Detailed explanations in West Bengal Board Class 10 Life Science Book Solutions Chapter 4B Survival Strategies: Adaptation offer valuable context and analysis.
WBBSE Class 10 Life Science Chapter 4B Question Answer – Survival Strategies: Adaptation
Short Answer Type Questions : 2 Marks
Question 1.
What is an adaptation?
Answer:
An adaptation is a way an animal’s body helps it survive, or live in its environment. Camels have learned to adapt (or change) so that they can survive. Animals depend on their physical features to help them obtain food, keep safe, build homes, withstand weather and attract mates. These physical features are called physical adaptations. They make it possible for the animal to live in a particular place and in a particular way. Each adaptation has been produced by evolution. This means that the adaptation have developed over many generations.
Question 2.
Write the examples of the basic adaptations that help creatures survive.
Answer:
- Shape of a bird’s beak
- The number of fingers
- Colour of the fur
- The thickness or thinness of the fur
- The shape of the nose or ears
Question 3.
What is a habitat?
Answer:
The surroundings where plants and animals live, is called their habitat. A habitat provides suitable climatic conditions like food and shelter so that plants and animals can live there.
Question 4.
Do all organisms live in same habitat?
Answer:
No, all organisms do not live in same habitat. Some may share the habitat e.g. lion and deer. For example camel can live in deserts only while frogs can survive in fresh/rain water.
Question 5.
Are all forests habitats of tigers or lions?
Answer:
No all forests are not habitats of tigers and lions. For example, tigers can live in forests, which have thick forests, water (ponds and streams) and rich supply of food (e.g. deer).
Question 6.
How is cactus adapted to survive in a desert?
Answer:
Cactus survives in deserts due to following adaptations-It has flat green stem to store water and prepare food by photosynthesis. The stem is also covered with a thick waxy layer, which helps to retain water. It’s roots that go very deep into the soil for absorbing water. Leaves are turned into spines to prevent loss of water.
Question 7.
Name two plants and two animals of mountain regions.
Answer:
Animals-yak, snow leopard, mountain goat. Plants-pines, spruce, fir, cedar.
Question 8.
Give an example of a non-living thing, which shows any two characteristics of living things.
Answer:
A bus or a car which shows movement and consume energy (petrol).
Question 9.
Which of the non-living things listed below, were once part of a living thing? Butter, leather, soil, wool, electric bulb, cooking oil, salt, apple, rubber.
Answer:
Following are the things which were once part of living beings :
- Butter : Obtained from milk from dairy animals.
- Leather : From animal skin of buffaloes, cows etc.
- Wool : From hair of sheep and goat.
- Cooking oil : seeds of plants (e.g. mustard) or by grinding whole plant (e.g. olive).
- Apple : fruit from apple tree.
- Rubber : Latex of rubber tree. Following things were never part of living beings-soil, electric bulb, salt.
Question 10.
List the common characteristics of the living things.
Answer:
- Movement : All organisms show movement of one kind or another. Animals can move from one place to another. While plants also show movement e.g. bend towards light.
- Respiration : All organisms breathe and respire. They intake oxygen and release carbon dioxide.
- Feeding: They consume food to stay fit and grow.
- Growth and Death: All living beings grow i.e. with age they become larger in size and eventually die.
- Excretion : They remove waste material from their bodies.
- Reproduction : Living beings bear children.
- Stimuli or Sensitivity : All living beings react to external changes around them.
Question 11.
Give examples of animals which give birth to young ones.
Answer:
Humans, dogs, cats (mammals) give birth to young ones.
Question 12.
Give examples of terrestrial habitats.
Answer:
Deserts, forests, grasslands, coastal regions, mountain regions.
Question 13.
Give examples of aquatic habitats.
Answer:
Aquatic habitat includes rivers, ponds, lakes, ocean and swamps.
Question 14.
What is Acclimatization? How it is different from adaptation?
Answer:
The small adjustments by the body to overcome small changes in the surrounding atmosphere for a short period of time are called acclimatization. While in adaptation, it takes thousands of years for a living being to adapt to its habitat.
Question 15.
What are the two components of habitat?
Answer:
Biotic component, abiotic component.
Question 16.
Why is adaptation necessary? What does happen to those animals who do not adapt to the environment?
Answer:
Over thousands of years the abiotic factors of a region change. To survive animals and plants must adapt these changes. Those animals which cannot adapt these changes, die out, and only the adapted ones survive.
Question 17.
Do animals have the same kind of adaptations? Explain with an example.
Answer:
Animals adapt to different abiotic factors in different ways. For example, to survive in deserts, camels have long legs and padded feet. While desert animals like snakes and rats do not have long legs, but they stay in burrows deep in the sand and come out during night, when it is cooler.
Question 18.
What are the main morphological features of birds?
