Adaptations For Survival – Methods Adaptations For Survival – Methods Of Avoiding Extremes Of Climate. Dormancy 1. Plants Annuals -survive cold / drought as seeds. Perennials – organs of perennation – bulbs, tubers, rhizomes. Deciduous trees loose leaves, reducing transpiration rate. 2.
Animals Small mammals and ectotherm's hibernate. Need to increase body fat. Reduced metabolic rate. Migration eg. Many birds migrate to find improved food sources and warmer temperatures. Depression of freezing point in cells Plants and animals in cold climates survive by having substances within cells that depress freezing point eg increasing solutes in cells anti freeze substances eg glycerol.
Also having air spaces within gut or inside leaves insulates and so prevents damaging effects of ice crystals formed when water freezes. Xerophytes Plants adapted to withstand dry conditions eg marr am grass, cacti. Roll leaves to reduce evaporation from stoma Stoma in sunken pits Hairs on underside leaves. Surface area of leaves reduced – needles Increased thickness of cuticle.
Body size and shape Animals with large surface areas to volume ration (smaller animals) loose heat more quickly than with smaller surface area to volume ratio. Loose heat by conduction, convection and radiation. Animals in cold climates tend to be larger with smaller extremities than those in warm climates. Counter current exchange of heat through limbs prevents excessive heat loss.