Question 1

If you are attempting to minimize the amount of mercury in your diet, you should eat:

Accepted Answer

Producers like fruits and vegetables have the lowest levels of mercury in the food chain.

Question 2

Chemicals that mimic the effect of reproductive hormones are:

Accepted Answer

Chemicals that mimic the effect of reproductive hormones are known as endocrine disruptors. They can interfere with the normal functioning of the endocrine system and have harmful effects on the reproductive system, as well as other systems in the body.

Question 3

Detritus feeders consume:

Accepted Answer

Detritus feeders, also known as decomposers or saprotrophs, consume dead organic matter. This includes dead plants and animals, as well as other organic materials such as feces and fallen leaves. They play an important role in nutrient cycling, breaking down organic matter into simpler forms that can be taken up by plants and other organisms.

Question 4

Autotrophs gain energy from:

Accepted Answer

Autotrophs, such as plants and algae, are able to produce their own food through photosynthesis using energy from the sun and inorganic nutrients.

Question 5

If a couple was attempting to get pregnant, which foods should they eat to avoid endocrine disruptors?

Accepted Answer

Organic grains, fruits, and vegetables are the best choice as they are grown without the use of endocrine-disrupting pesticides and chemicals.

Question 6

The three major reservoirs of carbon are:

Accepted Answer

The three major reservoirs of carbon include oceans, the atmosphere, and fossil fuels. The oceans contain dissolved carbon in the form of bicarbonate ions and dissolved carbon dioxide. The atmosphere contains carbon in the form of carbon dioxide, which is essential for photosynthesis in plants. Fossil fuels, such as coal, oil, and natural gas, are made up of carbon-rich organic matter that has been buried underground for millions of years.

Question 7

Which trophic level has the least bioaccumulation?

Accepted Answer

Primary producers (such as plants) generally have the least bioaccumulation because they are at the lowest trophic level and are the starting point of the food web. They may still accumulate some toxins or pollutants from the environment, but these are generally diluted across many individuals rather than being concentrated in a single organism. Heterotrophs, primary consumers, secondary consumers, and tertiary consumers are all higher up the trophic levels and are more likely to accumulate higher levels of toxins through biomagnification.

Question 8

Which nutrient cycle lacks an atmospheric reservoir?

Accepted Answer

Phosphorus cycle lacks an atmospheric reservoir. Unlike nitrogen, oxygen, carbon, and water, phosphorus doesn't exist in gas form in the atmosphere. It is found in rocks, soil, and sediments, and is cycled through the ecosystem via weathering, erosion, and biological processes.

Question 9

Carnivores are usually:

Accepted Answer

Carnivores are organisms that feed on other animals, making them secondary consumers in most ecosystems. Primary consumers are herbivores that feed on plants, while autotrophs are producers that make their own food. Detritus consumers feed on dead and decaying organic matter, and consumer producers are not a recognized ecological term.

Question 10

Net primary production is:

Accepted Answer

Net primary production (NPP) is the energy that photosynthetic organisms (autotrophs) make available to other organisms (heterotrophs) over a given period of time, after accounting for the energy used by the autotrophs for their own respiration.

Question 11

Certain bacteria and fungi that are important in nutrient recycling because they release nutrients from dead organisms back into the ecosystem are:

Accepted Answer

Decomposers, such as bacteria and fungi, break down dead organisms and release nutrients back into the ecosystem. This is an important process in nutrient cycling and maintaining the health and productivity of ecosystems. Autotrophs are organisms that produce their own food, carnivores eat other organisms, and detritus feeders consume dead organic matter without necessarily breaking it down into nutrients. Recyclers could refer to any organism involved in nutrient cycling, but decomposers specifically refer to the process of breaking down dead matter.

Question 12

In open-water marine ecosystems, the ________ occupy the same trophic level as the giant sequoias (redwoods)in the forests of California.