Answer:
Birds are animals with aerodynamic bodies covered with feathers, anterior limbs transformed into wings, pneumatic bones and horny (corneous) beaks.
Question 19.
In which habitat do birds live?
Answer:
Birds are terrestrial animals but the majority of them also explore the aerial environment by flying.
Question 20.
What adaptations for flight are present in birds?
Answer:
The features of birds that allow them to fly are-wings attached to a welldeveloped pectoral musculature, pneumatic bones, less accumulation of feces in the bowels due to the absence of the colon, the absence of a bladder (no urine storage), an aerodynamic body and lungs with specialized air sacs.
Question 21.
What are pneumatic bones?
Answer:
Birds have lightweight bones with internal spaces filled with air. These bones are called pneumatic bones. This feature reduces the density of body of the animal, facilitating flight.
Question 22.
How do camels adapt to their environment?
Answer:
Camels have many adaptations that allow them to live successfully in desert conditions. Deserts are hot and dry. Winds blow sand all around, so a camel has long eyelashes. It has nostrils that can open and close.
Question 23.
Why do camels have long eyelashes?
Answer:
The long eyelashes keep sand out of the camel’s eyes. Thick eyebrows shield the eyes from the desert sun.
Question 24.
Why does a camel have nostrils which can close?
Answer:
A camels nostrils can close so it doesn’t get sand up its nose.
Question 25.
What is swim bladder?
Answer:
The swim bladder, gas bladder, fish maw or air bladder is an internal gasfilled organ that contributes to the ability of a fish to control its buoyancy, and thus to stay at the current water depth without having to waste energy in swimming. The swim bladder is also of use as a stabilizing agent because in the upright position the centre of mass is below the centre of volume due to the dorsal position of the swim bladder. Another function of the swim bladder is the use as a resonating chamber to produce or receive sound.
Question 26.
What is Waggle dance?
Answer:
Waggle dance is a term used in beekeeping and ethology for a particular figure-eight dance of the honey bee. By performing this dance, successful foragers can share with other members of the colony, information about the direction and distance to patches of flowers yielding nectar and pollen to water sources or to new nest-site locations. A waggle dance with a very short waggle run used to be characterized as a distinct (round) recruitment dance.
Long Answer Type Questions : 5 Marks
Question 1.
Write the adaptive features of cactus plant.
Answer:
With desert conditions, conservation of water is extremely important to survive. Rainfall averages less than 10 inches per year. Consequently, plants have evolved ways to conserve or store water.
Among these adaptations are :
- Water storage tissues in stems or leaves.
- Leaves absent, reduced in size or short lived only when there is rain.
- Deep root systems to reach water or very wide root systems that efficiently capture water after a rainfall.
- Plants may produce a heavy thick cuticle of wax on leaves and stems to reduce water loss.
- Anatomically those plants that retain their leaves may show anatomical changes such as, reduced number of stomatas, sunken stomatas or “hairy” stomatas (protective trichomes that reduce water evaporation).
- Leaves may develop numerous trichomes (“hairs”) that shade the leaf and reduce water loss.
Question 2.
What are the physiological adaptations of a Sundry plants?
Answer:
They have a tolerance for salt water. Like xerophytes, halophytes also possess
Succulent leaves and stem
Thick walled and heavily cutinized epidermis
Hairy covering and mucilage cells.
Adaptations
- The leaves are reduced to small scaly structures (Casuarinas) or spines (Opuntia)
- The leaves are shed when water is scarce
- Water storage structures develop in the leaves
- They have a thick cuticle and a multiple layered epidermis
- They have sunken stomata
- They have long roots, which go in search of water
- The stem becomes green and takes over the function of photosynthesis where the leaves are absent/reduced/shed.
Question 3.
Write the name of air sacs of birds with their role.
Answer:
Most birds have 9 air sacs :
- one interclavicular sac
- two cervical sacs
- two anterior thoracic sacs
- two posterior thoracic sacs
- two abdominal sacs
Functionally, these 9 air sacs can be divided into anterior sacs (interclavicular, cervicals, & anterior thoracics) & posterior sacs (posterior thoracics & abdominals). Air sacs have very thin walls with few blood vessels. So, they do not play a direct role in gas exchange. Rather, they act as a ‘bellows’ to ventilate the lungs. The air sacs permit a unidirectional flow of air through the lungs. Unidirectional flow means that air moving through bird lungs is largely ‘fresh’ air and has higher oxygen content. In contrast, air flow is ‘bidirectional’ in mammals, moving back and forth into and out of the lungs. As a result, air coming into a mammal’s lungs is mixed with ‘old’ air (air that has been in the lungs for a while) and this ‘mixed air’ has less oxygen. So, in bird lungs, more oxygen is available to diffuse into the blood .
Question 4.
Write the adaptive features of camel.
