Variation and Selection: Chapter 18, Bio WRP 29.7.22 Part 2.1: Adaptive features
An adaptive feature is an inherited feature that helps an organism to survive and reproduce in its environment.
A water beetle:
When compared to a land beetle, it has long, hair fringed legs which helps it in locomotion in water.
The camel:
Adapted to survive in hot, dry environment.
Closable nostrils, and long eyelashes help keep out wind- blown sand.
Their feet are broad (prevents them from sinking into the sand).
Thick fur insulates body from heat gain.
Stomach has large water holding capacity, and the ability to variate the temperature of the stomach.
Able to tolerate water loss upto 20% of of its weight.
Mucus in nasal passages absorbs water vapour during exhalation (conserves water).
Hump is an energy reserve (so the fat is metabolised during respiration).
Polar bears:
Adapted to living in a cold environment.
Ratio of its surface area to volume is relatively small. (Reduced heat loss by radiation).
Long, loosely- packed coarse hairs (Oily and water repellent).
Shorter, densely packed woolly hairs (Insulating layer).
Blubber (allows very little heat to circulate close to the skin)
White coat (provides effective camouflage, transmits sun's heat to the black skin below).
Black skin (Absorbs heat).
The heat- exchange arrangement in feet.