B2e - adaptations

Question 1

Explain how adaptations to cold environments help
organisms survive(2+1+3)

Answer 1

Anatomical adaptations:

• thick fur/layer of blubber which insulates body by trapping heat in; also acts as camouflage
• large size/compact body shape, so small surface area to volume ration, so less ­heat loss through surface of skin

Physiological adaptations:
-counter ­current heat exchange system - blood vessels near the feet are close to each other, allowing warm blood entering the feet to warm up the cold blood leaving, stops cold blood from cooling down rest of body and minimises heat loss

Behavioural adaptations:

• migration to warmer climates during winter
• hibernation during winter, slowing down life processes until conditions improve to save energy
• huddling together to keep warm

Question 2

Explain how adaptations to hot environments help
organisms survive(4+3)

Answer 2

Anatomical adaptations:

• small body size/large ears,so larger surface area to volume ration, so more heat loss through surface of skin
• large thin ears, which allows more blood to flow near surface of skin, so more heat from blood lost to surrounding through radiation
• humps of fat(camels), so fat is stored in one place, less all round insulation, which allows heat to be lost more easily
• thin fur, so less warm air is trapped and reduced insulation

Behavioural adaptations:

• spend day in shade or underground, minimise amount of heat gained by body from surroundings
• active at night, when it is much cooler, so less ­heat gain
• bathing in water to to increase heat loss, since as water evaporates, it transfers heat from skin to surroundings, cooling animal down

Question 3

Explain how adaptations to dry environments help animals survive(3+1)

Answer 3

Anatomical adaptations:

• specialised kidneys which allows production of concentrated urine with low water content, ­so less water loss via excretion
• no sweat glands, preventing water loss through sweating
• hump of fat which can be broken down to release water

Behavioural adaptations:
-spend time in underground burrows where air contains more moisture than on surface

Question 4

Explain how adaptations to dry environments help plants survive(6)

Answer 4

Anatomical adaptations:

• spines instead of leaves to reduce surface area to volume ratio, and reduce water loss; also less likely to be eaten
• thick wax cuticle to reduce and reduce water loss
• shallow root system to cover great areas and to absorb more water when it rains
• store water in stems to survive in times of extreme drought
• rounded shape to reduce surface area to volume ratio, and reduce water loss
• green stem for photosynthesis

Question 5

Describe some biochemical adaptations to extreme temperatures(2)

Answer 5

Some organisms living in cold climates have antifreeze proteins in their cells

Extremophiles(organisms that can survive in hot conditions)(e.g. bacteria) have enzymes that have higher optimum temperatures where normal enzymes would denature

Question 6

What are some benefits for animals and plants of being adapted to habitat(2)

Answer 6

Makes them better suited to their environment and better able to compete for limited resources;

More likely to survive, reproduce and pass on their adaptations to their offspring

Question 7

Describe specialists(3)

Answer 7

Organisms which are highly­adapted to survive in a specific habitat

Outcompeted by generalists in habitats where conditions changes constantly
-they won’t be adapted to the new conditions, but generalists are adapted to a range of conditions so are more likely to survive

Question 8

Describe generalists(3)

Answer 8

Organisms that are adapted to survive in a range of different habitats but can easily be out­competed

Outcompeted in habitats where the conditions are stable
-specialists are better adapted to the specific conditions