Habitat and Adaptation

In a cactus plant, photosynthesis occurs in

1. Leaves
2. Spines
3. Modified roots
4. Modified stem

Answer

Modified stem

Reason — In the cactus, leaves are modified into spines. The green leaf like structure is modified into stem, which contains chlorophyll. Thus, the modified stem is the centre of photosynthesis in the cactus plants instead of leaves. The leaves are absent.

The animals such as birds have

1. Light bones with air cavities
2. Solid heavy bones
3. Heavy pointed bones
4. No bones

Answer

Light bones with air cavities

Reason — Light bones with air cavities keeps the body of birds light and thus help in flight.
Solid heavy bones would make flying difficult. Heavy pointed bones are not a biological feature of birds. Birds are vertebrates and have a skeleton.

The biotic components of the environment includes

1. Green plants
2. Animals
3. Decomposers
4. All of these

Answer

All of these

Reason — The living organisms such as plants, animals and decomposers are the biotic components of the environment.

The presence of hollow plant stems is a characteristic of

1. Desert plants
2. Aquatic plants
3. Mountainous trees
4. None of these

Answer

Aquatic plants

Reason — The stem of aquatic plant is long, hollow, light and grows well up to the water surface.
Desert plants have thick stems for water storage, not hollow stems. Mountainous trees are adapted to cold and wind with woody, solid trunks and so do not have hollow stems.

Slow breathing is the characteristic of

1. Desert Animals
2. Aquatic Animals
3. Aerial Animals
4. Land Animals

Answer

Desert Animals

Reason — Slow breathing is the characteristic of desert animals because certain amount of moisture is always lost due to evaporation in the respiratory passage during breathing.
Aquatic animals breathe using gills or lungs adapted for water and do not need to slow their breathing to save water. Aerial animals (birds) need a rapid supply of oxygen for the energy demands of flight, so their breathing is fast rather than slow. Not all land animals live in water-scarce conditions, so slow breathing is not their general characteristic.

Diversity of organisms is found in different habitats because of different adaptations for

1. Average temperature
2. Soil type
3. Annual precipitation
4. All of these

Answer

All of these

Reason — Organisms adapt to different abiotic factors such as average temperature, soil and annual precipitation in different ways. That is why a diversity of organisms is present in different habitats.

Which of the following is an aquatic plant ?

1. Rice
2. Mango
3. Vallisneria
4. Cactus

Answer

Vallisneria

Reason — Vallisneria is an aquatic plant commonly used in setting up an aquarium. It remains submerged in the water.
Rice grows in water-logged fields but is not a fully aquatic plant. Mango is a terrestrial fruit tree. Cactus is a desert plant adapted to dry conditions.

Which of the following categories of animals have a streamlined body shape ?

1. Birds and Reptiles
2. Fish and Amphibians
3. Fish and Birds
4. Birds and Mammals

Answer

Fish and Birds

Reason — A streamlined body shape is designed to minimize resistance when moving through a fluid like water or air, and both fish and birds have evolved to have this shape for efficient movement.
The other pairs are wrong because each includes at least one group that is not streamlined: reptiles, amphibians and most mammals do not have a streamlined body, as they are not adapted for fast, continuous movement through water or air.

Gill cover is technically termed as :

1. Exoskeleton
2. Operculum
3. Flippers
4. None of these

Answer

Operculum

Reason — Gill cover is technically termed as Operculum.
Exoskeleton is outer protective skeleton found in insects and some other animals. Flippers is limb-like structures used for swimming in animals like whales and seals.

The animal which has a thick skin covered with fur is :

1. Whale
2. Cat
3. Camel
4. Yak

Answer

Yak

Reason — Yak has thick skin covered with fur to protect it from cold.
Whale has a thick layer of blubber, not fur. Cat has fur but not thick enough for extreme cold survival like yak. Camel has thick skin but very sparse hair, adapted for deserts.

Assertion: Adaptations are the changes in the body or behaviour of an organism that enable it to survive comfortably and successfully in a habitat.

Reason: Adaptations occur according to the climatic conditions of the surroundings, specific requirements of the body and habitat of the organisms.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

Both A and R are true and R is the correct explanation of A.

