Life Science Unit Test Review Name

Basic Needs of Animals

Humans, like other animals, have basic needs for survival. An animal's habitat is the place where it can find the things it needs to live.

The basic needs of animals include shelter, food, water, air, space, waste removal, and a particular range of temperatures.

Shelter—Animals need shelter because it protects them from the elements and from predators. A bird's nest is an example of shelter.

Food—Animals need food because it provides energy and nutrients necessary to the body to perform life functions. Some animals eat plants. Some animals eat other animals.

Water—Animals need water because it transports nutrients and wastes in the body, and it helps keep body temperatures constant.

Air—Animals need air because oxygen is needed for the chemical process that releases energy from food.

Space—Animals need space because overcrowded areas lead to starvation and disease.

Waste removal—Animals need waste removal because waste is produced as animals use food, water, and air for life processes. Animals must be able to get rid of this waste to survive.

Temperature range—Animals are best suited to survive in certain temperature ranges.

Animals meet their needs in the habitat, or environment, in which they live. The environment is everything that surrounds and affects an animal. This includes the plants and other animals in the area, rocks, soil, air, and water. Both living and non-living things are part of an environment.

Basic Needs of PlantsPlants need five things to live and grow: sunlight, water, air, minerals, and space. When one of these basic needs is not met, the plant is unable to live and grow.

Sunlight—Plants get energy from the Sun. Chlorophyll found in plant leaves uses sunlight to change water, minerals, and carbon dioxide into food. This process is called photosynthesis.

Water—Plants must have water because it helps carry nutrients from the soil to the plant's roots. Water is a part of plant cells and is a main ingredient for photosynthesis.

Minerals—Plants need soil because they use it to get water, nutrients, and minerals.

Air—Plants also get nutrients from the air. During photosynthesis, plants take in carbon dioxide from the air and release oxygen.

Space—Plants also need space to grow. If there are too many plants for the amount of sunlight, soil, minerals, or space, some of the plants will not survive.

Environmental AdaptationsThe Earth is made up of many different environments. Some examples are deserts, rainforests, oceans, mountains, forests, and ponds. Organisms have special adaptations that help them survive in their environments.

Adaptations Must Match the EnvironmentAn environment is the area where an organism lives and all the physical factors that affect the survival of that organism. These factors include, among other things, climate, predators, food, and shelter.Each environment is made up of its own special set of living conditions. Organisms have physical and behavioraladaptations to help them live in their environment. How well a living thing can survive depends on how well its adaptations match its environment. Which type of environment an organism will most likely live in can be found by comparing the animal's adaptations with the conditions of different environments.

Different Kinds of EnvironmentsThe Arctic is a very cold part of the Earth. The organisms that live here must all have adaptations that allow them to survive in temperatures far below freezing. Polar bears have thick fur and padded feet that help them to stay warm. The Arctic fox has thick fur that turns white during the winter. Its fur is camouflage that helps keep predators or prey from seeing the fox. The chipmunk burrows underground and hibernates all through the cold season.

The arctic fox and the polar bear are well-adapted for life in the cold. The pack rat and the cactus can survive on very little water.

The desert is a very dry environment, so plants and animals there have adapted to need less water. The cactus has a large stem that stores water from infrequent rainfall. It also uses its large spikes to shade itself from the intense sun.Many desert animals do not need to drink water at all because they get it from the food they eat. Deserts are usually hot during the day and cold at night, so animals have adapted to control their body temperature.

The slow-moving sloth is adapted to the rainforest: green algae grows on its fur and camouflages it from predators.Giraffes survive in the savanna because their long necks allow them to reach parts of plants that no other animal can.Their necks also help them to see and escape from predators. Pelicans do well near water because their pouched beaks act as fishing nets.

Structural Adaptations in AnimalsAn adaptation is a special structure or behavior that helps an organism survive in its environment.All animals have adapted to have special structures that help them survive. These adaptations are ways that the animal can find food, find shelter, survive certain weather conditions, or protect themselves.

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Catching & Taking in FoodWithout food, animals cannot survive. All animals have adapted to have structures that allow them to get food and take that food into their bodies. For example, sharks have a strong sense of smell that allows them to locate food, and they have teeth that allow them to attack their prey. Pelicans have enormous, pouched bills that they can expand to scoop fish up out of the ocean or other body of water.

Sharks and pelicans have different kinds of mouths that allow them to catch and eat different kinds of food.

Lizards have long, fast-moving tongues that allow them to catch insects. Cats have sharp teeth that can be used for tearing meat. Rabbits have dull, flat back teeth that help them chew up grass and other plants.Giraffes have long necks that allow them to reach high into trees and get food. Hawks have sharp, curved beaks that allow them to catch and eat prey more easily. Hawks have excellent eyesight that helps them see small prey animals from very far away.

