Key Points
This section will give you the main information you should know to teach the activity.

• Adaptations are body parts or behaviors that help a plant or animal to survive in its environment
• An organism's adaptations determine the organism's role in the community; whether it is a carnivore, herbivore or producer; whether it walks, swims or flies; what it can eat and what can eat it and other interactions in the community.
• An animal or plant's adaptations are often designed for a specific environment, and because of this, the animal or plant could not survive outside this environment

Each type of plant or animal has different structural adaptations that serve different functions. Blue crabs have claws that aid in defense and in the acquisition of food. Octopus have pigment-filled cells that can contract and expand, allowing the animal to be a master of camouflage. Male seahorses have pockets on their bodies in which to brood young. Plants have stems that transport water up from the roots. Such structural adaptations aid in survival and allow plants and animals, like those mentioned above, to respond to life needs. Likewise, plants and animals have behavioral adaptations that help them to survive in their environment. Plants bend towards sunlight to efficiently capture the energy from the sun. Hermit crabs quickly retreat to the confines of their shell if a shadow passes overhead.

The adaptations of individual plants and animals are suited to the environments in which they live. Fish have fins that propel them through water. Birds have feathered wings that enable flight in air. Clues to the environments in which plants and animals live are often provided through close observation of an organism's body parts and body design. Take, for example, the beachside plant, the sea rocket. This plant has succulent, thick, fleshy leaves that help the plant to conserve water. The leaves of the plant are silvery to reflect harsh sunlight and have a waxy covering that protects the plant from salt spray. On the other hand, the leaves of deciduous trees located in less harsh environments (than the dune environment of the sea rocket) are thin and broad and lack the succulent, waxy nature of those of the coastal sea rocket; deciduous trees are not found in the harsh, dune environment and, therefore, do not need added protection from excessive sunlight or salt spray. Consider the delicate body of a jellyfish. Would you expect to find this animal in rushing currents, amongst a rocky reef or moving around on land? The delicate, watery body of the jelly is designed for life in the open ocean, where buoyancy is crucial and boundaries do not exist. Jellies, as members of the plankton community, are at the mercy of the currents. Those that are pushed close to inshore beaches, often meet their death where waves and sandy beaches meet; they are not adapted to survive in the immediate nearshore environment.

Animals that live both in water and on land have adaptations that help them to survive in both environments. The life cycle of amphibians clearly demonstrates the link between adaptations and their function(s). Baby frogs, or tadpoles, are strictly aquatic and quick observation easily reveals adaptations for life in an aquatic world: lack of limbs and a "fish-like" tail fin. However, as tadpoles morph into their adult form, their adaptations become suited to terrestrial life: lack of a "fish-like" tail fin and four limbs. Some animals, like the green sea turtle, have lives tied to land only for reproduction and the adaptations of the animal reflect a primarily aquatic life. Female green sea turtles lumber their huge bodies across a stretch of sandy beach to lay their eggs. The huge size makes movement on land quite laborious. However, in water the huge size is an advantage to not becoming a meal. The presence of four limbs enables movement on land. However, the flipper-like appendages are far more efficient in a watery world.

Individuals in a population of any species vary in many traits that are inherited from their parents. Since members of a species have the potential to produce far more offspring, or young, than the environment can possibly support with space, food, water and other resources, a constant struggle for existence among the varied members of a population is inevitable. Charles Darwin calculated that in just 750 years a single pair of elephants would have 19 million living descendants, provided that every descendent along the way lived to be 100 years old and had just six surviving offspring. But elephants and most other populations remain stable because most of the young animals generated by a species die without reproducing. The "winners" of this constant struggle for existence are those individuals with adaptations best suited to the local environment. Adaptations are body part or behaviors that help an organism to survive in its environment. Because of their special, inherited traits, some individuals are likely to be better able to avoid predators, to find food or mates or to deal with climatic pressures. These individuals will tend to survive longer and leave more offspring than others in their species that have different and less successful adaptations.