Answer:
i. A camel can go a week or more without water, and they can last for several months without food.
ii. They can drink up to 32 gallon (46 litre) of water at one drinking session.
iii. Camels store fat in the hump, not water. The fat can be metabolised for energy.
iv. 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.
v. Camels feet are wide so they can walk on sand more easily. Their huge feet help them to walk on sand without sinking into it.
vi. Camels have thick lips so they can eat the prickly desert plants without feeling pain.
vii. The colour of their bodies helps them to blend into their environment.
viii. 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.
Question 5.
Where the swim bladder is seen? Write the structure and role of swim bladder.
Answer:
Swim bladders are only found in ray-finned fish. In the embryonic stages some species have lost the swim bladder again, mostly bottom dwellers like the weather fish. Other fishes like the Opah and the Pomfret use their pectoral fins to swim and balance the weight of the head to keep a horizontal position. The normally bottom dwelling sea robin can use their pectoral fins to produce lift while swimming. The cartilaginous fish (e,g. sharks and rays) and lobe-finned fish do not have swim bladders. They can control their depth only by swimming (using dynamic lift); others store fats or oils for the purpose.
Structure and function : The swim bladder normally consists of two gas-filled sacs located in the dorsal portion of the fish, although in a few primitive species, there is only a single sac. It has flexible walls that contract or expand according to the ambient pressure. The walls of the bladder contain very few blood vessels and are lined with guanine crystals, which make them impermeable to gases. By adjusting the gas pressure using the gas gland or oval window the fish can obtain neutral buoyancy and ascend and descend to a large range of depths. Due to the dorsal position it gives the fish lateral stability.
In physostomous swim bladders a connection is retained between the swim bladder and the gut. The pneumatic duct allowing the fish to fill up the swim bladder by “gulping” air and filling the swim bladder. Excess gas can be removed in a similar manner. In more derived varieties of fish, the physoclisti connection to the gastric duct is lost. In early life stages, fishes have to rise to the surface to fill up their swim bladders. However, in later stages the connection disappears and the gas gland has to introduce gas (usually oxygen) to the bladder to increase its volume and thus increase buoyancy.
In order to introduce gas into the bladder, the gas gland excretes lactic acid and produces carbon dioxide. The resulting acidity causes the haemoglobin of the blood to lose its oxygen (Root effect) which then diffuses partly into the swim bladder. The blood flowing back to the body first enters a rete mirabile where virtually all the excess carbon dioxide and oxygen produced in the gas gland diffuses back to the arteries supplying the gas gland. Thus a very high gas pressure of oxygen can be obtained, which can even account for the presence of gas in the swim bladders of deep sea.
The combination of gases in the bladder varies. In shallow water fish the ratios closely approximate that of the atmosphere, while deep sea fish tends to have higher percentages of oxygen.
Physoclist swim bladders have one important disadvantage-they prohibit fast rising, as the bladder would burst. Physostomes can “burp” out gas, though this complicates the process of re-submergence. In some fish, mainly fresh water species (e.g. common carp, wels catfish), the swim bladder is connected to the labyrinth of the inner ear by the Weberian apparatus, a bony structure derived from the vertebrae, which provides a precise sense of water pressure (and thus depth), and improves hearing.
Question 6.
Write about behavioural adaptation of Chimpanzee.
Answer:
Chimpanzees live in large multi-male and multi-female social groups, which are called communities. Within a community, the position of an individual and the influence the individual has on others dictates a definite social hierarchy. Chimpanzees live in a leaner hierarchy wherein more than one individual may be dominant enough to dominate other members of lower rank. Typically, a dominant male is referred to as the alpha male. The alpha male is the highest-ranking male that controls the group and maintains order during disputes. In chimpanzee society, the ‘dominant male’ sometimes is not the largest or strongest male but rather the most manipulative and political male that can influence the goings on within a group.
Chimpanzees make tools and use them to acquire foods and for social displays; they have sophisticated hunting strategies requiring cooperation, influence and rank. They are status conscious, manipulative and capable of deception. They can learn to use symbols and understand aspects of human language including some relational syntax, concepts of number and numerical sequence and they are capable of spontaneous planning for a future state or event.
Chimpanzees also engage in targeted hunting of lower-order primates, such as the red colobus and bush babies and use the meat from these kills as a “social tool” within their community.
Question 7.
Write about the language of bees and components of the dance language.
Answer:
When an experienced forager returns to the colony with a load of nectar or pollen that is sufficiently nutritious to warrant a return to the source, she performs a dance on the surface of the honeycomb to tell other foragers where the food is. The dancer “spells out” two items of information- distance and direction to the target food patch. Recruits then leave the hive to find the nectar or pollen. Distance and direction are presented in separate components of the dance.
