19. How do you know these animals areHow do you know these animals are
alive?alive?
How do they satisfy their basicHow do they satisfy their basic
needs?needs?
- finding food- finding food
- eating- eating
- having offspring- having offspring
- water- water
- shelter- shelter
- avoiding being eaten- avoiding being eaten
Editor's Notes
Aphids are small insects that feed on the juices of plants. When a plant has many aphids it may not be healthy and could die. Some aphids are cared for by ants who “drink” the sugary liquid produced by the aphids.
Fleas are parasites. They feed on the blood of animals like dogs, cats, and humans. They are some of the greatest jumpers for their size on Earth. Using their powerful hind legs, they can jump upwards 7 inches and lengthwise 13 inches. Their bodies are very flat side to side making it very easy for them to move between the hairs of your pet.
Lice are also parasites. They live in the hair, fur, or feathers of animals. They feed on skin, oils, and blood of the animal. They attach their eggs to the hair of the animal and it is very difficult to remove them. Special medicines are needed to get rid of the lice.
Nematodes are among the most common animals on Earth. There are over 80,000 different kinds of nematodes. They are found everywhere, in the soil, in salt water, in freshwater and even in Antarctica and in the deepest parts of the ocean. Most of them are microscopic, but a few forms can grow to over one meter in length. Notice how the nematode moves.
Brine shrimp are found in salt water. They are sometimes called “sea monkeys.” They have many swimming legs that help them move quickly in the water. Often, brine shrimp are used as food for fish in salt-water aquariums.
Copepods are one of the most common animals found in the ocean. However, they are found in many other areas as well – ponds, puddles, sea floor, swamps, and even in caves. They are a very good food source for many other animals. They eat smaller microscopic organisms. As you can see, they have a body shape something like their cousin the shrimp.
Midges are very small two-winged insects. They are sometimes called “no-see-ums” because they are so small that we often don’t see them. They are also called sand flies. This is a biting midge that can suck the blood of humans. Some biting midges and can spread disease in cattle. There is a great variety of kinds of midges. Some types of midges live on plants and can cause an abnormal growth called a gall.
This is the larvae of a midge and it lives in the water.
Like other insects, mosquitoes have six legs. During the day, mosquitoes stay in cool places. In the evening, they are more active. This is when you might get bitten by a female mosquito. Male mosquitoes do not bite.
These are mosquito larvae (young mosquitoes). The female mosquito does not need your blood for food, but needs some of the nutrients for development of eggs. The female mosquito lays her eggs in water where the young mosquitoes (larvae) develop. Eventually the larvae develop into adult mosquitoes.
Daphnia is also called water flea. They are called water fleas because they live in fresh water and move with a jumping motion like a flea. They have swimming legs appendages that help them move rapidly through the water. They have eyespots. These help them move toward the light, but they can’t see clearly like we can. They eat other smaller organisms that live in the well-lit layers of the water.
Daphnia (Water Flea) eggs develop inside the body of Daphnia. The two round objects in the body of this Daphnia are the eggs.
When the eggs hatch, the young Daphnia (Water Flea) are squeezed out of the body of the mother.
Mayflies lay their eggs in streams. There are several stages of development that take place in the water. This is one of the larval stages that lives in the water. Mayfly larvae are a favorite food of fish and many fisherman use artificial mayflies on their lines to attract fish. If mayfly young are in a stream, it is a sign that the stream is healthy.
Eventually, the mayfly develops wings and flies. It lives for only a couple of days once it reaches this stage.
Adult damselflies lay their eggs in water. This is a picture of the damselfly nymph which is the young stage of the damselfly. It feeds on Daphnia, mosquito larvae, and other small organisms in the water. Damselfly nymphs are also a sign of a healthy stream.
When the nymph develops into the adult damselfly, it leaves the water and feeds on other insects and one type of damselfly even feeds on spiders.
Characteristics of life appropriate for this grade level include obtaining and using food, reproducing, growing and developing, and being organized. Many students will say that movement is a characteristic of life, but it is not a good example since there are living things that do not move and nonliving things that do move.
