Changes in Texas Ecoregions Copy the questions and answers

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1 Changes in Texas Ecoregions Copy the questions and answers 1. What are some kinds of damage that hurricanes cause? Roads and bridges might be washed away. Trees and power lines can be knocked down. Area creeks and rivers overflow their banks. Low-lying lands may be flooded. Dirt and sand may be deposited on roads and lawns when flood waters recede. 2. Do you think the greater danger in hurricanes is from wind or water? The greater danger is from flood waters. Hurricanes push a high dome of water in front of them called a storm surge. The storm surge slams into the coast, washing away structures and flooding areas inland for miles. 3. What are some ways that people change the environment around them? People change the vegetation in an area by digging up native plants and planting non-native plants and crops. People also dig to build roads. We also cut down trees to clear land or make products from the wood. 4. Why is it important to know how the areas around us can be changed? We should learn about harmful changes so we can avoid making the same mistakes. We can also learn how our actions affect the land and water around us. 5. What's an ecosystem? An ecosystem is groups of organisms that interact with one another and with the nonliving environment around them. 6. Compare and contrast a marsh and a prairie. How are they alike and how are they different? They're both grasslands. But a prairie has tall grasses on dry land. A marsh is a zone of grasses in a wetland. 7. Explain why someone could say that a plain and a plateau are similar. Both are areas of flat or level land. 8. Why is climate important in defining an ecoregion? Plants are important organisms in an ecoregion. Climate helps determine what can grow in a particular area. 1

2 Gulf Coast prairies and marshes 9. Elia wants to build a house right on the beach along the Gulf. She says it will be strong enough to stand up to hurricane-force winds. Do you think Elia has a good plan for her house? Explain your answer. Elia's house may be able to stand up to strong winds, but that's only one issue with hurricanes and the beach. Sand along the beach moves due to erosion. Elia's house may not be a safe distance from the water over time. 10. Where does the river sediment that forms beaches come from? The sediment comes from eroded soil that enters rivers. 11. Does Gulf water cause fast or slow changes to Texas beaches? Explain your answer. The changes may be fast or slow. A hurricane can erode a beach in just a few hours. The movement of a barrier island or the building of a beach can take a long time. 12. Explain the difference between erosion and deposition. Then give an example of each at the shore. Erosion is the movement of sediment from one place to another. Deposition is the dropping or depositing of sediment. Washing away sand from a beach during a storm is erosion. A current dropping sand near a groin is deposition. Texas woodland ecoregions 13. You're an early settler in Texas. You can settle in either the Piney Woods or the Post Oak Savannah. Which would you choose and why? Some settlers might choose the Piney Woods because the forests would provide wood for building a house. Others might not choose it because they'd have to clear the land of trees to plant crops. Some settlers might choose the Post Oak Savannah because there's open land for planting crops, while there are also trees close by for building. 14. Do you agree or disagree with this statement: The Piney Woods is still largely forest, so there have been few changes to that ecoregion. Explain your answer. This is incorrect. Although the Piney Woods is forest, many trees have been cut down. This can lead to erosion. Dams in rivers in the Piney Woods have changed bottomlands as they get less water. 2

3 Prairie ecoregions 15. Where do the minerals in soil come from? Weathering and erosion of bedrock produces the mineral sediment in soil. 16. Why does marl soil resist erosion? Marl is clay that weathers quickly compared to other types of rock. It replaces eroded soil quickly so the soil remains deep even when some washes away. 17. Explain why deeper soils are affected less by erosion than shallow soils. Even after erosion, deep soils still have enough rich soil for plants to grow in. When soils are shallow, erosion quickly removes much of the good soil, leaving rocky subsoil or bedrock. Woodland and prairie changes 18. Why have people converted much of the prairie to other land uses? The prairie is level ground. Much of it has good soil. It's good land for growing crops. It's also easier to build on than woodlands or hilly areas. 19. Define the words "woodland" and "prairie". A woodland is an area where trees are the dominant plant. A prairie is an area where tall grasses are the dominant plant. High Plains ecoregion 20. Why is it important for farmers and ranchers to know how their crops and herds affect the land? Farmers and ranchers depend on the land for their crops and animals. They need to know when they may be harming the land so they can prevent harm or do the least damage. 21. Explain how better irrigation systems can conserve two important resources. Improved irrigation systems prevent soil erosion because they don't wash large amounts of water over the fields. They also waste less water. 3

