WBBSE Solutions For Class 8 School Science Chapter 10 Biodiversity Environmental Crisis and Conservation of Endangered Animals Short Answer Type Questions

Chapter 10 Biodiversity, Environmental Animals Short Answer Type Questions

 

Question 1. Why is there no waste in a forest? Name some plants of mangrove forest.
Answer:

There Is no waste in a forest:-

When the animals die in a forest, they are eaten up by scavengers (vultures, jackals, etc). The decomposers (bacteria and fungi) decompose the dead plant matter, dead animals, and animal wastes present in the forest into mineral salts (in the form of humus), water, and COy which go into soil and air (and hence recycled for the growth of new vegetation).

Since dead animals are eaten up and the materials present in dead plants, dead animals, and animal wastes are recycled, therefore there is no waste left in a forest. Garjan, Garan, Kankra, Keora, Pasur, etc are the plants found in the mangrove forest.

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Question 2. What is a forest? Mention a few forest products that are put to use.
Answer:

Forest:-

A forest is a large area of land covered with trees or other woody vegetation. Hundreds of more precise definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function.

According to the widely- used United Nations Food and Agriculture Organization definition, forests covered an area of approximately 30.6 percent of the world’s land area in 2015.

Components of forests

 

WBBSE Solutions For Class 8 School Science Chapter 10 Biodiversity, Environmental Crisis and Conservation of Endangered Animals Compents of forests

Plants: A forest has many plants (including trees) that are called producers or autotrophs.

Animals: The animals of a forest are called consumers. They may be herbivores or carnivores. The animals are together called heterotrophs.

Decomposers: The microorganisms which break down the dead parts of plants and dead bodies of animals into simple substances such as mineral salts, C02, and water (which can be reused by plants) are called decomposers. These include fungi, bacteria, etc which are saprotrophs.

The decomposers return the nutrients present in dead plants and animals to the soil to maintain the supply of nutrients to the plants. prevent the piling up of dead plants, dead animals, and animal wastes inside the forest by carrying out decomposition.

Scavengers: Those animals which eat dead animals are called scavengers. Vultures, crows, jackals, etc are scavengers. They eat up dead bodies to keep the forest environment clean.

The forest is an ecosystem of self-sufficient units of living things and nonliving environments

Question 3. How does a mother octopus take care of the eggs and the young ones?
Answer:

Mother octopus lays small eggs of round shape like the size of grapes. She guards the eggs until they are hatched. She does not even go to eat, lest crab or other animals harm the eggs.

The mother octopus looks after the progenies till she dies by inches due to starvation. The baby octopuses spread out after the eggs are hatched. Lastly, the body of the mother octopus sinks slowly under the water in the ocean.

Question 4. Give examples of the biodiversity of temperate coniferous forests.
Answer:

Examples of the biodiversity of temperate coniferous forests:-

Dominant tree species found in temperate coniferous forests include cedar, cypress, Douglas fir, pine, spruce and redwood.

There are some deciduous trees such as maple, and mosses and ferns are common. Examples of animals that live in temperate coniferous forests are deer, marmot, elk, black bear, salmon, spotted owl, etc.

Question 5. What is meant by plantation forests?
Answer:

Plantation Forests:-

Planted forests are generally defined according to the extent of human intervention in the forest’s establishment and/or management, which depends, to a large extent, on the purpose of growing the forest. Examples include Sal, Teak, coconut, and betel plantations.

Question 6. What is Savanna?
Answer:

Savanna:-

Savanna is grassland with scattered individual trees. Savannas of one sort or another cover almost ha If the surface of Africa (about five million square miles, generally central Africa) and large areas of Australia, South America, and India.

The climate is the most important factor in creating a savanna. Savannas are always found in warm or hot climates where the annual rainfall is from about 50.8 to 127 cm (20-50 inches) per year.

Question 7. Explain some common adaptations of Xerophytic plants.
Answer:

Some Common Adaptations Of Xerophytic Plants:-

Xerophytes resist the dryness of the desert and can live for many years with the help of a little bit of water. Some of the adaptations that they exhibit are as follows:

  1. Xerophytes store water in their bodies. As a result, their root and trunk become very large and thick.
  2. They have thorns in place of leaves.
  3. They limit water loss by having a covering called a cuticle all over the body.
  4. The roots of a few plants penetrate deep into the soil, digging sands in search of water. The root caps are very strong.
  5. To prevent water loss, a very limited number of stomata are present in the leaves.