Reason — A is true as adaptation refers to special body features or behaviours that help organisms survive and reproduce successfully in their habitat.
R is true as adaptations develop according to climate, habitat, availability of food and water.

Therefore, Both A and R are true and R is the correct explanation of A is the correct option.

Assertion: Biotic factors of the environment include plants, animals and humans whereas soil, water, air and sunlight belong to abiotic factors.

Reason: All the living and non-living components of the environment are classified as biotic and abiotic factors which are inter-related to each other. They are also dependent on each other for various purposes.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

Both A and R are true but R is not the correct explanation of A.

Reason — A is true as biotic factors include living organisms like plants, animals, and humans. Abiotic factors include non-living things like soil, water, air, and sunlight.
R is true as Environment has living (biotic) and non-living (abiotic) components. They are interrelated and depend on each other.

Therefore, Both A and R are true but R is not the correct explanation of A is the correct option.

Assertion: The feathers on the tail of a bird help to slow down its speed and also help in steering (changing direction) while flying.

Reason: The strong breast muscles of the bird help in the movement of wings, regulate speed and steering.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

Both A and R are true but R is not the correct explanation of A.

Reason — A is true as The feathers on a bird’s tail (called tail feathers or rectrices) help in steering, balancing, slowing down while landing.
R is true as birds have strong breast muscles that move the wings up and down and help in flying and generating thrust.

Therefore, Both A and R are true but R is not the correct explanation of A is the correct option.

Assertion: An event of distribution of seeds far away from the parent plant is significant to spread in large area/ different climatic conditions and to develop some new, better adaptations.

Reason: Dispersal of seeds avoids over-crowding, otherwise all the seeds will get insufficient space, water and nutrients.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

Both A and R are true and R is the correct explanation of A.

Reason — A is true as seed dispersal is the process of spreading seeds away from the parent plant. It's important because it helps plants spread to different areas and climates and increases chances of survival and adaptation.
R is true as seed dispersal prevents overcrowding and competition for space, water, sunlight, and nutrients.

Therefore, Both A and R are true and R is the correct explanation of A is the correct option.

Fill in the blanks with a suitable word :

(i) In birds, ............... are modified into wings.
(ii) The mountain goat has strong ............... for running up on rocky slopes of the mountains.
(iii) The hump of a camel is full of ............... which serves as the reserved food.
(iv) Whales are ............... mammals.
(v) The kind of flowers in which pollination occurs with the help of water is termed as ............... flower.

Answer

(i) forelimbs
(ii) hooves
(iii) fat
(iv) marine
(v) hydrophilous

Write true or false against the following statements. Rewrite and correct the false statements :

(i) Dorsal and ventral fins of a fish are paired fins.
(ii) Fishes breathe by means of nostrils.
(iii) A camel urinates very less and its urine is comparatively thicker.
(iv) The leaves of water lily are reduced in the form of spines to reduce transpiration.
(v) The claws of a bird help in steering (changing direction).

Answer

(i) False
Correct Statement — Dorsal and ventral fins of a fish are unpaired fins.

(ii) False
Correct Statement — Fishes breathe by means of gills.

(iii) True

(iv) False
Correct Statement — The leaves of cacti are reduced in the form of spines to reduce transpiration.

(v) False
Correct Statement — The tail feathers of a bird helps in steering (changing direction).

Match the terms given in column A with those of column B:

Answer

List any four abiotic factors which affect different living beings.

Answer

Four abiotic factors affecting different living beings are:

1. Soil
2. Air
3. Water
4. Temperature

Define the following: Habitat, Adaptation.

Answer

Habitat — The natural home of an organism and its immediate surroundings is called its habitat. The habitat of any living creature should be a place where it can find shelter, food, water and suitable conditions for breeding.

Adaptation — Adaptation is the development of any structure or function in an organism which makes it more efficient for survival in a particular environment or habitat, i.e. adaptations are the changes in the body or behavior of an organism that enables it to survive comfortably and successfully in a habitat.

Briefly explain the term "Habitat".