4 22. You visit the Llano Estacado and see a playa, a sand dune, and a playa lake. Which one formed by wind erosion and deposition? Explain your answer. The sand dune formed when wind eroded sand and carried it to a new location. It then deposited the sand there. 23. Are plains all flat? Plains have a lot of flat land. But no land is completely flat. Parts of the plains have gently rolling hills. More plains ecoregions 24. How do the natural grasses of the High Plains and Rolling Plains differ? What do you think was responsible for the differences? The High Plains had short grass. The Rolling Plains had mixed grass. The most likely cause for the difference was the amount of rainfall and quality of the soil. 25. Why do you think that the Rolling Plains has so many cattle ranches? The climate is appropriate for cattle and the land grows many grasses. Grass is the food source for cattle. Changes to plains ecoregions 26. Describe a helpful and harmful effect of ranching in the plains ecoregions. The cattle are helpful because they provide food and resources. They also allow people to make a living. They're harmful because widespread grazing destroys native grasses. This leads to soil erosion. 27. Where are you if you're looking at a playa lake? How did the lake form? The High Plains has many playa lakes. Playa lakes are in depressions in the ground called playas. The playas formed when wind blew soil away. They become playa lakes when they're filled with rain water. 4

5 Edwards Plateau ecoregion 28. How do chemical weathering and mechanical weathering differ? Chemical weathering breaks rock down chemically. Mechanical weathering breaks it down physically. 29. Explain how karst landforms are related to erosion. Karst landforms form when slightly acidic water dissolves limestone rock underground. This is the process of chemical weathering. Trans-Pecos ecoregion 30. This ecoregion is a desert. What do you think the main characteristic of a desert is? The main characteristic of a desert is dryness, not heat. Deserts can be either hot or cold. Often, deserts receive fewer than ten inches of precipitation per year. 31. In the Trans-Pecos ecoregion, the actions of people have helped turn some areas from grassland into desert. Why is it important to study what has happened there? Studying what happened in the Trans-Pecos could help scientists learn enough to prevent it from happening elsewhere. Studying the Trans-Pecos could also help scientists learn how to repair some of the damage done to the ecoregion. More changes to ecoregions 32. Which process produces a more noticeable change to land, weathering or erosion? Weathering breaks down rock. But erosion moves the rock or sediment, which is a more noticeable change. 33. How are the changes to the Edwards Plateau and the Trans-Pecos alike? Grasses were an important plant cover in both ecoregions. Overgrazing helped destroy the natural plant cover in both places. 34. How does bedrock help characterize an ecoregion? Bedrock breaks down into sediment that becomes part of soil. The type of soil in an ecoregion helps determine the type of plants that can grow there. 5

6 Essential question review 35. Which ecoregion do you think has undergone the most change in the last 100 years? Explain your answer. One answer might be the Gulf Coast prairies and marshes. Much of the state's farming and heavy industry are in this ecoregion. A large part of the state's population is here, too. As a result, very little of it is left in its natural state. 36. Why are the changes in the woodlands different than those in other ecoregions? Many of the other ecoregions have changes associated with overgrazing, which lead to erosion. In the woodlands areas, especially the Piney Woods, most changes are due to logging of forest and the building of dams and reservoirs on rivers. 37. In which ecoregion has chemical weathering played an important role? Chemical weathering has played an important part in the Edwards Plateau, where it's helped form karst landforms. 38. What changes does the ocean water in the Gulf of Mexico bring to the Gulf Coast prairies and marshes? Ocean water moves sand in beaches and barrier islands, reshaping and shifting the shoreline. During storms, the pounding of waves causes severe erosion, flooding, and property damage for those who live at the shore. 39. How have cattle and other grazing animals changed Texas's ecoregions? Cattle destroyed native vegetation in several ecoregions. The dry, loose soil was then eroded by wind and water. 6