Question 8. What is a forest fire? How it is caused?
Answer:

Forest Fire:-

A forest fire is an uncontrolled fire occurring in nature. Sometimes, the forest fire is so large that it takes a long time for the firefighting crews to gain control of the situation.

This could result in massive destruction. Causes of forest fires can be of two types- environmental and human-related. Climatic conditions are the factors that have the greatest impact on the extent of forest fires.

The forest is most vulnerable in spring and summer seasons when there are long dry spells. Weather conditions such as precipitation and wind, as well as the layout of the terrain, are important factors in determining the size of the forest fire. Lightning strikes and volcanic eruptions are other environmental causes.

It is estimated that as many as nine out of ten forest fires are caused by humans, although the causes of a significant number of forest fires remain unknown.

The most common cause of such fires is the use of open flames and disposable barbecue grills. Even a cigarette that is not properly extinguished can cause a forest fire.

Question 9. Mention a few causes of deforestation.
Answer:

Deforestation

Deforestation is the permanent destruction of forests in order to make the land available for other uses. anthropogenic forest fires, pollution, and climate change are all having negative impacts on forest biological diversity.

As forests are degraded, so too is biological diversity. This degradation lowers the resilience of forest ecosystems and makes it more difficult for them to cope with changing environmental conditions.

fires lit intentionally by people living around forests for cooking. It has been estimated that 90% of forest fires in India are man-made.

Effects of a forest fire: Fires are a major cause of forest degradation and have wide-ranging adverse ecological, economic, and social impacts, including:

  1. Loss of valuable timber resources, Loss of biodiversity, and extinction of plants and animals,
  2. Loss of wildlife habitat and depletion of wildlife,
  3. Loss of natural regeneration and reduction in forest cover,
  4. Loss of carbon sink resources and increase in the percentage of C02 in the atmosphere,
  5. Ozone layer depletion, soil erosion, frequent flooding, climate change, etc.
  6. Health problems leading to diseases,
  7. Loss of livelihood for tribal people.

Causes: There are many causes of deforestation. The WWF reports that half of the trees illegally removed from forests are used as fuel.

Some other common reasons are:

  1. To make more land available for housing and urbanization,
  2. To harvest timber to create commercial items such as paper, furniture, and homes,
  3. To create ingredients that are highly prized consumer items, such as the oil from palm trees,
  4. To create room for cattle ranching.

Deforestation and climatic change: The main problem caused by deforestation is the impact on the global carbon cycle. Gas molecules that absorb thermal infrared radiation are called greenhouse gases.

If greenhouse gases are in large enough quantity, they can force climate change The deforestation of trees not only lessens the amount of carbon stored, but it also releases carbon dioxide into the air.

This is because when trees die, they release the stored carbon. Deforestation is the second largest anthropogenic (human-caused) source of carbon dioxide in the atmosphere, ranging between 6 percent and 17 percent.

Carbon isn’t the only greenhouse gas that is affected by deforestation. Water vapor is also considered a greenhouse gas.

The impact of deforestation on the exchange of water vapor and carbon dioxide between the atmosphere and the terrestrial land surface is the biggest concern with regard to the climate system. Changes in their atmospheric concentration will have a direct effect on climate.

Other effects of deforestation: Forests are complex ecosystems that affect almost every species on the planet. When they are degraded, it can set off a devastating chain of events both locally and around the world.

Question 10. Write about the biodiversity of Northern West Bengal forests.
Answer:

Biodiversity of Northern West Bengal forests:-

In North Bengal, the forest areas are mainly situated in the Terai-Duars region. However, the zone is interspersed with human settlements, tea gardens, rail, and roadways.

Trees like sal, Gamhar, Odal, Khair, Sishu, and Emblica are observed in the Dooars and Terai forests and plants like Rhododendrons and Pine are in the slopes of the high mountains of North Bengal.

This region of the state is the habitat of other large mammals like the Rhinoceros, Tiger, and Gaur,s, and many other smaller vertebrates, like deer, wild goats, hares, wild hens, and peacocks.

There are 16 mammals listed in the Red Data Book of IUCN. The forests here host 50-60% of the species richness of the state. Notified Protected Areas cover 1225 sq. km i.e., 55% of the forests in Northern Bengal.

