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LESSON 27 TEKS: 3.10A, 4.10A, 5.10A,B Adaptations The words in bold are vocabulary words that the student should be aware of. To survive, plants and animals must have ways to meet their basic needs. Any feature that helps a living thing survive in its environment is an adaptation. Some adaptations are body parts, such as webbed feet or sharp teeth. Other adaptations are behaviors, or ways an animal acts, such as hibernating or a squirrel storing food for the winter. Each living thing is born with its adaptations. Adaptations do not develop or change during a living thing’s lifetime. But plants and animals that are best suited to the places where they live are most likely to survive and reproduce. Adaptations in Land Environments Tropical rain forests are warm and wet. Plants in a rain forest have plenty of water. But trees and other plants grow so close together that they block the sunlight. Remember that plants need sunlight to make their own food. Many rain forest trees have very long trunks to help them reach the sunlight. Rain forest plants also have wide, flat leaves. These leaves help them to absorb as much sunlight as possible. Many animals in tropical rain forests have adaptations for living in tall trees. Howler monkeys have tails that can grab onto branches. A howler monkey holds on with its tail at all times. Sloths have long, curved claws that let them hang from tree branches. Sloths also use their claws to protect themselves from attackers. Howler monkeys and sloths eat mainly leaves, so they can find food without leaving the trees. The leaves also contain most of the water the animals need. The armadillo has a tough leathery skin that helps protect it from predators. It also has strong claws that it uses for digging to get food and for burrowing to find shelter. The armadillo also has the ability to gulp air to inflate its digestive tract. The inflated digestive tract allows the animal to swim across streams. What is an adaptation? __________________________________________________ 1 In deserts, water is scarce. Desert plants and animals have adaptations that help them survive without much water. Cactuses have roots that spread out near the surface. When rain falls, the roots soak up water quickly before it can dry up in the hot, dry air. Cactuses store the water in their thick stems. Some other desert plants, such as mesquite trees, have very long roots. The roots reach down to water far below the surface. Plants lose water through their leaves, in a process called transpiration. Desert plants can conserve water by having very small leaves. Cactus plants have such small leaves that you can see them only with a microscope. Mesquite trees have small leaves with a way coating. The coating helps keep the leaves from losing water. Cactuses and many other desert plants have sharp spines. Spines help protect the plants from animals that would use them as sources of food and water. Desert animals also have adaptations that help them save water. Many lizards and snakes live in deserts. Lizards and snakes have scales. The scales help keep the animals from losing water through their skin. Many desert animals are active at night, when the air is cool. They sleep during the day in places sheltered from the hot sun. The Arctic tundra in the northern polar region also gets very little rain. The tundra is very cold. Temperatures there can get as cold as -50⁰F. Plants in the tundra can grow for only a short time each year. The plants best suited for this environment are mosses, lichens, and grasses. The polar bear has a number of adaptations that help it survive in this cold ecosystem. It has thick fur that provides warmth and camouflage. It also has a layer of body fat under its skin that can be as much as 4.5 inches thick. The hairs of a polar bear’s thick fur are actually clear, not white. They allow the sunlight to reach the bear’s dark skin to help keep the polar bear warm. What adaptations help a polar bear survive? ______________________________________________________________________________ What 2 adaptations do cactus plants have that help them survive in the desert? ______________________________________________________________________________ How do scales help lizards and snakes that live in the desert? ______________________________________________________________________________ 2 Adaptations in Water Environments There are two main types of water environments – salt water and freshwater. The oceans contain most of the salt water. Rivers and streams contain freshwater– water that is not salty. Lakes, ponds, and many wetlands also contain freshwater. Just as on land, plants and animals have adaptations for different water environments. In the ocean, algae are important producers. Algae are a kind of plankton. Most plankton are tiny organisms that float in the water. Algae and certain other kinds of plankton use sunlight to make their own food. They float near the surface of the ocean where sunlight can reach them. The shapes of large ocean animals are also adaptations for living in water. Both whales and fish have bodies that are narrower in the front and back and wider in the middle. This shape lets them move smoothly and quickly through water. A whale’s smooth skin and a fish’s slippery scales help them glide through the water. A whale uses its flippers to steer and turn, and a fish uses its fins in the same way. However, whales and fish have different adaptations for breathing in water. Whales are mammals that breathe air. They come up to the surface and breathe through the blowholes on top of their heads. Fish take in water through their gills and get the gases they need from the water. Like plant life in salt water, freshwater plants need sunlight to make food. They have adaptations for getting enough sunlight. Water lilies grow in rivers and lakes. Their roots grow down into the soil at the bottom. Their long stems reach up, and their wide leaves float on the water’s surface. Their leaves gather the sunlight that is necessary for photosynthesis. Like saltwater fish, freshwater fish have narrow bodies and fins for swimming. They also have gills for breathing underwater. Frogs and ducks have webbed feet that help them swim in lakes and rivers. How does the shape of the whale and the fish help it to survive in the water? ______________________________________________________________________________ 3 Other Adaptations Camouflage is a pattern or coloring that helps a living thing blend in with its surroundings. A plant or animal that is difficult to see is less likely to be eaten. For example, green tree frogs blend in with the thick green leaves of rain forests. Arctic hares have white fur that blends in with their snowy environment. Camouflage also helps some animals find food. A polar bear’s white fur helps it hide while it hunts. In places where seasons change, animals have adaptations for winter. As the weather gets colder, it is more difficult to find food. Then some animals migrate, or move from one place to another. Geese and monarch butterflies are examples of animals that migrate. Some other animals spend the fall months eating as much food as they can. Then they hibernate, or go into a sleep – like state during winter. When an animal hibernates, its heart beats very slowly. The temperature of its body drops. A hibernating animal uses so little energy that it does not need to eat. It can live off the fat stored in its body until spring. Some animals that hibernate are gophers, bats, frogs, snakes, and ladybugs. How is camouflage helpful to an animal? ____________________________________________________________________________ How can an animals’ coloring help protect it from predators? ____________________________________________________________________________ Why is it helpful for some animals to migrate? ____________________________________________________________________________ How is hibernation helpful to an animal? ____________________________________________________________________________ 4 QUESTIONS 1. Penguins have webbed feet. In which kind of environment would this feature help a penguin survive? A. Ocean B. Desert C. Forest D. Tundra 2. Which animal most likely lives in a cold place? A. A fox with thick fur B. A frog that is green C. A rat with little fat D. A coyote that sleeps during the day 3. Which adaptation helps some plants that live in dry deserts? A. Tall trunks B. Long roots C. Thin stems D. Floating leaves 4. An animal that sleeps during the day most likely lives in A. A tropical rain forest B. A tundra region C. A tide pool D. A hot desert 5. Which of these is not an adaptation for a polar bear? A. Dark skin B. Front paws for swimming C. Thick layer of body fat D. Gills for living and breathing under water 6. Which adaptation would best help an owl catch a mouse? A. Camouflage B. Hollow bones C. Talons or claws D. Pointed ears 5