Distance : When a food source is very close to the hive (less than 50 meters), a forager performs a round dance. She does so by running around in narrow circles, suddenly reversing direction to her original course. She may repeat the dance several times at the same location or move to another location on the comb to repeat it. After the round dance has ended, she often distributes food to the bees following her. A round dance, therefore, communicates distance (“close to the hive,” in this example), but not direction. Food sources that are at intermediate distances, between 50 and 150 meters from the hive, are described by the sickle dance. This dance is crescent-shaped and represents a transitional dance between the round dance and a waggle dance.
The waggle dance or wag-tail dance, is performed by bees foraging at food sources that are more than 150 meters from the hive. This dance, unlike the round dance, communicates both distance and direction. A bee that performs a waggle dance runs straight ahead for a short distance, returns in a semicircle to the starting point, runs again through the straight course, then makes a semicircle in the opposite direction to complete a full figure-eight circuit. While running the straightline course of the dance, the bee’s body, especially the abdomen, wags vigorously from side to side. This vibration of the body produces a tail-wagging motion. At the same time, the bee emits a buzzing . sound, produced by wing beats at a low audio frequency of 250 to 300 hertz or cycles per second. The buzzing occurs in pulse beats of about 20 milliseconds, delivered at a rate of about 30 per second.
Direction : The orientation of the dancing bee during the straight portion of her waggle dance indicates the location of the food source relative to the sun. The angle that the bee adopts, relative to vertical, represents the angle to the flowers relative to the direction of the sun outside the hive. In other words, the dancing bee transposes the solar angle into the gravitational angle. The figure gives three examples-a forager recruiting to a food source in the same direction as the sun will perform a dance with the waggle-run portion traveling directly upward on the honey comb. Conversely, if the food source is located directly away from the sun, the straight run will be performed vertically downward. If the food source is 60 degree to the left of the sun, the waggle run will be 60 degree to the left of vertical.
Because directional information is given relative to the sun’s position arid not to a compass direction, a forager’s dance for a particular resource will change during a day. This is because the sun’s position moves during the day.
Multiple Choice Questions : 1 Mark
Question 1.
Xerophytic plants are developed in
(a) Water
(b) Land
(c) Desert
(d) Ice
Answer:
(c) Desert
Question 2.
Phylloclade is
(a) Modified leaf
(b) Modified stem
(c) Root
(d) Flower
Answer:
(b) Modified stem
Question 3.
In cactus, leaves are modified into
(a) Tendril
(b) New plant
(c) Apines
(d) Stipule
Answer:
(c) Apines
Question 4.
The swim bladder is present in
(a) Chondrichthyes
(b) Rayed finned bony fish
(c) Aquatic mammals
(d) Scoliodon
Answer:
(b) Rayed finned bony fish
Question 5.
Number of air sacs in Pigeon is
(a) 8
(b) 9
(c) 10
(d) 7
Answer:
(b) 9
Question 6.
Trophic movement in breathing root is
(a) Positively phototrophic movement
(b) Negatively geotrophic movement
(c) Positively geotrophic movement
(d) Tacticative movement
Answer:
(b) Negatively geotrophic movement
Question 7.
In camel metabolic water comes from
(a) Protein
(b) Fat
(c) Carbohydrate
(d) Stored water in stomach
Answer:
(b) Fat
Question 8.
After parasitic attack, chimpanzee consumes
(a) Medicinal plant
(b) Medicines
(c) Water
(d) Protein
Answer:
(a) Medicinal plant
Question 9.
Waggling movement is seen in
(a) Chimpanzee
(b) Bees
(c) Human
(d) Cat
Answer:
(b) Bees
Question 10.
The hydrostatic organ is
(a) Air sac
(b) Swim bladder
(c) Spine
(d) Pneumatophore
Answer:
(b) Swim bladder
Very Short Answer Type Questions : 1 Mark
Question 1.
What is phylloclade?
Answer:
Modified stem.
Question 2.
In cactus, leaves are modified into which part?
Answer:
Leaves are modified into spine.
Question 3.
Name the hydrostatic organ of rohu fish.
Answer:
Swim bladder.
Question 4.
How many air sacs are present in Pigeon?
Answer:
9 air sacs.
Question 5.
Name one animal where double respiration is seen.
Answer:
Pigeon.
Question 6.
Name the soil where halophytes are developed.
Answer:
Physiologically dry soil.
Question 7.
Name pores present on the breathing root.
Answer:
Pneumatophores.
Question 8.
Name one mammal where RBC is nucleated.
Answer:
Camel.
Question 9.
In camel metabolic water is coming from
Answer:
Fat.
Question 10.
Which tool is used by chimpanzee to break nuts?
Answer:
Hammer.
Question 11.
Waggle dance by bees form which shape?
Answer:
‘8’ shape.
Question 12.
Dance is performed by which caste of bees?
Answer:
Worker.