Question 11. Write about the zones of an ocean.
Answer:

Zones of an ocean:-

The open water of the ocean is known as the limnetic or pelagic zone; the oceanic zone refers exclusively to waters not lying over the continental shelf and neritic refers to those coastal waters over the shelves.

In the oceans, the benthic zones are the littoral, which here means the area between high tide and 100 m deep and has nothing to do with plant life;

it includes the continental shelf, which extends to about 100 m deep; the bathyal zone which extends to 2000 m (below the photic zone or LCP), the abyssal zone from 2000 to 4000 m, and the deep oceans or hadal zone from 4000 to 10,000 m.

Question 12. What is bioluminescence?
Answer:

Bioluminescence:-

Bioluminescence is the production and emission of light by a living organism (mostly marine) that reside at 200-1000 m depth of the ocean.

It is a form of chemoluminescence. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some fungi, microorganisms including some bioluminescent bacteria, and terrestrial invertebrates such as fireflies.

Luciferin, a protein-bound pigment, and Luciferase, an enzyme, are present in the bodies of bioluminescent organisms. In the presence of the enzyme, a chemical reaction between luciferin and oxygen occurs transforming chemical energy into light energy. This produces cool light or bioluminescence.

Other than this, some marine animals develop a symbiotic relationship with light-producing bacteria to produce light. Bioluminescence helps organisms to search for food, attract prey, for mimicry and self-defense, etc.

Question 13. What are planktons?
Answer:

Planktons:-

Plankton is the foundation of the ocean food web. The word plankton comes from the Greek word “plankton” which means drifting.

Planktons, marine and freshwater organisms that, because they are non-motile or because they are too small or too weak to swim against the current, exist in a drifting, floating state.

The term plankton is a collective name for all such organisms and includes certain algae, bacteria, protozoans, crustaceans, mollusks, and coelenterates, as well as representatives from almost every other phylum of animals.

Planktons consist of phytoplankton and zooplankton. Phytoplanktons live in the euphotic zone and can do photosynthesis. Diatoms, kelp, and Dinoflagellates are phytoplanktons.

Zooplanktons are mainly larvae of marine animals that float on the upper layer of the ocean. They cannot swim but drift around to avoid enemies or search for food. All of them are not microscopic.

Question 14. Name the following desert plants.
Answer:

  1. the bark of these trees is used as p.o.c d bowl
  2. the wood of these plants is used to make houses and strong ropes
  3. these plants protect the sand dunes of the desert.
  4. Joshua plant
  5. Saguaro cactus
  6. Mesquite plant

Question 15. What is aestivation? Why are Gerbils called Kangaroo rats?
Answer:

Aestivation:-

When the temperature in the desert rises, some animals go to deep sleep. This phenomenon is called aestivation. The rate of heartbeat and respiration falls during this time.

Gerbils are small rat-like nocturnal animals. They live inside the sand by digging it. They can jump like a kangaroo. Hence they are known as Kangaroo rats.

Question 16. What is fire algae? Name a few algae that are found in the saline water of the ocean.
Answer:

Fire Algae:-

Dinoflagellates are called fire algae as their all members show bioluminescence. Green algae, Golden and Yellow-green algae, Brown algae, Red algae, Dinoflagellates, and Blue Green algae are found in saline water.

Question 17. Write briefly about how jellyfishes and squids carry out locomotion.
Answer:

Jellyfishes And Squids Carry Out Locomotion:-

Jellyfish: Jellyfish are the major non-polyp form of individuals of the phylum Cnidaria. They are typified as free-swimming marine animals consisting of a gelatinous umbrella-shaped bell and trailing tentacles.

The bell can pulsate for locomotion while stinging tentacles can be used to capture prey. Jellyfish are found in every ocean, from the surface to the deep sea.

Jellyfish have tiny stinging cells in their tentacles to stun or paralyze their prey before they eat them. Inside their bell-shaped body is an opening that is their mouth. They eat and discard waste from this opening.

 

WBBSE Solutions For Class 8 School Science Chapter 10 Biodiversity, Environmental Crisis and Conservation of Endangered Animals jelly fish

 

Squid and Cuttlefish: The Squid is an invertebrate (animal without a backbone) that swims in the oceans. This mollusk is closely related to the octopus.

