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1. Polar bears can provide more food for Eskimos than seals can.
2. The total energy content of the seaweeds is lower than that of the seals.
3. Polar bear meat probably contains the highest concentrations of fat-soluble toxins.
4. Seals are more numerous than fish.
5. The carnivores can provide more food for the Eskimos than the herbivores can.

1. Biomass
2. Standing crop
3. Biomagnification
4. Primary productivity
5. Secondary productivity

1. Destruction of plant and animal habitats.
2. Erosion of soil due to increased water runoff.
3. Leaching of minerals from the soil.
4. Rapid eutrophication of streams and lakes.
5. Decreased carbon dioxide in the atmosphere.

1. Ecosystem augmentation.
2. Keystone species introduction.
3. Biological control.
4. Bioremediation.
5. Population viability analysis.

1. The ozone layer has been eroded by the release of chloroflourocarbons.
2. The ozone layer is thinnest at the equator.
3. Ozone caused by automobile emissions is slowly replacing lost ozone at higher atmospheres.
4. The release of pollutants from manufacturing sources had destroyed the ozone layer directly over major industrial centers.
5. Deforestation and "slash and burn" land clearing are responsible for most of the ozone layer depletion seen today.

1. Is useful in bioremediation of heavy metal pollutants.
2. Has been brought to the brink of extinction by nitrogenous runoff from farmland.
3. Is a major component of the marine food chain.
4. Causes fish and human disease in nitrogen-rich water.
5. May result in permanent memory loss in researchers.

1. CO₂ levels in the atmosphere have increased steadily over the last 30 years.
2. Greenhouse gases are capable of screening out harmful UV radiation from the sun which cause cancer in humans.
3. It has caused an increase in ambient temperature of the earth.
4. Burning tropical forests releases CO₂ into the atmosphere.
5. Destruction of primary producers in tropical regions increases the CO₂ in the atmosphere.

1. Secondary consumers require less energy than producers.
2. At each step, energy is lost from the system as a result of keeping the organisms alive.
3. As materials pass through ecosystems, some of them are lost to the environment.
4. Biomagnification of toxic materials limits the secondary and tertiary consumers.
5. Secondary consumers have a more general diet than primary producers.

Open-ended Questions on Ecosystem and Conservation Biology

1. Why do a pyramid of energy and a pyramid of biomass always have a larger “base” than tip?  (i.e. why is there more energy and biomass at the primary producer level than at the tertiary and quaternary consumer levels?) Energy flows through an ecosystem from its entry as light energy through primary producers (where it becomes chemical energy), through primary consumers, secondary consumer, tertiary consumers, etc.  At each level, some of the usable energy acquired from food is "lost" as heat, movement, or production of parts that are not digestible by the next tropic level.  This means that each successive trophic level has less energy available than the one before it.  Since there is less energy available at the upper levels, there are also fewer organisms at those upper levels, since there are not enough food organisms to support them.
2. Differentiate between a food chain and a food web.  Which is more likely to exist in nature? Food chains indicate that each organism has one set food source and serves as food source for one consumer.  In nature, many organisms are omnivores (feed at various levels) or switch levels of consumption depending on season and availability of food.  Multiple consumers may feed upon the same food source, and these multiple feeders and multiple food sources make a real trophic analysis diagram look more like a web than a chain.
3. Explain biological amplification of pathogens or pollutants through an ecosystem. Fat-soluble chemicals are stored in an animal's body after being consumed or absorbed from the environment.  When you go up the trophic levels, you find consumers who eat large numbers of smaller organisms, and all of the chemicals stored in each body are now concentrated in the fat of the one larger consumer.  Thus a chemical found in very low amounts in the abiotic components of an environment (soil or water) would be found in much higher amounts in in the bodies of secondary or tertiary consumers, often approaching toxic levels.
4. To what trophic level would a normal human belong?  omnivore A vegetarian? herbivore (primary consumer)
5. To what human activities is global warming directly tied?   What is the primary greenhouse gas involved? Burning, especially of fossil fuels, dumps CO2 into the atmosphere in higher amounts than naturally occurring.  Car emissions, electricity production at power plants, and other manufacturing contributes most of this CO2.  Removal of tropical rain forest producers also removes a means for removing gaseous CO2 from the air.  CO2 is considered the most important greenhouse gas due to its very long half-life in the atmosphere, and the fact that human activities easily create CO2.