MovingMost animals can move from place to place. This allows them to look for food and water and to avoid being eaten by other animals. All animals

have special structural adaptations that help them move. For example, ducks have webbed feet that allow them to be able to swim in the water and catch insects and small fish there. Rabbits, frogs, and kangaroos have powerful hind legs, which they use for jumping. Cats have strong legs for running quickly after prey. Fish have fins that help them easily swim through the water. Birds have wings and feathers that help them fly.

Animals have structures that help them move in their environments.

Finding ShelterAdaptations also help animals to find shelter. For example, woodpeckers have sharp beaks that allow them to tunnel through trees and make hollows. They make their nests in these hollows. Squirrels and many other kinds of animals that cannot fly also live in trees. These animals often have claws that allow them to climb the trees easily.

Many animals, such as prairie dogs, foxes, and rabbits, live in burrows. These animals have feet with claws that can be used for digging.

The woodpecker and the squirrel both have structures that allow them to use trees for shelter.

Surviving the WeatherAdaptations also help plants and animals to survive weather conditions in their environment. For example, polar bears and wolves have thick fur and padded paws to help them survive the extreme weather of the Arctic. Emperor penguins, seals, and walruses have thick layers of blubber that help to keep them warm in cold areas.

Polar bears and emperor penguins have adaptations that help them survive in cold climates.

Protection from PredatorsAdaptations also help plants and animals to protect themselves. One method of protection is camouflage, which is when the animal's appearance helps it to blend into its environment. Some birds, insects, lizards, frogs, and other animals have special skin or outer covering that camouflages them and makes them hard for predators to see.

Some animals protect themselves by mimicking, or looking similar, to other animals. This is called mimicry. One example of mimicry is a type of wasp that does not sting but looks similar The lizard and the stick insect have outer coverings that to a stinging wasp. Still other animals protect themselves with very sharp senses which camouflage them and protect them against predators. result from the structure of their sense organs, such as noses. For example, rabbits have huge ears that they can use to hear predators with. Deer have an excellent sense of smell.

Behavioral Adaptations in AnimalsAnimals have adapted to have behaviors that help them survive in their environments.There are many different environments on Earth, and many different types of animals live in most of these environments. Each animal has special behaviors that help it survive the climate conditions of the environment. Other behaviors help the animal escape from predators or find and catch food.Some important types of behavioral adaptations are discussed more in the sections below.

Defense Against the Environment Keeping cool in warm climates—Animals that live in very warm climates, such as deserts, have

behaviors that help keep them from getting dangerously hot. Many desert animals are active only at night, when the temperatures have dropped. For example, this gecko, which lives in desert areas of the southwestern United States, stays in its burrow during very hot parts of the day. It comes out in search of food during the night, when it is much cooler.

Surviving seasonal temperature changes—Many animals live in areas where the weather changes from season to season. All of the wild animals in areas with very cold winters have behaviors that help them to survive the cold. For example, flying birds such as the tundra swan move to warmer parts of the world to avoid the colder weather of winter. This is called migrating.Animals also adapt to changes in the food available as a result of seasonal changes. For example, some types of squirrels store nuts for winter, while bats, hedgehogs, some squirrels, and some other animals hibernate in winter to survive the long period when there is little food available.

Surviving habitat change—When an animal's habitat changes, the animal must move away to a new habitat or find a way to live in the changed habitat. If it cannot do either of these things, it may die. One example of animals behaving differently in a changed habitat is birds building nests in structures built by humans.

Defense Against PredatorsMany animals are predators. That means that they hunt and eat other kinds of animals for food. But many predators are also prey, because they are eaten by other kinds of animals. All prey animals have behaviors that help protect them from predators.

For example, when opossums, like the ones shown below, feel threatened by a predator, they roll over onto their backs and appear to be dead. Predators usually attack only live animals, so they leave the "dead" opossums alone.

Another example of how animals have behaviors that protect them from predators is that a turtle pulls its head and feet up into its shell when it senses a predator. Horned lizards have still another protective behavior. They squirt a stream of blood out of their eyes at a predator. The blood tastes bad to some predators, and it also confuses them. Finally, snakes protect themselves by hissing, baring their fangs, and striking, or trying to bite a predator.

Stalking PreyJust as prey animals have behaviors that help defend them against predators, predators have behaviors that help them hunt prey more successfully. For example, many kinds of wild cats stalk their prey. This means that they hide in trees, tall grass, or close to the ground and stay very still or move only very slowly. They watch for a prey animal to come near, and then they move very quickly from their hiding spot and attack the prey animal.