Squids can change the color of their skin to mimic their environment and hide from predators. Squids are soft-bodied cephalopods.

They move by squirting water from the mantle through the siphon, using a type of jet propulsion. When in danger, squid squirt a cloud of dark ink in order to confuse their attacker and allow the squid to escape. Squids reproduce by releasing eggs into the water.

Cuttlefish have a unique internal shell, the cuttlebone. Despite their name, cuttlefish are not fish but mollusks. Cuttlefish have large, W-shaped pupils, eight arms, and two tentacles furnished with denticulated suckers, with which they secure their prey.

Cuttlefish eat small mollusks, crabs, shrimp, fish, octopodes, worms, and other cuttlefish. Their predators include dolphins, sharks, fish, seals, seabirds, and other cuttlefish.

 

WBBSE Solutions For Class 8 School Science Chapter 10 Biodiversity, Environmental Crisis and Conservation of Endangered Animals Squid and cuttle fish.jpg

 

 

Question 18. How do polar bears survive in the Arctic region? The polar bear lives in the extremely cold climate of the Arctic region due to the following adaptations:
Answer:

  1. The polar bear has a white color that matches its surroundings. This helps it to catch its prey and also protects it from its predators.
  2. The polar bear has two thick layers of fur on its body that protect it from extreme cold by preventing heat loss from the body.
  3. It also has fur on its feet and toes that protects it when it walks on snow and ice.
  4. The polar bear has a thick layer of fat under the skin.
  5. The polar bear has a rounded body and small ears to keep the body surface area to a minimum (compared to the body weight) to reduce heat loss from the exposed surface.
  6. The polar bear has big paws to walk on snow without sinking.
  7. He is a good swimmer.
  8. A polar bear has a strong sense of smell that helps in locating and catching its prey for food.

Question 19. What are deserts? Mention the types of deserts.
Answer:

Deserts:-

A desert is an endless barren area of land where little precipitation occurs and consequently living conditions are hostile for plant and animal life.

The lack of vegetation exposes the unprotected surface of the ground to the processes of denudation. Deserts are found in the western part of North America, Western Asia, Central Australia, South America, and South and North Africa.

The two major classifications are hot and cold. Many, such as the Sahara, Thar, etc. are very hot during the day and have cold nights, but there are also deserts such as the Atacama in South America or the Gobi in Asia which remain frozen day and night.

Question 20. Mention the crisis that the penguins are facing today.
Answer:

The crisis of penguins is described as follows:

  1. The loss of sea ice due to global warming is harming Emperor penguin chicks and adults. Emperor penguins rear their chicks on land-locked sea ice.
  2. When sea ice breaks up before the chicks mature, chicks get swept into the water and are likely to die. For adults, the loss of sea ice leads to lower food availability which can result in increased mortality.
  3. Penguin colonies have been slaughtered by men for their fat. Soaps and oils are manufactured from penguin oil. Penguin oil is also used to prepare medicines.
  4. Penguin feathers are used to make clothes, hats, shoes, and bags.

Question 21. Write briefly about the adaptations of a camel.
Answer:

Desert adaptations

Plants and animals living in the desert need special adaptations to survive in harsh environments. Plants tend to be tough and wiry with small or no leaves, water-resistant cuticles, and often spines to deter herbivory.

Some annual plants germinate, bloom, and die in the course of a few weeks after rainfall while other long-lived plants survive for years and have deep root systems able to tap underground moisture.

Animals need to keep cool and find enough food and water to survive. Many are nocturnal and stay in the shade or underground during the heat of the day.

They tend to be efficient at conserving water, extracting most of their needs from their food, and concentrating their urine. Some animals remain in a state of dormancy for long periods, ready to become active again when the rare rains fall.

They then reproduce rapidly while conditions are favorable before returning to dormancy. People have struggled to live in deserts and the surrounding semi-arid lands for millennia.

Nomads have moved their flocks and herds to wherever grazing is available and oases have provided opportunities for a more settled way of life.

The cultivation of semi-arid regions encourages the erosion of soil and is one of the causes of increased desertification. Desert farming is possible with the aid of irrigation and the Imperial Valley in California provides an example of how previously barren land can be made productive by the import of water from an outside source.