Answer

The natural home of an organism and its immediate surroundings is called its Habitat. The habitat of any living creature should be a place where it can find shelter, food, water and suitable conditions for breeding. The special feature of habitat is that it includes all the physical characteristics around it (air, water, temperature, etc.) along with the surrounding plants and animals. There are three types of habitat

1. Aquatic habitat
2. Terrestrial habitat
3. Aerial habitat

Give two adaptations in animals found in the mountain habitat.

Answer

The two adaptations in animals found in the mountain habitat are:

1. The oxygen content in the mountain air is thin. So the blood of most of these animals contains more red blood cells. This helps them to breathe in sufficient oxygen even when air pressure is low.
2. Some animals hibernate or go for a long winter sleep when the temperatures are very low. In this way, they conserve their energy and survive the winter without food. Frogs and hedgehogs are some animals which hibernate.

How is a whale similar to a fish in adaptation to life in water? Explain any two features.

Answer

Two features of whales similar to a fish in adaptation to life in water are:

1. Like fish, the huge body of whale is also streamlined in a spindle shape.
2. Its front legs are modified into paddles or flippers for kicking water and hind limbs are absent.

List the environmental factors that influence a habitat.

Answer

The environmental factors that influence a habitat are:

1. Air
2. Water
3. Climatic condition
4. Temperature
5. Plant and Animal

Name any three types of terrestrial habitat.

Answer

Three types of terrestrial habitats are:

1. Desert habitat
2. Mountain habitat
3. Polar habitat

Name two types of terrestrial habitats with low temperatures.

Answer

Two types of terrestrial habitats with low temperatures are:

1. Polar habitat
2. Mountain habitat

Complete the table given below. Write down two points in each given column.

Answer

State the "water saving methods" in a camel.

Answer

The water saving methods in a camel are:

1. Little and thick urine — When deprived of water, the camel passes out very little urine and it is quite thick.
2. Semi-dry faeces — The dung passed out is quite dry.
3. Perspires very little — The camel can tolerate high outside temperature up to 40°C to 45°C as its own body temperature can go up to 41°-42°C and therefore the need to perspire is reduced.
4. Slow breathing — Certain amount of moisture is always lost due to evaporation in the respiratory passages during breathing. Slower the rate of breathing, lesser the loss of water as water vapour in the air breathed out.
5. Water "storage" in muscles — The camel's muscles can withstand the shortage of water and can shrink considerably. Once the water is available, the camel can drink sufficient water and the muscles swell up.
6. Water from the "fat" of the hump — While starving, the fat is oxidized to yield energy as well as water.

Name the following :
(i) Three major categories of habitats
(ii) Four types of terrestrial habitats
(iii) Two components of the environment
(iv) Two categories of dispersing agents
(v) Three plants found in the mountainous regions

Answer

(i) Aquatic habitat, Terrestrial habitat, and Aerial habitat
(ii) Desert habitat, Mountain habitat, Polar habitat, Forests and grasslands
(iii) Biotic components and Abiotic components
(iv) Natural agents and Animals
(v) Pine, Fir, Cedar

Define the terms given below :

(i) Habitat
(ii) Adaptation
(iii) Abiotic factors
(iv) Biotic factors
(v) Seed dispersal

Answer

(i) Habitat — The natural home of an organism and its immediate surroundings is called its habitat.

(ii) Adaptation — Adaptation is the development of any structure or function in an organism which makes it more efficient for survival in a particular environment or habitat, i.e. adaptations are the changes in the body or behavior of an organism that enables it to survive comfortably and successfully in a habitat.

(iii) Abiotic factors — Abiotic factors are the non-living, physical, and chemical components of an ecosystem. They include various non-living things, such as soil, rocks, air, water, temperature, etc.

(iv) Biotic factors — Biotic factors are the living components of an ecosystem. They include all organisms, like plants, animals, fungi, bacteria, and other microorganisms.

(v) Seed dispersal — Seed dispersal is the process by which plant seeds are transported away from the parent plant to a new location, allowing them to germinate and grow into new plants.

Write one important function of the following :
(i) Fins
(ii) Gills
(iii) Swim bladder of a fish
(iv) Hump of a camel
(v) Streamlined body of a bird

Answer

(i) A fish swims with the help of fins.

(ii) The gills are the breathing organs of fishes that help them breathe.

(iii) Swim bladder of a fish helps in maintaining buoyancy and the fish can rise upward or sink downward by increasing or decreasing the amount of gas in the bladder.

