A DAPTATIONS Biology ATAR Unit 2

Adaptation The inherited characteristic that makes an organism well suited to its environment and lifestyle. Adaptations enhance an organism's ability to survive and reproduce in a particular environment. Different types of habitats include: Terrestrial Aquatic  Freshwater  Marine A DAPTATIONS

T ERRESTRIAL HABITATS Terrestrial plants and animals need water, oxygen and some form of protection or shelter from environmental conditions such as wind and temperature. Terrestrial organisms are often exposed to extreme temperature changes due to weather conditions and the seasons, with water loss a constant problem for many terrestrial organisms.

A QUATIC HABITATS There are four abiotic factors that affect plant and animal life in water: 1. Oxygen is not very soluble in water. 2. Light rarely reaches 100 metres below the surface. 3. The temperature of water decreases with depth. 4. The water often has either a higher salt concentration or a lower salt concentration than the organisms’ cells.

T YPES OF ADAPTATIONS Adaptations can be classified into three categories: 1. Structural  Colour  Mimicry 2. Behavioural 3. Physiological.

S TRUCTURAL ADAPTATIONS Structural adaptations are the physical features of an organism that help it to survive in its environment Examples An insect’s mouth parts allow it to obtain food from different parts of a plant. The leaves of the mulga tree are narrow in order to reduce water loss through evaporation The leafy sea dragon is protected because it looks like seaweed.

S TRUCTURAL ADAPTATIONS S TRUCTURAL ADAPTATIONS P ROTECTIVE C OLOURATION Colouration and protective resemblance allow an animal to blend into its environment. Their camouflage makes it hard for enemies to single out individuals.

S TRUCTURAL ADAPTATIONS S TRUCTURAL ADAPTATIONS M IMICRY Mimicry allows one animal to look, sound, or act like another animal to fool predators into thinking it is poisonous or dangerous.

B EHAVIOURAL ADAPTATIONS Behavioural adaptation is the way an organism behaves or acts to survive in its environment Examples Kangaroos rest in shade during the heat of the day. Kangaroos pant or lick their forearms to lose body heat by evaporation.

B EHAVIOURAL ADAPTATIONS The desert hopping mouse is nocturnal and stays in its burrow during the day to avoid extremes of temperature. Birds will migrate to places where water and food are more plentiful.

P HYSIOLOGICAL ADAPTATIONS Physiological adaptations relate to the functioning of the body and how it reacts internally to enhance survival in response to environmental change. Example Red kangaroos living in an environment where drinking water is scarce produce very concentrated urine, which conserves water and enables them to tolerate salty drinking water.

P HYSIOLOGICAL ADAPTATIONS Examples Mangroves have physiological adaptations to survive in salty estuaries. Excess salt is stored in the leaves and removed when the leaves fall off. A koala's low metabolic rate and low energy requirements enable it to obtain sufficient nutrients and water from a diet of only gum leaves.

T HE B ILBY : AN A USTRALIAN EXAMPLE The bilby once lived across most of the Australian inland deserts. Today its range is a lot more restricted (primarily due to the environmental problems that humans cause). Only small, fragmented populations survive in parts of the Tanami, the Gibson and the Great Sandy deserts. Like most desert animals the bilby hides during the day and forages at night to avoid heat and dehydration. Bilbies dig burrows that are one to two metres below ground and moister and up to ten degrees cooler than the surface. They are so efficient in conserving water that they don't need to drink. They get enough moisture from their food: seeds, bulbs, fungi, spiders and insects, which they find by scratching and digging.