Many trade routes have been forged across deserts, especially across the Sahara Desert, with caravans of camels carrying salt, gold, ivory, and other goods. Some mineral extraction also takes place in deserts and the uninterrupted sunlight gives the potential for the capture of large quantities of solar energy.

Desert Plants

Desert plants have two main adaptations- the ability to collect and store water, and features that reduce water loss. Plants that have adapted by altering their physical structure are called xerophytes.

Xerophytes, such as cacti, usually have special ways of storing and conserving water. They often have few or no leaves, which reduces water loss.

Phraetophytes are plants that have adapted to living in the desert by growing very long roots, allowing them to get their moisture deep within the earth, at or near the water table.

Below are a few of the plants you will see in the desert. Interesting facts are also given for each plant

Cactus: The cactus family is one of the most easily recognized plant families in the world. Their beautiful blossoms, thick stems, and unusual shapes attract thousands of people to the desert each year. Cacti show variations between the individual species.

They range from the three-inch fishhook cactus nestled in a rock crevice to the towering saguaro cactus which reaches heights of 30 to 40 feet. Cactus grow on rocky hillsides, alluvial fans, and in barren washes throughout the desert.

Cactus take advantage of the lightest rainfall by having roots close to the soil surface. The water is quickly collected by the roots and stored in thick, expandable stems for the long summer drought.

The fleshy stems of the barrel cactus are pleated like an accordion and shrink as moisture is used up. These pleats also channel water to the base of the plant during rain showers.

When water is no longer available in the summer, many desert shrubs drop their leaves and become dormant. Cactus continue to photosynthesize because they have fixed spines instead of leaves.

The green stems produce the plant’s food but lose less water than leaves because of their sunken pores and a waxy coating on the surface of the stem. The pores close during the head of the day and open at night to release a small amount of moisture.

 

WBBSE Solutions For Class 8 School Science Chapter 10 Biodiversity, Environmental Crisis and Conservation of Endangered Animals cactus.jpg

 

Joshua plants: The Joshua tree, the largest of the yuccas, grows only in the Mojave Desert. Natural stands of this picturesque, spike-leafed evergreen grow nowhere else in the world.

Its height varies from 15-40 feet with a diameter of 1-3 feet. They grow 2 to 3 inches a year, take 50 (2)to 60 years to mature, and can live 150 years. It is a large desert plant with spiky leaves.

It also has a fruit which is food for desert animals. The Joshua tree provides food and shelter for many desert animals.

 

WBBSE Solutions For Class 8 School Science Chapter 10 Biodiversity, Environmental Crisis and Conservation of Endangered Animals joshua plants.

 

Saguaro cactus: The Saguaro cactus, is composed of a tall, thick, fluted, columnar stem, 18 to 24 inches in diameter, often with several large branches (arms) curving upward.

The stem of the Saguaro Cactus stores all of its water. The stem is green Photosynthesis occurs in the top area of the stem instead of in the leaves.

This plant has another adaptation that is hidden from us. This is its large network of roots – that extend far away from its trunk. The roots collect water after rain.

Stored in the pleated expandable stem, the water keeps the saguaro alive until the next rain. Saguaro fruit is used in jam and woody skeletons are used in building materials.

The skin is smooth and waxy, and the trunk and stems have stout and 2-inch spines clustered on their ribs. When water is absorbed, the outer pulp of the Saguaro can expand like an accordion, increasing the diameter of the stem and in this way, can increase its weight by up to a ton.

 

WBBSE Solutions For Class 8 School Science Chapter 10 Biodiversity, Environmental Crisis and Conservation of Endangered Animals saguaro cactus

 

Mesquite plants: Mesquite trees are usually in most of their range they are the size of a shrub. Older trees can reach a height of 20 to 30 ft.

They have narrow, compound leaves 50 to 75 mm (2 to 3 inches) long that are sharply pointed. Mesquite is an extremely hardy, drought-tolerant plant because it can draw water from the water table through its long taproot (recorded at up to 190 ft in depth).

However, it can also use water in the upper part of the ground, depending upon availability. The tree can regenerate from a piece of root left in the soil. New growth of mesquite has tough, needle-sharp thorns up to 3 inches

 

WBBSE Solutions For Class 8 School Science Chapter 10 Biodiversity, Environmental Crisis and Conservation of Endangered Mesquite plants

 

Desert Animals

Lack of water creates a survival problem for all desert organisms, animals, and plants alike. But animals have an additional problem — they are more susceptible to extremes of temperature than plants.

