Key Concept 1: Plants and animals have specific structures and functions that enable them to be successful in their environments. Adaptations help a plant or animal survive. The English naturalist Charles Darwin realized over 150 years ago that physical features (structures) and how they are used (functions) took many generations to develop. He observed that those species of animals and plants that were able to survive and reproduce were those which had best adapted to the challenges of their environments. He called this natural ability to adapt natural selection. Plant Adaptations - In the rain forest with its heavy green foliage, the competition is not for water, but for sunlight. As a result, plants in rain forests adapt by growing taller and faster than neighboring plants to reach the sunlight. Those plants that are in deep shade areas will have darker green and red leaves to absorb as much light as possible. In Arctic regions, although there is plenty of sunlight during the summer, the wind blows unmercifully in the unprotected landscape. As a result, trees grow very low to the ground, sometimes no more than a few inches tall, to avoid the howling wind. The plants are also smaller than similar species at lower latitudes because of a shorter growing season farther north. Many factors determine which adaptations will ensure survival. Plants release moisture through their leaves. However, in the desert where water is scarce, plants like cacti have leaves that resemble sharp spines so that a minimum amount of leaf surface area is exposed to transpiration. The spines also act as protection, since the cacti are so rich in water under the waxy coating. Cacti can store gallons of water in their trunks to be used sparingly during periods of no rain. Desert plants have roots that spread wide and extend deep into the ground to capture every valuable drop of water. Even a houseplant, when placed near sunlight, will grow toward the light source in an adaptation to its environment. Every part of a plant, root, stem or trunk, leaf, flower or fruit, is vital to the survival of the plant, and as such has been adapted to respond to the effects of the environment around it. Feet Adaptations - Animals, too, are products, or reflections, of their environments. Many animals that live in an aquatic environment have webbed feet to aid swimming both in cold and warm water. Beyond that, many waterfowl, such as ducks and geese, and even polar bear and otter feet are webbed. The flaps of skin between the toes of webbed feet allow the animal to push against the water with greater force for faster swimming to catch food or to escape from predators. Sharp claws are an adaptation of many animals that need running speed, climbing ability, digging prowess, or hunting skills. Hooves on horses and antelopes allow them to run faster and more easily over hard prairie ground. A hoof is simply one large, modified toenail that supports the entire foot and leg. The sucker-like feet on a Gecko lizard allow it to cling to objects to hide from predators or to wait for food. The grasping feet of tree monkeys allow them to swing from limb to limb. Limb Adaptations - Flippers on penguins and seals are adaptations that allow these animals to swim rapidly, either to find food or to escape a predator. The strong back legs of rabbits, kangaroos, and cheetahs allow the animals to leap and run long distances, either to escape predators or to catch prey. Mouth Adaptations - An animal’s teeth will often indicate its source of food. Sharp teeth reveal a carnivore (meat eater), while broad, flat teeth for grinding food belong to an herbivore (plant eater). The beaks of birds vary according to diet. The crane has a long, narrow beak to reach deep into water for small fish, while a finch has a short, powerful beak for cracking nuts and seeds. Predators, such as eagles and hawks, have curved, sharp beaks for tearing chunks of flesh from their prey. Defense Adaptations - By having a color or shape that blends with the environment (camouflage), the organism is better able to hide from its enemies and stalk its prey. A lizard can change skin color to blend in with its environment. A baby deer has spots to hide it from predators. An arctic hare is white in the winter to blend in with the snow-covered terrain. Sometimes, an animal resembles another organism or its surroundings to better survive (mimicry). Some insects look like leaves, while other insects resemble a stick to hide themselves. The Dragon Seahorse resembles a leafy aquatic plant in order to hide from predators. Some animals try to appear larger to scare off predators, such as a cat arching its back. Temperature Adaptations - In the frigid regions of the North or South Poles, animals like polar bears or seals have thick layers of blubber underneath thick skins to protect them from the ice and freezing water. In hot desert environments, animals have adapted to a small size, such as the kangaroo mouse, or thick skins, such as scorpions, to prevent water loss. Migration (seasonal movement of an organism from one place to another) is an adaptation to extreme temperatures and reduced food supplies during winter. Many birds migrate to southern areas to wait out frigid temperatures. The Monarch butterfly travels to central Mexico, over thousands of miles, during winter. The Arctic tern, gray whale, and African elephant are other examples of animals that migrate long distances due to seasonal changes. Hibernation (when an animal becomes still in an enclosed space, and reduces body functions to save energy) is another adaptation to seasonal changes. For example, bears, bats, squirrels, and frogs slow down their metabolism (body functions) to hibernate during winter.