(iv) The hump of the camel is full of fat which serves as the reserved food. The camel can remain without food for several days and during that period, the fat in the hump serves as a source of energy.

(v) Streamlined body of a bird helps to encounter least resistance while flying in the air.

Choose the odd one and give reason in support of your answer :

(i) Neem, Pine, Fir, Cedar
(ii) Reindeer, Deer, Polar bears, Penguins
(iii) Scales, Fins, Fur, Gills
(iv) Seeds of — Cotton, Poppy, Drumstick, Mango
(v) Water lily, Lotus, Cactus, Vallisneria

Answer

(i) Odd one — Neem
Reason — Neem is a plain region tree, while Pine, Fir, and Cedar are found in mountainous regions.

(ii) Odd one — Deer
Reason — Deer is found in forests or plains, while Reindeer, Polar bears, and Penguins are adapted to polar regions.

(iii) Odd one — Fur
Reason — Fur is a feature of land mammals, whereas Scales, Fins, and Gills are adaptations of aquatic animals.

(iv) Odd one — Mango
Reason — Mango seeds are dispersed by animals, while Cotton, Poppy, and Drumstick seeds are dispersed by wind.

(v) Odd one — Cactus
Reason — Cactus is a desert plant, while the others are Aquatic plants.

Describe any two adaptations seen in desert plants.

Answer

The two main adaptations seen in desert plants are

1. Most cacti desert plants have spines instead of leaves. Leaves would lose water through transpiration.

2. Photosynthesis is carried out by the thick green stem.

Describe the aerial adaptations in birds.

Answer

Various aerial adaptations found in birds are:

1. Body shape — The body of birds is streamlined. Necks stretched forward with the head pointed in front and a narrowed tail at the end provide them a sleek shape. The body surface is smooth to minimize resistance against air.
2. Wings — The forelimbs are modified into wings. The whole length of the forelimb carries long flight feathers.
3. Steering and brakes — The feathers on the tail help to slow down the speed and also help in steering (changing direction).
4. Wing muscles — These are the strong, active and enlarged breast muscles which support and help in the movement of wings.
5. Cutting down the body weight — Except for the most necessary bulky heavy wing muscles, the rest of the bird's body tends to be light to facilitate flight.
   1. Bones have air cavities.
   2. Much less water is required in the body. The birds excrete solid urine (formed of uric acid instead of urea which otherwise requires much water to be excreted out).

Differentiate between an aquatic habitat and a terrestrial habitat.

Answer

Difference between an Aquatic habitat and Terrestrial habitat:

Describe how pollination occurs in Vallisneria?

Answer

Vallisneria is well-adapted for cross pollination. It is a dioecious plant where male and female plants are separate. Pollination occurs with the help of water and such flowers are called hydrophilous. The male flowers are very small and on maturity, get detached. They float on the surface of water. The female flowers remain afloat on long stalks. Free floating male flowers pollinate the female flowers on the surface of water.

Ankur and his classmates went on a virtual field trip to the Great Himalayas, the highest mountain range in the country. As they travelled up the mountain, they noticed how different animals adapt to the cold, rocky environment. Mountain habitats are extremely cold and windy, and for several months they remain covered in snow. Despite the cold, a wide variety of plants and animals survive there.
Answer the following questions:

(i) Name two plants that Ankur and his classmates could observe at high mountains.

(ii) What is the technical term for the ability of organisms to survive in any habitat by making specific changes in their bodies?

(iii) Give two examples of mountain animals.

(iv) What changes occur in the blood of mountain animals to help them survive in low-oxygen conditions?

(v) What is the advantage of hibernation among these animals?

Answer

(i) Two plants found in high mountain regions are pine and cedar.

(ii) The technical term for the ability of organisms to survive in any habitat by making specific changes in their bodies is called as adaptation.

(iii) Two examples of mountain animals are yak and mountain goat.

(iv) The blood of most of these mountain animals contains more red blood cells. This helps them to breathe in sufficient oxygen even when the air pressure is low.

(v) The advantage of hibernation among these animals is that they hibernate when the temperatures are very low. In this way, they conserve their energy and survive the winter without food.