Animals receive heat directly by radiation from the sun, and indirectly, by conduction from the substrate (rocks and soil) and convection from the air.

Among the thousands of desert animal species, there are almost as many remarkable behavioral and structural adaptations developed for avoiding excess heat.

Some interesting desert animals are-

Camel: A camel stands from 1.8 m to just over 2 meters tall at the shoulders, and weighs from 250 to 680 kilograms.

Its rope-like tail is over 50 centimeters long. Camels seem larger than they are because of their thick, woolly fur, which may be all shades of brown, from nearly white to almost black.

An Arabian camel’s fur is short and helps protect its body from heat. A Bactrian camel’s fur is longer. It may grow about 25 centimeters long on the animal’s head, neck, and humps.

Camels have many adaptations that allow them to live successfully in desert conditions. Deserts are hot and dry. Common adaptions are-

A camel can go a week or more without water, and they can last for several months without food. They can drink up to 32 gallons (46 liters) of water in one drinking session.

Camels store fat in the hump, not water. The fat can be metabolized for energy.

Unlike most mammals, a healthy camel’s body temperature fluctuates (changes) throughout the day from 34°C to 41.7°C (93°F-107°F.) This allows the camel to conserve water by not sweating as the environmental temperature rises.

  1. Camels’ feet are wide so they can walk on the sand more easily. Their huge feet help them to walk on sand without sinking into it.
  2. Camels have thick lips so they can eat the prickly desert plants without feeling pain.
  3. The color of their bodies helps them to blend into their environment.
  4. Camel’s ears are covered with hair, even on the inside. The hair helps keep out sand or dust that might blow into the animal’s ears.
  5. Winds blow sand all around, so a camel has long eyelashes. It has nostrils that can open and close.

WBBSE Solutions For Class 8 School Science Chapter 10 Biodiversity, Environmental Crisis and Conservation of Endangered Animals camels.jpg

 

Horned lizards: The numerous species of horned lizards, all members of the genus Phrynosoma, have very wide, flattened, toad-like bodies.

The tail is short but broad at the base. In most species, the back of the head and temples are crowned with a prominent row of sharp, pointed horns. The tail and sides are fringed with sharp spines.

To the uninitiated, their dragon-like appearance is quite formidable. The squat form and head armor has given rise to the name “horny toad,” “horned toad” and “horned lizards.” However, since there is a true toad with horns, it is best that we speak of this genus as the “horned lizards.”

WBBSE Solutions For Class 8 School Science Chapter 10 Biodiversity, Environmental Crisis and Conservation of Endangered Animals Horned lizards.

 

Their colors are pleasing. The back and head are soft desert gray. The markings are in pastel shades of tan, brown, red, or yellow.

The underparts are pale, yellowish-gray. The overall colors are generally close to the predominant color of the soil. Color changes from light to dark (or reverse) can occur within a few minutes.

Rattlesnake: Rattlesnakes are easily recognized animals. There are 32 known species of rattlesnakes that live in North and South America.

Rattlesnakes are mainly associated with arid and desert rocky areas, but they can be also found in forests, prairies, and swampy habitats. Rattlesnakes are known for their relatively heavy bodies and diamond-shaped heads.

They are considered to be the newest or most recently evolved snakes in the world. Rattlesnakes have either a rattle or a partial rattle made of interlocking rings, or segments of keratin,

The same material our fingernails are made of When vibrated, the rattle creates a hissing sound that warns off potential predators. It is an extremely effective and highly evolved predator-avoidance system.

Another rattlesnake characteristic is the “pit” on each side of the head, which is a heat-sensitive organ for locating prey.

 

WBBSE Solutions For Class 8 School Science Chapter 10 Biodiversity, Environmental Crisis and Conservation of Endangered Animals rattele snake

 

Gerbil: The gerbil (kangaroo rat) is a small rodent, similar in many ways to the mouse and the hamster. Gerbils have long tails like a mouse which the gerbil is able to shed should the tail get trapped.

This self-defense mechanism allows the gerbil to escape predators, leaving them with just a tail. Gerbils have sharp claws which the gerbils use to burrow their way into the sandy grounds of the temperatures may get very cold at night.

