Environments and Ecosystems

Transcription

1 Environments and Ecosystems A habitat is a place where organisms naturally live and grow. Habitats include biotic, living factors, such as plants and animals and abiotic, non-living factors, such as rocks, water, and air. A habitat can be as large as a biome such as a desert, forest, or tundra. Biomes can be divided into microhabitats, small, specialized habitats. For example, a garden can be considered a microhabitat and can include even smaller microhabitats such as a rotting log, a clump of grass or even a space between rocks. A variety of organisms live in these microhabitats, where they interact with different biotic and abiotic factors (resources) such as water, food, and shelter. Microhabitat - ant hill Background Large habitat -ocean biome Environments and Ecosystems Biodiversity is a shortened term for biological diversity, and it can be observed and measured on a large scale such as in the ocean or a national park, or on a smaller scale, such as in a microhabitat. The level of diversity is determined by defining a specific area and recording the interaction between the varieties of organisms present. Entire species, populations, and individual organisms are directly and indirectly dependent on their environment. Thus, if environmental conditions change, the changes will affect the plants and animals of the area. The sustainability of a habitat or biome is the ability of that area to maintain itself in the face of outside factors such as natural catastrophes like tornados, flood, pollution, or disease. The greater the biodiversity in an area, the healthier and more sustainable it will be. Biodiversity keeps life in balance and healthy on Earth. A community is all the different organisms that live together in an area. A community in a habitat is in a state of balance when the number and species of organisms in it do not change suddenly. Events such as fires, floods, volcanoes, and hurricanes disrupt the equilibrium of a community by changing it drastically in a short period of time. But even without a disaster, communities sometimes change. Succession is the series of predictable changes that occur in a community over time. After a fire, flood, volcanic explosion, or human activities, succession enables a habitat to recover. Please answer the background questions in your Student Journal. 1

2 Part I: Biomes A biome is one of the world s major communities, classified according to the predominant vegetation and characterized by adaptation of organisms to that particular environment. In other words, a biome is a large habitat with a certain climate and land formations that lead to the growth of plants adapted to the area which in turn support the other organisms that live there. Scientists don t agree as to the exact number and types of biomes but the most commonly accepted are freshwater, marine, forest, grassland, desert, and tundra. Biomes are found all over the globe. Look at the map of world biomes provided by your teacher in the Student Reference Sheet. You may look at the map of biomes and think, the eastern United States is not a forest! When assigning a biome type, scientists use the process of succession. Succession is the change in types of species present in a community over time such as after a disturbance. In other words, if New York City was evacuated and all of the buildings were removed to allow the land to return to its natural state, the land would eventually become a forest. The area would remain a forest until a disturbance such as a fire or human construction occurs. Step One: Research the biome assigned to you by your teacher, make a slide show and present your biome to your class. Use the notes section in your Student Journal to organize the research information for your presentation. Your presentation must include the following: Type of biome Climate of the biome Abiotic features of the biome (soil type, geology or land forms, water resources) Biodiversity of the biome (the organisms commonly found there) Step Two: Take notes in your Student Journal during the presentations of each biome. Your notes must include: Type of Biome, Climate of the biome, Abiotic features of the biome, Biodiversity of the biome. Complete Part I in the Student Journal. 2

3 Part II: Biodiversity Biodiversity is the number of different species of plants and animals that live in an area. The biodiversity of a habitat is important for the survival of the organisms that live there. The more plants there are, the greater the variety of food sources for organisms that feed on plants. If one plant species dies due to drought or disease, plant eaters have alternative things to eat. The same is true for the organisms that eat meat. The greater the number and variety of animals there are in the area, the easier it is for a meat eating animal to find a meal. Round 1 1. Your teacher will give every student an index card. 2. Write Douglas Fir (a type of tree) on one side. 3. When your teacher tells you to, walk around the room and have three students who are not sitting at your table write their first name on the back of the card. 4. When you have three names have a seat and follow your teacher s directions. 5. After the activity answer the questions in your Student Journal. Round 2 1. Your teacher will give out an index card to every student and tell you what type of tree to write on it. They will all be different, so listen carefully. 2. When your teacher tells you to, walk around the room and have three students who are not sitting at your table write their first name on the back of the card. 3. When you have three names have a seat and follow your teacher s directions. 4. After the activity answer the questions in your Student Journal. Answer the questions in Part II of your Student Journal. 3

4 Part III: Succession in Microhabitats We have learned about the many different biomes that cover the earth. These habitats include all of the abiotic factors needed for organisms to compete for living space and food. Within each biome there are many microhabitats (micro meaning small) that support a few organisms at a time. These microhabitats can be disturbed by natural events and by human activities. When these microhabitats are disturbed they try to reestablish their balance through a process known as succession. Succession is the series of changes that occur after a disturbance in an existing habitat. Natural disturbances that have this effect include fires, hurricanes, and tornadoes but human activities can also cause disturbances to habitats. Before buildings are constructed the surrounding area must be cleared of trees, grasses, weeds, and other plants. After the building is erected the area around it must be maintained or the original plants will start to grow again. This is an example of succession. 1. Observe the four pictures from the Teacher Printout: Succession in a Microhabitat. 2. Cut them out and place them in order from first to last. 3. Glue them into your Student Journal. 4. Continue writing the story that was started for picture 1. Answer the questions for Part III in your Student Journal. 4

5 Part IV: Succession after a Forest Fire Disasters such as forest fires kill many plants and animals in a habitat very quickly. Forest fires start by natural causes or by humans. Lightening is the most likely natural cause of fires. On average, more than 100,000 wildfires clear 4-5 million acres of land in the United States every year. A wildfire can move at speeds up to 14 mph, consuming everything in its path, including trees, bushes, flowers, grasses, animals and buildings. Forest fires can have helpful effects. They release nutrients that are good for the growth of some plants. After a forest fire, succession helps the habitat recover. 1. Read the story of the aftermath of a forest fire. 2. Match the pictures to the descriptions in the story. 3. Glue the pictures in the correct place in your Student Journal. Complete Part IV in your Student Journal. 5