AQA Core Biology 1b (i) - Evolution and Environment
Adapt and Survive.
Animals and plants survive in many different environments, from hot deserts to cold polar regions, and pretty much everywhere in between. They can do this because they have adapted to their environment.
Desert Animals Have Adapted to Save Water.
Animals that live in hot, dry conditions need to keep cool and use water efficiently.
LARGE SURFACE AREA COMPARED TO VOLUME.
This lets desert animals lose more body heat, which helps them stop overheating.
EFFICIENT WITH WATER.
1) Desert animals lose less water by prodcucing small amounts of concentrated urine.
2) They also make very little sweat. Camels are able to do this by tolerating big changes in body temperature, while kangaroo rats live in burrows underground where it is cool.
GOO IN HOT SANDY CONDITIONS.
1) Desert animals have very thin layers of body fat to help them lose body heat Camels keep nearly all there fat in their humps.
2) Large feet spread their weight across soft sand, making getting about easier.
3) A sandy colour gives them good camouflage, so they are not as easy for their predators to spot.
Arctic Animals Have Adapted to Reduce Heat Loss.
Animals that live in really cold conditions need to keep warm.
SMALL SURFACE AREA COMPARED TO VOLUME.
Animals living in cold conditions have a compact (rounded) shape to keep their surface area to a minimum, this reduces heat loss.
1) They have a thick layer of blubber for insulation, this also acts as an energy store when food is scarce.
2) Thick hairy coats keep in body heat in, and greasy fur sheds water (this prevents cooling by evaporation).
GOOD IN SNOWY CONDITIONS.
1) Arctic animals have white fur to match their surroundings, for camouflage.
2) Big feet help by spreading weight, which stops animals sinking into the snow or breaking the ice.
Some Plants Have Adapted to Living in a Desert.
Desert-dwelling plants make the best use of what little water is available.
MINIMISING WATER LOSS.
1) Cacti have spines instead of leaves, to reduce water loss.
2) They also have a small surface area compared to their size (about 1000 times smaller than other plants), which also reduces water loss.
3) A cactus stores water in its thick steam.
MAXIMIZING WATER ABSORPTION.
Some cacti have shallow but extensive roots to absorb water quickly over a large surface area. Others have deep roots to access underground water.
Some Plants and Animals Have Adapted to Deter Predators.
There are various special features used bu animals and plants to help protect them against being eaten.
1) Some plants and animals have armor, like roses (with thorns), cacti (with sharp spines) and tortoises (with hard shells).
2) Others produce poisons like bees and poison ivy.
3) And some have warning colours like wasps to scare off predators.
Populations and Competition.
Often different organisms have adapted to suit the same environment and use the same resources, which means sooner or later they will have to fight for survival.
The Size of Any Population…