Anatomical adaptations are structural features of an organism's body, inside or outside. They include body shape, size, colour and the structure of organs and tissues.Animals in cold climates
The Arctic fox has small ears and a compact rounded body. These reduce its surface area to volume ratio, so less heat is lost. Thick fur and a layer of fat (blubber in seals and whales) insulate the body. White winter fur provides camouflage against snow.Animals in hot climates
The fennec fox of the Sahara has very large ears with many blood vessels, which increase heat loss. Desert kangaroo rats have very long loops of Henle in their kidneys, so they can produce very concentrated urine and lose little water.Aquatic animals
Dolphins and fish have streamlined bodies that reduce drag, so less energy is used in swimming.Plants in dry habitats (xerophytes)
• Cacti have leaves reduced to spines, which reduces the surface area for water loss and deters animals. Their thick, swollen stems store water.
• Marram grass, which grows on sand dunes, has rolled leaves, sunken stomata and hairs. These trap moist air near the stomata, reducing the water potential gradient and so reducing transpiration.
• Many xerophytes have a thick waxy cuticle and deep or widespread roots.Each of these features is inherited and has become common in the population through natural selection.
The Arctic fox has small ears and a compact rounded body. These reduce its surface area to volume ratio, so less heat is lost. Thick fur and a layer of fat (blubber in seals and whales) insulate the body. White winter fur provides camouflage against snow.Animals in hot climates
The fennec fox of the Sahara has very large ears with many blood vessels, which increase heat loss. Desert kangaroo rats have very long loops of Henle in their kidneys, so they can produce very concentrated urine and lose little water.Aquatic animals
Dolphins and fish have streamlined bodies that reduce drag, so less energy is used in swimming.Plants in dry habitats (xerophytes)
• Cacti have leaves reduced to spines, which reduces the surface area for water loss and deters animals. Their thick, swollen stems store water.
• Marram grass, which grows on sand dunes, has rolled leaves, sunken stomata and hairs. These trap moist air near the stomata, reducing the water potential gradient and so reducing transpiration.
• Many xerophytes have a thick waxy cuticle and deep or widespread roots.Each of these features is inherited and has become common in the population through natural selection.