Communities and Ecosystems

1. Communities and Ecosystems 1.01 Describe and compare several common ecosystems (communities of organisms and their interaction with the environment).

2. Community • A community is the interaction of all living things in an area. • Plants and animals are living things. Living things are sometimes called organisms. Staying closer together helps organisms better interact to survive. Microbes, like fungi and bacteria, are also living things that are part of a community.

3. Communities are made up of different populations of living things. A population is a group of the same type of organism existing in an area. Your neighborhood is made up of a population of humans. It is also made up of a population of crows. Or, let’s say mice, or perhaps grasshoppers. You see, there are hundreds of different populations that make up a single community. Each population relates with other populations in some way to form the larger community.

4. How is a Community Different from an Ecosystem? • A community is not the same thing as an ecosystem. An ecosystem is all the living things in an area AND their habitat. A habitat is a physical place where an organism lives; its shelter. Both living and non-living things make up an ecosystem. Plants, animals, water, soil, sunlight and air are all part of an ecosystem.

5. Ecosystems are everywhere. They can be as big as an ocean or as small as a puddle. Organisms are biotic factors in ecosystems. Non-living parts of an ecosystem are abiotic factors. Anytime biotic factors exchange matter or energy with abiotic factors—it is an ecosystem. Remember, an ecosystem is a system.

6. Just as ecosystems vary in size, so do habitats. Smaller or less mobile living things have smaller habitats compared to larger active organisms. Think about this for a second, a squirrel’s habitat is usually not much larger than a single square mile. But a black bear, on the other hand, can have a very large habitat covering many miles. An earthworm’s habitat would be smaller than a squirrel’s.

7. Ecosystems must meet the needs of organisms. Ecosystems most provide enough space, food and water for organisms. Many factors in an ecosystem can affect an organism’s survival. If there isn’t the right type of soil, or if the temperature is too hot or cold, certain organisms will not exist in that ecosystem. If an ecosystem cannot meet the needs of an organism, the organism will move or die.

8. Some Common Ecosystems • Let’s look at a few examples of some common ecosystems.

9. Tundra • The tundra is located near the north and south poles. Rainfall is light. Summer temperatures average only 1ºC (34ºF). The land in the tundra has poor soils that are almost always frozen. There are many lakes, ponds and bogs. Grasses are present but only a very few small trees growthere. The plants that grow there are mosses and lichens. Animals living in the tundra are reindeer, caribou, polar bears, arctic wolves, foxes, hares, lemmings, birds and insects.

10. Temperate Forest • The deciduous, or temperate, forest has variations in rainfall, but in general, the rainfall is medium. The average summer temperature is around 24ºC (75ºF). It has large and small trees that are broad-leaved with foliage that changes color in autumn. Trees such as oak, maple, red bud, tulip popular, pine and dogwood grow in this ecosystem. The animals found here are squirrels, deer, foxes, and bears. The state of North Carolina has some temperate forest ecosystems.

11. Grasslands • In general, the rainfall is low or very seasonal. The average summer temperature is 20ºC (68ºF). As the name implies, the dominant form of plant life found in this ecosystem is grass. Other types of non-woody plants can be found here. Plants like buffalo grass, sunflower, coneflowers, goldenrods, and clover thrive here. There are large herbivores on the savannas such as bison, pronghorn antelope, and zebras, as well as smaller ones such as burrowing rodents and prairie dogs.

12. Tropical Forest • The tropical rain forests have abundant rainfall and are very humid. The average summer temperature is 25ºC (77ºF). The trees are very tall with dense canopies. The floor of the tropical rain forest does not get much sunlight, but it does keep a fairly constant temperature. There are many species of both the plants and animals found in the tropical forest. Plants like vines, ferns, large and small trees and orchids live in the rainforest. Animals like orangutans, insects, sloths and jaguars also live in the rainforest.

13. Desert • Deserts get little rain and have extreme temperature fluctuations. The average summer temperature is 30ºC (86ºF). There is not much grass in the desert, but what is there is very drought resistant. Other plants, like sage-brush, mesquite and cacti, have also adapted to desert conditions. Animals common to the desert are the kangaroo rat, snakes, lizards, some birds, spiders and insects.

14. Aquatic Ecosystems • Aquatic ecosystems include freshwater areas, estuaries and marine areas all of which are determined by the saltiness of the water. Amount of light, oxygen, and the temperature are also important abiotic (non-living) factors of aquatic systems.

15. Freshwater • Freshwater ecosystems consist of streams, rivers, lakes, marshes, and swamps. All have low salt levels. Fresh water is an important nutrient to land plants and animals. It is also a major part of the water cycle. Freshwater ecosystems are found in areas with different temperatures and support a wide variety of animal and plant life.

16. Estuary • An estuary is a place where fresh and salt water meet in a coastal area. The salinity level in an estuary fluctuates, but it is generally not as high as in the ocean ecosystems. The water is partly surrounded by land with access to open ocean and rivers. Estuaries contain salt marshes and swampy areas and are biological diverse. This is because the tides circulate nutrients while removing wastes. There are many different types of unique plants and animals in estuaries. Estuaries are important for removing many water pollutants before emptying into the ocean.

17. Marine • Marine ecosystems include the ocean areas and seas. These waters have a very high salt content. They are warmer and have lots of sunlight near the surface of the water but get colder and darker the deeper the water gets. Coral reefs, tide pools, beaches, and the ocean floor are just a few examples of marine ecosystems. An abundance of plants and animals live in the ocean.

18. Review 1. What term best describes an ecostems? A. connected B. separate C. large D. small

19. 2. Which of the following is an abiotic factor in an ecosystem? A. trees B. bugs C. sand D. humans

20. 3. Which abiotic factor separates marine ecosystems from river ecosystems? A. sunlight B. salt C. sand D. algae

21. 4. Which sentence describes a habitat? A. Grass uses sunlight to grow. B. A mole lives underground. C. Bacteria break down dead plants. D. Deer eat forest plants.

22. 5. What is a community? A. a group of organisms living together B. an ecosystem C. non-living parts of a habitat D. living and non-living parts of a habitat

23. The End!!!