Matter & Energy in Ecosystems

The energy in most ecosystems is provided by the Sun.Producers absorb energy directly from the Sun to make food. This energy is transferred to consumers when they eat producers. Decomposers get their energy by feeding on dead plant and animal material.

ProducersProducers are organisms that use the Sun's energy to make their own food. Green plants are producers. They make their own food using energy from the Sun in a process called photosynthesis. Other producers include algae and some kinds of bacteria and protists. All of the other organisms in an ecosystem depend on producers for energy. This is because animals, including humans, cannot make their own food.

Green plants, such as grass and trees, are producers that use energy from the Sun to make food.

ConsumersConsumers are animals that get energy by eating producers (plants) or other consumers. There are three main kinds of consumers: primary consumers, secondary consumers, and tertiary consumers. The classification given to a consumer depends on where it is positioned in a food chain.

Primary consumers are animals that eat producers. Primary consumers are also called herbivores because they eat only plants. A deer that eats only leaves and grass is a primary consumer and an herbivore.

Secondary consumers are organisms that eat primary consumers. Secondary consumers can be carnivores if they eat only animals. Or, they can be omnivores if they eat both animals and plants. A wolf that kills and eats a deer is a secondary consumer and a carnivore.

Tertiary consumers eat secondary consumers, and they are also carnivores or omnivores. A bear that eats a fish that has fed on other fish is a tertiary consumer. Since the bear also eats berries and other plants, it is an omnivore.

DecomposersDecomposers are organisms that get energy from feeding on wastes and dead plants and animals. Fungi, such as mushrooms, are examples of decomposers. Some kinds of bacteria and insects are also decomposers. The role that decomposers play in an ecosystem is very important. Decomposers "clean" the environment by returning matter and nutrients that were contained in the bodies of dead plants and animals back to the soil. The nutrients that decomposers release into the soil are used by producers for growth.

Food Chains & Webs

Fungi and some insects, such as this dung beetle, are decomposers.

The energy flow through an ecosystem can be shown in two main ways: food chains and food webs.

Food ChainsA food chain describes the feeding relationships and energy flow between species within an ecosystem.The ultimate source of energy for most ecosystems is the Sun. Producers receive energy from the Sun and make food.Producers are the beginning of a food chain because all of the other organisms in the food chain depend on the food energy that is made by producers. The next organisms in the food chain are primary consumers, which eat producers.Next come secondary consumers, then tertiary consumers, and so forth until the top

carnivore is reached.

The food chain above shows the flow of energy from a producer, algae, to the consumers in the ecosystem. Minnows are primary consumers, salmon are secondary consumers, and bears are tertiary consumers.

The arrows in a food chain represent the direction of energy flow. For example, in the food chain above, an arrow points from the algae to the minnow. This means that the minnow is eating the algae and receiving energy from it.

Watch the video below to see the feeding relationships between different organisms.

Since all organisms in the food chain are eventually broken down by them, decomposers are often left out of food chains. Examples of decomposers include fungi, bacteria, and worms.

Food WebsA food web is a group of interconnected food chains. Organisms in a food web can belong to multiple feeding levels within a food web.

For example, in the food web below, krill are both primary and secondary consumers. Krill are primary consumers because they eat phytoplankton, which are producers. Krill are also secondary consumers because they eat zooplankton, which are primary consumers.

An Antarctic food web is shown in the picture above. Organisms in food webs can belong to more than one feeding level.

Effect of Environmental Change on Food Chains

Organisms in an ecosystem affect each other. A change in the number of one kind of organism will cause a change in the number of other kinds of organisms.

Energy Flow in Food ChainsEnergy in a food chain flows from plants to animals that eat the plants and then to animals that eat those animals. For example, in the food chain below, energy flows from the tree to the termite and then to the kinkajou and the jaguar.

Environmental Change can Cause Food Chains to Become UnbalancedEnvironmental change may change the number of a certain kind of organisms in an ecosystem. This, in turn, will affect the numbers of other kinds of organisms.If the amount of plants in an ecosystem increases, more food is available for the animals that eat those plants. An increase in an organism's food supply can lead to an increased number of that organism. But if the number of plants becomes smaller, the numbers of animals in the ecosystem will also shrink. This is because the animals will have to compete more for food.Predators are animals that eat other animals, called prey, for food. If there aren't enough prey (like termites) for the predators (like kinkajous) to eat, there will not be as many predators.Predators also keep populations of other animals at the right size. But if there are not enough predators (jaguars), there will be too many prey (kinkajous). If there are too many kinkajous, there will not be enough termites to feed them all.