Download Impact on Ecosystems Test Review

Impact on Ecosystems Test Review
1. Define the following:
a. Weathering - __breaking of rock/land into sediments; ice wedging, carbonic acids___________
b. Erosion - __movement of sediments by wind, water, gravity or glaciers__________________
c. Deposition - _dropping off of sediments in a new location like a sand dune________________
2. Rivers when they first begin are almost completely straight. Over time rivers develop more curves and
bends. Explain why this happens. _The moving water erodes the banks of the river. As the river curves
it slows down. The slowing down of the river causes deposition. The dropped sediments build up,
causing the river to curve even more._____________________________________________
3. Explain the process of ice wedging. Rain seeps into the cracks of rocks / cement / or a road. As the
temperature drops the water freezes. The water expands as it freezes. The expansion pushes the rock
apart and makes the crack bigger. The repeated rain, freezing, and thawing increases this effect._____
4. Vegetation helps to slow erosion. Explain 2 ways vegetation could slow erosion. Vegetation / plant
roots hold the soil in place; this reduces erosion by runoff. Trees trunks at the edge of a forest slows
the wind by blocking it.____________
5. Explain what abrasion is. Abrasion is a process that wears away by friction (like sand paper). Wind can
carry small sediments that can hit statues. Over time this could cause the words not to be readable.__
6. Classify the following as mechanical (M) or chemical (C)weathering:
Carbonic acid _C_
Animal burrowing _M_
Ice wedging _M_
Oxidation _C_
Plant roots _M_
Abrasion _M_
7. Texas has a variety of ecoregions that include coastal areas, prairie-grasslands, piney woods, and the
hill country. Each environment is changed by weathering, erosion, and deposition differently. Describe
how coastal areas, prairie-grasslands, piney woods, and the hill country are affected by weathering,
erosion, and deposition. (Rubric: 7 pts) Answers may vary… Coastal areas experience erosion by water
waves, and deposition on beaches and barrier islands. Prairie-grasslands would experience less erosion
by water than the coastal areas because it has more vegetation. The piney woods have trees that
would block wind erosion, some deposition of sediments could occur along the edge as wind slows
down. The hill country may experience weathering on the hills as rocks fall and are deposited at the
bottom.
8. Explain which of the following events are most likely to happen in Texas: flood, volcanic eruption,
hurricane, drought, earthquake, and tornado. Floods and droughts are possible in Texas because of our
extreme weather conditions. Tornadoes are possible in Texas, but most likely in the panhandle
because storms tend to meet there. Hurricanes after the coastal areas near the Gulf of Mexico.
Earthquakes and volcanoes do NOT happen in Texas because they only occur close to the edges of a
tectonic plate, like California or Hawaii.
9. What could an animal do to survive a catastrophic event? An animal could move to a new area to
search for food.
10. Describe how an ecosystem would be affected by a volcanic eruption that produced a cloud of ash that
lasted for six months. The extended period without sunlight would decrease the temperature, which
some plants/animals may not be able to withstand. Also the plants would not be able to go through
photosynthesis. If plants die, this could lead to animals dying.
11. Some catastrophic events can trigger other catastrophic events to occur. Explain 2 events that a
hurricane could trigger. A hurricane has a lot or rainfall. Huge amounts of rain could cause a flood. As
the soil is loosened by the water it could cause mud or landslides.
12. Ecosystems consist of the living and nonliving factors in the environment; including plants, animals,
land, and the atmosphere. Floods, hurricanes, and tornadoes are catastrophic events that impact
ecosystems. Describe how floods, hurricanes, AND tornadoes could impact an ecosystem. (Rubric: 6
pts) Answers may vary…Floods could increase pollution in the water which could cause plants and
animals to get sick or die. Hurricanes could wash away nutrients from soil and force animals to leave
their homes. Tornadoes increase the amount of dust in the atmosphere and can destroy buildings and
homes.
13. Draw a picture of a watershed. Label surface water, ground water, and water table.
Surface
Water
Ground
Water
Water
Table
14. Ground water levels do not stay constant. Explain 2 things the effect the amount of ground water
available, one that increases and one that decreases the amount of ground water available.
Increase ground water: rainfall
Decreases ground water: drought, high temperature, large population
15. Identify 2 positive and 2 negative human activities that could affect water in a watershed. Explain how
each of these could benefit or hurt the ground water and surface water. (Rubric: 8 pts) Answers may
vary… Human activities affect water in a watershed. Pesticides/insecticides can be infiltrated into the
ground and pollute ground water. Oil and waste water can contaminate surface water when runoff
carries it down a watershed. Humans can turn off the water when they are brushing their teeth or
water their lawns early or late to conserve the ground water supply. Humans can throw their trash
away so litter does not pollute the surface water.
16. Explain how fertilizer on a lawn could be harmful to a nearby lake. Runoff can cause fertilizer to be
eroded into the lake. Fertilizer increases the algae which blocks out the sunlight for plants found on the
bottom. This would cause the plants on the bottom to die and decay. As the bottom plants and the
algae decompose it takes oxygen out of the water. Fish nand other aquatic life need the oxygen in the
water to breathe and survive.