Gerbils tend to stay inside their burrows during the hottest parts of the day and the coolest parts of the night. The temperatures within the burrow are more moderate than the temperatures outside.

 

WBBSE Solutions For Class 8 School Science Chapter 10 Biodiversity, Environmental Crisis and Conservation of Endangered Animals gerbil.jpg

Some other desert animals are-

  1. Desert Bighorn Sheep,
  2. Scorpion,
  3. Ostriches,
  4. Addax Antelope.

Thar, the great Indian desert also called the ocean of sand is home to many species of birds, reptiles, and wild animals. The various desert animals and plants are adapted to survive in adverse climatic conditions.

The animals of the great thar desert include numerous species of reptiles, desert scorpions, mongoose, red foxes, chinkara, and falcons.

Indian Bustard, Blackbuck, and wild cat are a few species that are fast vanishing in other parts of India but can be spotted here. The ship of the desert, Camels are the first animal that comes to mind when talking about a wildlife safari in the desert.

Some people grow crops like bajra, jawar, wheat, and mustard seeds. There are also many industries (textiles, sugar, cement, fertilizers, etc.) and mines (lead, zinc, iron ore, etc.) that provide people of this region with means of livelihood.

Handicrafts and jewelry made in Rajasthan are sold in many parts of India and the world. The women of Rajasthan wear colorful with an odhani or chunni.

The men wear dhoti-kurta with turbans to protect themselves from the harsh sun. People in the desert travel on camels or carts pulled by camels.

The camel is a very useful animal in the desert. Most houses in the desert region have flat roofs and small windows. The walls are thick to keep the heat out and let the house remain cool.

The main festivals of Rajasthan are the Desert Festival, Gangaur, Teej, Holi, Dussehra, Diwali, and Id. Jaipur is the capital of Rajasthan.

Question 22. Write briefly about cactus as food.
Answer:

Cactus as a food: Edible cactus is also known as nopales. This vegetable is popular in Mexico and other Central American countries, parts of Europe, the Middle East, India, North Africa, and Australia.

Its popularity is increasing in the United States. Edible cactus is characterized by its fleshy oval leaves (typically called pads or paddles) of the nopal (prickly pear) cactus.

With a soft but crunchy texture that also becomes a bit sticky when cooked, edible cactus tastes similar to a slightly tart green bean, asparagus, or green pepper. Cactus pads contain beta carotene, iron, and some B vitamins, and are good sources of both vitamin C and calcium

Question 23. What is a rattle of a rattlesnake?
Answer:

A Rattle Of A Rattlesnake:-

The rattle is found at the tip of the rattlesnake’s tail. The snake uses the rattle to warn potential aggressors to back off or to distract prey.

The famous rattle noise comes from the sound created when hollow and bony doughnut-like segments in the rattle bang together. Rattles are segments of keratin that fit loosely inside one another at the end of the snake’s tail.

These segments knock against each other to produce a buzzing sound when the snake holds its tail vertically and vibrates the rattle. Each time a rattlesnake sheds its skin it adds another segment to the rattle.

Question 24. What are Polar Regions? Write about the adaptations of polar organisms.
Answer:

Life in Polar Region

The Polar Regions are the most inhospitable places on the planet. For centuries humankind has tried and often failed to reach and study both the Arctic and Antarctic Circles, losing life and limb in the process.

Polar habitats are located at the very top and very bottom of the earth. They are cold, and windy and have a lot of snow and ice.

It’s even too cold for trees to grow. Tundra takes up a lot of the area of polar habitats. It’s the only place where any plants can grow, but the ground only thaws just enough for short grasses and moss-tree roots can’t go as far down into the ground as they need to because it’s frozen.

Animals who live in polar regions have adapted by having thick fur or feathers, and hunting fish or each other rather than relying on plants.

Question 25. How is a climatic change affecting Antarctic penguins?
Answer:

How is a climatic change affecting Antarctic penguins?

The Antarctic continent is warming as a whole, but the Antarctic Peninsula—the northernmost region that juts out towards South America—is warming faster than any other place in the Southern Hemisphere.

Because of this rapid warming, sea ice along the western Antarctic Peninsula is shrinking in size, and the sea-ice season is shorter.

The loss of sea ice is harming Emperor penguin chicks and adults. Emperor penguins rear their chicks on land-locked sea ice.