Accepted Answer

The giant sequoias in California are primary producers, occupying the first trophic level in the forest ecosystem. Similarly, in open-water marine ecosystems, the primary producers are microscopic, single-celled algae known as phytoplankton. They form the base of the food web and occupy the same trophic level as the giant sequoias.

Question 13

_______ is/are a crucial nutrient reservoir of phosphorus that is available to organisms.

Accepted Answer

Phosphorus is primarily stored in rocks and minerals, and is released through weathering and erosion over time. This makes rocks a crucial nutrient reservoir of phosphorus that is available to organisms. The atmosphere does not contain significant amounts of phosphorus, and while phosphorus is present in oceans and other bodies of water, it is typically not as readily available to organisms as the phosphorus in rocks. Autotrophs and consumers require phosphorus as a nutrient, but they do not serve as a reservoir for this nutrient.

Question 14

Bacteria that live in deep-sea thermal vents use energy from inorganic hydrogen sulfide (H2S)to make organic molecules from carbon dioxide and are thus:

Accepted Answer

Bacteria that use energy from inorganic sources to make organic molecules are producers in a food chain. Therefore, the bacteria living in deep-sea thermal vents that use energy from inorganic hydrogen sulfide to make organic molecules from carbon dioxide are producers.

Question 15

In a grassland of Kansas, 1,000 grams of grass are produced per square meter per year by all the different grass species. A theoretical upper limit to the biomass of secondary consumers that can be supported in this ecosystem is:

Accepted Answer

In an ecosystem, energy transfer between trophic levels is inefficient, with only about 10% of energy being passed on to the next level. Therefore, if 1,000 grams of grass (primary producers) are produced, the primary consumers (herbivores) could support about 100 grams, and the secondary consumers (carnivores) could support about 10 grams.

Question 16

Oceans, the atmosphere, and fossil fuels are large reservoirs of:

Accepted Answer

Fossil fuels are composed of carbon-rich organic materials that have been buried and transformed into coal, oil, and natural gas over millions of years. The oceans and atmosphere are also major reservoirs of carbon in the form of carbon dioxide.

Question 17

The community of heterotrophic protists and invertebrate animals, such as earthworms, pillbugs, mites, and pseudoscorpions, that live in the leaf litter on the shady floor of a deciduous forest obtains its energy and nutrients primarily from:

Accepted Answer

The community of heterotrophic protists and invertebrate animals in the leaf litter obtain their energy and nutrients through decomposition of the fallen leaves of deciduous trees. This is the primary source of organic matter in the leaf litter layer, which sustains the entire community.

Question 18

In 1956, people in Minamata, Japan, began to exhibit severe neurological disorders and birth defects. This problem was eventually attributed to methylmercury, a water-insoluble and breakdown-resistant chemical formed from mercury dumped into the adjacent bay by a local factory. People who ate which of the following seafoods would you expect were most affected?

Accepted Answer

Tuna that feed on smaller fish that feed on krill that feed on algae are at the top of the food chain and accumulate higher concentrations of methylmercury due to biomagnification. Therefore, people who eat tuna from contaminated waters are likely to have the highest levels of methylmercury exposure and be most affected by its neurological effects.

Question 19

Which of the following components is NOT involved in the phosphorus cycle?

Accepted Answer

The atmosphere is not directly involved in the phosphorus cycle, unlike the other options listed which all play a role in the movement of phosphorus through the ecosystem. Phosphorus primarily cycles through rocks, soil, water, producers, consumers, and decomposers.

Question 20

A snake that eats a small rabbit that feeds on grass is classified as a(n):

Accepted Answer

The snake is consuming the small rabbit, which is a consumer (feeding on grass), making the snake a secondary consumer. Autotrophs are organisms that produce their own food, primary producers are the first level of producers in a food chain, primary consumers are herbivores that eat the primary producers, and tertiary consumers are at the top of the food chain and eat other consumers.

Quiz 28: How Do Ecosystems Work