Chapter: 08. Adaptation
A. Multiple Choice Questions
Animals that undergo hibernation during winter Light and hollow bones are found in Swollen petiole is present in Biotic components of a habitat are © Both animals and plants Which of the following is not a xeric adaptation in xerophytes Feet have cloven hoofs in Tail feathers in birds and caudal fin in fish act as (b) Rudder for changing the direction and speed B. Assertion-Reason Type Questions
Assertion [A]: Deserts are dry, receiving very less or no rain round the year.
Reason [R]: Sparce desert life indicates less fertile soil. © Assertion [A] is true but Reason [R] is false. Assertion [A]: Aquatic plants do not need water to survive.
Reason [R]: Free-floating plants have air filled spaces between their cells. (d) Assertion [A] is false but Reason [R] is true. Assertion [A]: Fish have gills to get oxygen in water.
Reason [R]: Gill filaments have fine network for the flow of water. © Assertion [A] is true but Reason [R] is false. C. Fill in the blanks with suitable words.
Animals, plants and microorganisms represent _____ component of the habitat. ______ is a floating aquatic plant. Leaves in xerophytes are modified into _____ . _____ is called ship of the desert. Camel
Pine and fir trees are found in habitat. D. Give one word for the following.
Animals adapted to fly in air The place where an animal or plant live and breed Structures that help fish in swimming Organs that are used by fish for exchange of gases (O2 and CO2) in water Habitat that provides extreme cold condition, thin air and low oxygen concentration Plants that have succulent green stem with spines Plants that live in water Trees that do not lose or shed leaves in winter Trees that have needle-shaped leaves and conelike appearance E. Give main function of each of the following.
Waxy covering on the surface of leaves in hydrophytes Prevents the leaves from rotting in water. Pushes the body forward and functions like a rudder, helping in changing the direction during swimming. Feathers on the body of birds Keep the body warm and light; feathers on forelimbs help in flying, and on tail help in steering and as a rudder. Help it to walk on hot and slippery sand without sinking. F. Give reasons for the following.
Stem of cactus plant is thick and spongy. The stem of a cactus plant is thick and spongy to store water, as cacti live in deserts where water is scarce. It also becomes green to carry out photosynthesis, taking over the function of leaves. The seeds of Maple and Drumstick have parachute-like structure. The seeds of Maple and Drumstick have wings (parachute-like structure) to help them in floating in the air for long distances, facilitating wind dispersal. In floating plants roots are reduced and stem is thin and flexible. In floating plants, roots are reduced because they do not need to absorb water and nutrients from the soil, as they are directly surrounded by water. The stem is thin and flexible to allow them to sway with water currents and remain buoyant on the surface. In birds bones are light and hollow, filled with air cavities. In birds, bones are light and hollow, filled with air cavities (pneumatic bones), to reduce overall body weight, which is essential for flight. They are also fused to form a rigid yet light frame for flight muscle attachment. Mountain goats have double layers of woolly coat. Mountain goats have double layers of woolly coat to protect them against the extreme cold temperatures and high-speed winds prevalent in their mountain habitat. G. Encircle the odd one out. Give reasons for your choice.
Air bladder, gills, hollow bones, scales Hollow bones. Reason: Air bladder, gills, and scales are adaptations found in aquatic animals (fishes), while hollow bones are an adaptation found in aerial animals (birds) for flight. Eichhornia, Hydrilla, Lotus, Lily Hydrilla. Reason: Eichhornia, Lotus, and Lily are examples of floating or fixed-floating aquatic plants, while Hydrilla is an example of a submerged aquatic plant. Needle-like leaves, ribbon-like leaves, plate-like leaves, strap-like leaves Plate-like leaves. Reason: Needle-like, ribbon-like, and strap-like leaves are specific adaptive shapes mentioned for plants in different habitats (needle for mountains, ribbon/strap for submerged aquatic), whereas “plate-like” is not explicitly mentioned as a distinct adaptive leaf shape in the context of the chapter’s examples. Wings, hollow bones, feathers, fur on the body Fur on the body. Reason: Wings, hollow bones, and feathers are all aerial adaptations specifically found in birds for flight, whereas fur on the body is an adaptation found in mammals (e.g., mountain animals) for insulation or protection, not directly for flight. H. Match the columns.
I. Answer these questions. Define the term habitat. Name its types. Habitat: The place where an organism, i.e., plant or animal lives. Types of Habitats: Aquatic habitat, Terrestrial habitat, Aerial habitat. Name any two aquatic adaptations common for fish and whale. Streamlined body shape for easy movement through water. Fins (or flippers/tails in whales) for propulsion and steering. Give two adaptations in desert plants for conserving water. Succulent and spongy stem: To store water, and it also carries out photosynthesis. Leaves reduced to spines: To minimize water loss through transpiration and protect against herbivores. Thick and waxy coating on stem: To prevent water loss by evaporation. Write main adaptations in fir and pine trees for mountain life. Cone-shaped appearance: Helps them bear harsh wind and prevents them from being knocked down by heavy snow. Needle-like leaves with waxy coating: To prevent water loss and help snow slide down easily. Branches droop downward: To shed off excess snow. Name the types of terrestrial habitats. Desert habitat, Mountain habitat, Polar habitat, Forest and grassland habitats. Differentiate between desert and mountain habitats.
Name the structures that help birds to fly. Wings (modified forelimbs), streamlined body shape, tail feathers, feathers covering the body, enlarged breast/flight muscles, air sacs, and pneumatic (hollow) bones. What is the use of lateral line system for fish. The lateral-line system in fish consists of sense organs that can detect changes in the pressure of water currents, helping them navigate and detect predators or prey. J. Diagram-based Questions
Given below is the picture of a camel. Name the structures marked 1-5 and give reasons for the modification in them. Hump: Stores food in the form of fat, allowing the camel to survive without food for long periods in the desert. Eyes (with long eyelashes): Long eyelashes protect the eyes from dust and sand during duststorms. Legs/Feet (with padded feet): Large pads on the feet help it to walk on hot and slippery sand without sinking. Nostrils (with flaps): Nostrils have flaps that can close during a duststorm, preventing sand from entering. Complete the following table:
K. Case-based Questions
What is the shape of mountain plants? Mountain plants are usually tall, straight, and have a cone-shaped appearance (conifers). Why do they have thin and needle-like leaves? They have thin and needle-like leaves (with a waxy coating) to prevent water loss (transpiration) and to help snow slide down easily, preventing accumulation that could damage the branches. Why do mountain plants have ability to bend? Mountain plants are very supple and have a great ability to bend (their branches droop downward) to cope with harsh winds and heavy snowfall, allowing snow to shed off easily and preventing the branches from breaking. 
Answers to textbook exercises
I. Answer these questions.