When sea ice breaks up before their chicks have matured and grown their waterproof feathers, chicks that are swept into the ocean are likely to die.

For adults, the loss of sea ice can lead to lower food availability, which can result in increased mortality.

Question 26. Write about the effect of global warming in Antarctica.
Answer:

The main threats facing Antarctica

Global warming —This results in a loss of sea ice and land-based ice, which is the greatest long-term threat to the region.

Already some ice shelves have collapsed and ice slopes and glaciers have retreated. Oceanic acidification (from extra dissolved carbon dioxide) is already leading to the loss of some marine snails thought to have a significant part to play in the oceanic carbon cycle.

The breeding Oil spills from tourist ships and fishing boats have affected animals in Antarctica. Because of the oil spills, life in Antarctica will get sick or die.

The people in Antarctica have been dropping rubbish and pollutants. This has affected animals in Antarctica.
Eco-tourists traveling to Antarctica are adding to global warming which is melting the polar ice caps, new research has found.

Both science and tourism have the potential to damage the very qualities that draw them to Antarctica. The main threats facing Antarctica populations and ranges of some penguin species have already been altered.

Increased tourism — with the accompanying pollutants that accompany ships and aircraft, the possibility of oil spills, and the effects of lots of people and infrastructure on wildlife and the wider environment.

Pollution — CFCs and other ozone depleters are responsible for the ozone hole that has appeared over Antarctica for over 30 years, chemicals produced thousands of miles away are found in Antarctic ice and in the bodies of wildlife.

Discarded equipment, chemicals, and oil can degrade the landscape. Fishing nets, plastic, lines, hooks, etc. carried by sea can result in great suffering or loss of life by birds, fish, and marine mammals.

Exploration and exploitation of mineral reserves, oil, and gas- Not currently economically viable, but as the need becomes greater and as technology advances, this will become an increasing threat.

The Antarctic Treaty bans all mining and mineral exploitation indefinitely, though this comes up for review in 2048 (in other words, it isn’t really banned indefinitely at all).

Direct impacts associated with the development of infrastructure for scientific bases and programs- The construction of buildings and related facilities such as roads, fuel storage, runways, etc. are damaging the natural ecosystems of the entire area.

Question 27. What is IUCN? State its role in the conservation of biodiversity.
Answer:

IUCN and its role in conservation

The International Union for Conservation of Nature and Natural Resources (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources.

It is involved in data gathering and analysis, research, field projects, advocacy, lobbying, and education. lUCN’s mission is to “influence, encourage and assist societies throughout the world to conserve nature and to ensure that any use of natural resources is equitable and ecologically sustainable.”

Question 28. What is the ecological importance of vultures?
Answer:

The Ecological Importance Of Vultures:-

For centuries, vultures have been silently performing a very important task of scavenging in the cycle of nature. They are Nature’s Custodians of Cleanliness.

They dispose of the carcasses of dead animals, both wild and domestic, along with other lesser scavengers such as jackals, hyenas, dogs, crows, and kites. As a result, pathogenic organisms do not get the chance to spread an epidemic.

Question 29. Write about the measures to conserve Ganga Dolphins.
Answer:

Conservation: India has declared Ganga Dolphin as the National Aquatic Animal of India. The Ganges River Dolphin is a rare species of dolphin found only in India and neighboring countries.

There are various conservation works going on in the Sanctuary Areas to protect the National Aquatic Animal of India. Vikramshila Gangetic dolphin sanctuary is the only protected area for the endangered Gangetic dolphins in Asia.

It is located in the Bhagalpur District of Bihar, India. Only a few hundred dolphins remain in India, of which half are found here.

WWF-India and Aaranyak an NGO have been working closely with various government departments to protect these blind river Dolphins of India.

Question 30. Write briefly about the social life of the Indian rhinoceros.
Answer:

Social Life Of The Indian Rhinoceros:-

The Indian rhinoceros forms a variety of social groupings. Adult males are generally solitary, except for mating and fighting.

Adult females are largely solitary when they are without calves. Mothers will stay close to their calves for up to four years after their birth, sometimes allowing an older calf to continue to accompany her once a newborn calf arrives.

Sub-adult males and females form consistent groupings, as well. Groups of two or three young males will often form on the edge of the home ranges of dominant males, presumably for protection in numbers.

 

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