Set 14 - Ecology Part 3- Chapter 19 - Barron's

celine's version from 2018-03-06 18:12

Section 1

Question Answer
Water CycleWater evaporates form Earth, forms clouds, and rains over the oceans and land. Some rain percolates through the soil deeply enough to become groundwater. Some water evaporates directly from the land, bust most evaporates from plants by transpiration.
Carbon Cycle1. Cell respiration by animals and bacterial decomposers adds carbon dioxide to the air and removes oxygen. 2. The burning of fossil fuels adds carbon dioxide to the air 3. Photosynthesis removes carbon dioxide from the air and adds oxygen
Nitrogen Cycle1. Nitrogen-fixing bacteria live in the nodules in the roots of legumes and convert free nitrogen (N2) into the ammonium ion (NH4+) 2. Nitrifying bacteria convert the ammonium ion (NH4+) into nitrites (NO2-) and then into nitrates (NO3-) 3. Denitrifying bacteria convert nitrate (NO3-) into free atmospheric nitrogen (N2) 4. Decomposers are bacteria that break down dead organic matter, like dead plants and animals, into ammonia (NH4+)
The ways that humans have altered or destroyed many ecosystems;Deforestation of lands, Destruction of vast wetlands, Groundwater contamination and depletion, Elimination of habitats, and Loss of biodiversity.
Specific examples of how humans have altered Earth's ecosystem;1. Eutrophication of the lakes 2. Acid Rain 3. Toxins 4. Global Warming 4. Depleting the Ozone layer 5. Introduction of new species
process whereby excess levels of nitrogen or phosphorus cause excessive growth of microorganisms, depleting dissolved oxygen levels and kill ecosystem faunaEutrophication
Eutrophication of the lakesRunoff from sewage and manure from pastures increase nutrients in lakes and cause excessive growth of algae and other plants. Shallow areas become choked with weeds, and swimming and boating become impossible. As these large populations of photosynthetic organisms die, two things happen. First, organic material accumulates on the lake bottom and reduces the depth of the lake. Second, detritivores use up oxygen as they decompose the dead organic matter. Lower oxygen levels make it impossible for some fish to live. As more fish die, decomposers expand their activity and oxygen levels continue to decrease. The process continues, more organisms die, the oxygen levels decrease, more decomposing matter accumulates on the lake bottom, and ultimately, the lake disappears.
Acid RainCaused by pollutants in the air from the combustion of fossil fuels. Nitrogen and sulfur pollutants in the air turn into nitric, sulfurous and sulfuric acids, which cause the pH of the rain to be less than 5.6. This causes the death of organisms in lakes and damages ancient stone architecture.
ToxinsToxins from industry have gotten into the food chain. Most cattle and chicken feeds contain antibiotics and hormones to accelerate animal growth but may have serious ill effects on humans who eat the chicken and beef. Any carcinogens or teratogens (causing birth defects) that get into the food chain accumulate and remain in our body's fatty tissues.
Global warmingA gradual increase in the overall temperature of the earth's atmosphere generally attributed to the greenhouse effect caused by increased levels of carbon dioxide, chlorofluorocarbons, and other pollutants.
The process by which a planet is warmed by its atmosphere.greenhouse effect
Any gas, such as carbon dioxide or CFCs, that contributes to the greenhouse effect when released into the atmosphere.greenhouse gas
An example of disastrous effect of global warming that could happen on EarthAn increase of 1.0°C on average temperature worldwide would cause the polar ice caps to melt, raising the level of the seas and causing tremendous changes in weather patterns, including an increase in occurrences of violent storms. Eventually, major U.S. coastal cities, including New York and Miami could be under water.
Depletion of the Ozone layerThe accumulations in the air of chlorofluorocarbons, chemicals used for refrigerants and aerosol cans, have caused the formation of a hole in the protective ozone layer. This allows more ultraviolet (UV) light to reach Earth, which in turn is responsible for an increase in the incidence of skin cancer worldwide.
Any of a class of compounds of carbon, hydrogen, chlorine, and fluorine, typically gases used in refrigerants and aerosol propellants. They are harmful to the ozone layer in the earth's atmosphere owing to the release of chlorine atoms upon exposure to ultraviolet radiation.Chlorofluorocarbons
Introduction of new species Moving species from one area to another area. Example 1; Bringing African honeybees to Brazil to breed a variety of bee that would produce more honey than the Italian honeybee but they escaped and has been spreading throughout the Americas. In America, these bees hybridized with imported European or Western honeybees, giving rise to hybrid bees known as Africanised bees. These hybrids, along with native African honeybees and the descendants they gave birth in America, were colloquially named as killer bees because these killer bees caused human deaths. Example 2; Zebra mussel, a fingernail-sized mollusk, native to Asia, that was discovered in a Detroit lake. Scientists assumed that a ship carried it accidentally from Europe and without any local natural predator to limit, the population exploded. They clogged the water intake pipes of cities whose water is supplied by Lake Erie which caused millions of dollars in damage. They also threaten many indigenous species with extinction by out-competing them.

Section 2

Question Answer
Chemicals that kill organisms that humans consider undesirablepesiticides
Examples of pesticidesinsecticides, herbicides, fungicides, mice and rat killers
Negative effects of pesticidesExposure to pesticides can cause cancer in humans. Moreover, spraying with pesticides ensures the development of resistant strains of pests through natural selection. The pests come back stronger than before. This problem requires that we spray more and more, which means more people will be exposed to these chemicals.
An alternative to widescale spraying with pesticidesBiological control
A method of controlling pests such as insects, mites, weeds and plant diseases using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also involves an active human management role.Biological control
The four biological control options1. Crop rotation 2. Introduction of natural enemies to pests 3. Use of natural plant toxins 4. Use of insect birth control

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