being medicinal. Peepal tree: Another name for the peepal tree is the sacred fig. With a maximum height of 30 metres, it is a sizable tree. Native to the Indian subcontinent, the sandalwood tree is a smaller to medium-sized evergreen tree.
E.) Answer the following questions.
1.) Comment on the statement: “Early man began his life as a forest dweller.”
Since archaeological evidence demonstrates that early humans lived in forested areas, this assertion is generally regarded to be correct. They thrived in their new surroundings because they had access to necessities like food and shelter. Early humans were able to travel out of the forest as well as live in much more open places as they acquired tools and abilities, enabling the development of more complex groups.
2.) How are the shapes of crowns of trees, and their location on earth, related to each other?
Because the climate in which a tree develops will have an impact on those shapes, the shapes of tree canopy and their locations on earth are related. For instance, trees often grow more open, flat canopies that offer less wind shelter in locations with greater winds. On the other hand, the crowns of trees in protected regions are frequently denser and rounder. Additionally, due to their natural adaptation to their surroundings, several tree species have diverse crown morphologies.
3.) State any five points highlighting the importance of forests to mankind.
Forest trees and other vegetation release oxygen to the environment as an outcome of photosynthesis. This oxygen is essential for human and other animal survival. For humans, animals, and birds, forests offer a source of food. Vegetables, nuts, honey, and other food items can be found in forests. Forests offer a variety of wildlife as well as birds shelter. They also provide protection from weather-related disasters including flooding, thunderstorms, and subzero temperatures. In addition to regulating the levels of carbon and nitrogen dioxide in the atmosphere, forests are essential for maintaining the ecological equilibrium. For example, forests provide raw materials for the production of paper and wood for the construction industry.
4.) Discuss, in brief, the likely consequences of deforestation.
There are several detrimental long- and short-term repercussions that might come from deforestation. The immediate repercussions include soil deterioration and a reduction in biodiversity. Long-term repercussions include an increase in global warming caused by the release of carbon dioxide stored in the atmosphere, a decrease in the quantity of water available, as well as a rise in air pollution caused by the burning of forests. Deforestation can also affect regional and global climate, which increases the likelihood of severe weather events. Lastly, communities that rely on the woods for their food may be compelled to relocate as a result of deforestation.
5.) How are the Eucalyptus tree, Teak tree and the Neem tree important for us?
The eucalyptus tree is valued for its medicinal properties; furniture is made from its wood, and many drugs use eucalyptus oil. Teak wood is appreciated for its durability and hardness and is used to manufacture furniture and boats. Numerous ayurveda remedies make use of the leaves of the Neem tree, which is notable for its therapeutic advantages. Neem oil can also be used for pest control because it naturally repels insects.
More Extra Questions for Preparation
Chapter 15. Forests
Q.1.) Fill in the blanks.
1.) The largest area of rain forest is in South America.
2.) Animals that eat both plants and other animals are called omnivorous.
3.) Gangetic Sunderban is the largest mangrove area in India.
4.) Interconnected food chains form a food web.
5.) Teak is used for making furnitures and doors.
Q.2. True or false.
1.) The herbivores consume plants and are, in turn, eaten by the carnivores.
Answer – True
2.) Understory layer is made up of decomposing leaves.
Answer –False
3.) Forests maintain soil fertility.
Answer – True
Q.3.) Match the pair.
1. Neem | a. Deforestation |
2. First national park | b. Miracle tree |
3. Cutting of trees. | c. Canopy |
4. Mass of interwind branches | d. Banyan |
5. National tree | e. Cobert |
Answer – 1- b,2- e, 3- a, 4- c, 5 -d.
Q.4.) Choose the correct answer.
1.) The shape of the crowns of trees depends on their
a.) Height
b.) Size
c.) Both a and b
d.) Location
Answer – d.) Location
2.) Non- living components of forest include
a.) Soil
b.) Water
c.) Minerals
d.) All of the above
Answer – d. All of the above
3.) In food chain, plants to plant eaters are called
a.) Herbivores
b.) Carnivores
c.) Both a and b
d.) None of these
Answer – a.) Herbivores
4.) is tall evergreen tree.
a.) Neem tree
b.) Banyan tree
c.) Eucalyptus tree
d.) Teak
Answer – c.) Eucalyptus tree
Q.5. Write short answers.
1.) Define forest.
Answer – A forest is an area with a high density of trees.
2.) Name biotic components.
Answer – Trees, shrubs, vines, grasses and other herbaceous (non-woody) plants, mosses, algae, fungi, insects, mammals, birds, reptiles,etc are biotic components.
3.) Living organisms can be classified by what?
Answer – Living organisms are classified as autotrophs, heterotrophs, and saphrotrophs.
4.) What are decomposers?
Answer – Decomposers break down the rough, woody fibres of trees, enabling the nutrient cycle to begin all over again.
Q.6.) Answer the following.
1.) Explain any one common tree in India.
Answer –
a.) Teak is one of the most popular trees of India. It is mainly used in the making of furniture and doors.
b.) Teak also has medicinal value.
c.) The bark is a bitter, health giving tonic and is considered useful in fever.
2.) What is carbon cycle?
Answer – The carbon cycle
a.) Forests act as a major ‘carbon store. Carbon dioxide (CO) gas is taken up from the atmosphere by trees and plants, and used for photosynthesis.
b.) When forests are cleared, and the trees are either burnt or allowed to rot, carbon gets released in the form of CO2, gas.
c.) This leads to an increase in the atmospheric CO, concentration.
d.) Carbon dioxide gas is a major contributor to the greenhouse effect.
3.) Forests are known as lungs of the earth. Give reason.
Answer – Forests provide clean air as they are the reservoirs of life giving oxygen. They help to maintain the oxygen-carbon dioxide ratio in the atmosphere. They are, therefore, known as the lungs of the earth.
4.) Write a note on Amazon forest.
Answer –
a.) The largest area of rain forest is in South America. It is called the Amazon rain forest.
b.) Over 3,000 kinds of trees grow in this rain forest. Many kinds of flowers also grow here.
c.) The Amazon rain forest is very important for all of us. Some people call the Amazon Rain forest the “lungs of the world.” The very many trees and other plants here give off lots and lots of oxygen. d.People and animals, all need oxygen to breathe. The Amazon rain forest ‘breathes out’ more than 20 per cent of the world’s oxygen supply.
5.) What are the layers of forest?
Answer – The Layers of the Forest are
a.) Forest Floor Layer
b.) Understory layer
c.) Canopy
d.) Emergent layer
6.) Write few points on importance of forest.
Answer –
a.) Forests also reduce the speed of strong winds and trap dust and gases.
b.) Forests are used as medicine.
c.) Forests are also used for making furnitures and doors.
d.) Forests also maintain soil fertility.