Ecosystems/Cycles part 2
The burning of coal, a fossil fuel, produces water and carbon dioxide. How is this similar to cellular respiration?
Both involve the breakdown of carbon compounds.
How do human beings contribute to the phosphorus and sulfur cycles?
adding chemical fertilizers to the soil
Sulfur and phosphorus compounds enter bodies of water, such as ponds, lakes, and rivers
as run-off containing fertilizers and detergents.
In order for matter to recycle and return in the food chain shown here, what must be present at level A?
decomposers
Consider the diagram of the water cycle. Assume we have a very cold winter with lots of snow. The mountain top is piled high with snow. Then it is spring. How will this impact the water cycle model?
ground water will increase
Consider the model of the oxygen cycle on Earth. The majority of Earth's oxygen reservoirs are found in the
lithosphere.
According to the law of conservation of matter, in any food chain we know that
matter is changed into various forms but the total quantity remains unchanged.
In the energy pyramid, if a primary producer is consumed by a first-level consumer, and that first-level consumer is consumed by a second-level consumer and the second-level consumer is consumed by a third-level consumer, how much energy is stored by the third-level consumer from the primary producer?
0.1%
Consider this ecological pyramid found in the Great Lakes ecosystem. Ecological pyramids are diagrams that are used to show how much energy, the number of organisms, or how much biomass may be found at each trophic level of all the food webs of a community. Why are the autotrophs, in this case the algae, always placed at the base of the pyramid?
Autotrophs are responsible for converting solar energy into usable chemical energy.
Consider this system, a food web. The majority of energy
is lost from the system as heat energy
This food chain is incomplete. Two groups of organisms are missing. One group of organisms that is missing are the producers, plants and other photosynthetic organisms. They turn sunlight into chemical energy. What is the other missing group and what do they do?
Decomposers that recycle matter back into the food chain.
In a food chain 90% of the energy is lost in the transfer at each trophic level, and only 10% passes as usable biological energy. What will happen if secondary consumers are removed from a food chain?
Energy transfer to the subsequent trophic levels of the food chain will be disturbed.
The snake does not get as much energy from eating the same amount of food as the grasshopper. The statement that best explains why this is true is
Grasshoppers use up much of their energy for life processes.
What happens to any matter that is not used by consumers in a food chain?
It is decomposed by decomposers and brought back into the food chain later.
This is a typical grassland food web. It is also a small picture of an important cycle on Earth: the carbon cycle. Describe how the carbon gets into this food web.
Plants use carbon dioxide as a reactant in photosynthesis, to make usable chemical energy in the form of a sugar.
The diagram above shows a pyramid of numbers for a Jack pine forest community. The number of producers is much lower than those of the primary consumers. How can this be?
The biomass of trees is much greater than smaller producers, like grasses and shrubs. One tree can support many primary consumers.
What is the MOST LIKELY effect on the energy pyramid if all producers are removed from the ecosystem?
The energy pyramid will be completely disturbed.
Look at the diagram of the food web. Fungi and bacteria are at the bottom of the food web. What would MOST LIKELY happen to the grass if most of the fungi and bacteria die?
The grass will not grow as well.
Which statement correctly describes the diagram?
The products of respiration can be used by plants for photosynthesis.
A food web in a certain ecosystem consists of seals that feed on krill, which in turn feed on phytoplankton. Extensive krill fishing reduces the krill population rapidly. What would be observed in the ecosystem as an immediate effect of this?
The seals would decrease in number and the phytoplankton would increase in number.
The process of photosynthesis is essential in the oxygen/carbon dioxide cycle. Photosynthesis removes ______ from the atmosphere and produces and releases ______ into the atmosphere.
carbon dioxide and oxygen
In a typical energy pyramid about 10% of the available energy is transferred from one trophic level to the next. Consider an area in which the energy production of the autotrophs equals 200 Kcal/m2/year. What is the amount of energy available to secondary consumers in this energy pyramid?
2 Kcal/m2/year
Using the model, calculate how much carbon, in g/m2, will be passed from the grasshopper to the decomposers.
55 g/m2
There is much interdependence among the biogeochemical cycles on Earth. How is warmer ocean water involved in these cycles?
Atmospheric carbon dioxide, a greenhouse gas, would cause rising ocean temperatures, which will cause an increase in evaporation. The added water vapor would further increase global warming.
What is the BEST conclusion that can be drawn? I. All the energy contained within the organisms in the web comes from the sun. II. The energy from the caterpillar is transferred to the plant. III. The hawk is the top predator. IV. Energy is transferred from organism to organism in this food web. V. The bunny is the organism that harnesses the energy from the sun.
I, III, and IV only
Describe the role of plants in the movement of water through the water cycle.
Plants absorb water and release back into the atmosphere through transpiration.
Phosphorus is an essential nutrient for plants and animals. Phosphorus normally occurs in nature as part of a phosphate ion (PO4)3. As you can see from the diagram of the phosphorus cycle, unlike many other biogeochemical cycles, the _____________ does/do not play a significant role in the movement of phosphorus.
atmosphere
Some of the characteristics of _________ are listed. These characteristics result in the formation of millions of organic compounds, many of which are synthesized and found within cells.
carbon
In any food web, plants are considered to be producers. They convert sunlight (solar energy) into usable chemical energy (glucose). When we eat plants our bodies are using that chemical energy. What elements are rearranged to make glucose in plants?
carbon, hydrogen, and oxygen
Solar radiation travels through the earth's atmosphere and warms the planet's surface. Greenhouse gases like carbon dioxide in the earth's atmosphere reabsorb the heat and warm the planet. The amounts of greenhouse gases have been increasing over the past century, causing the earth's surface temperature to increase. This gradual temperature change is thought to have many negative environmental consequences. Which of these might be a POSITIVE effect of the increase in carbon dioxide levels?
increase in plant growth
Carbon dioxide is constantly exchanged among the atmosphere, ocean, and land. Carbon dioxide is produced and absorbed by microorganisms, plants, and animal by natural processes which help maintain a natural balance. However, since the beginning of Industrial Revolution, human activities have contributed substantially to Carbon dioxide gases in the atmosphere. Which conclusion might be drawn between the relationship found in the graphs of Global Carbon Emissions and Global Temperatures over the past 150 years.
increased Carbon emission from human activities are directly correlated to increased global temperatures
The process of respiration is essential in the oxygen/carbon dioxide cycle. Respiration removes ______ from the atmosphere and produces and releases ______ to the atmosphere.
oxygen and carbon dioxide
Solar energy is utilized to convert inorganic carbon, in the form of carbon dioxide, into organic carbon compounds, such as glucose. This is part of the carbon cycle on Earth; a cycle which demonstrates the law of conservation of matter. What process is responsible for inititating this cycle?
photosynthesis
Carbon dioxide is constantly exchanged among the atmosphere, ocean, and land. Carbon dioxide is produced and absorbed by microorganisms, plants, and animal by natural processes which help maintain a natural balance. However, since the beginning of Industrial Revolution, human activities have contributed substantially to Carbon dioxide gases in the atmosphere. Identify the type of relationship found in the graphs of Global Carbon Emissions and Global Temperatures over the past 150 years.
positive nonlinear correlation
A plant absorbs 200 J/g of energy from the sun. A cow eats the plant and absorbs 120 J/g of energy. The cow is fed to a group of humans who absorb 70 J/g from the meat. What is the main reason the energy consumption decreases from one consumption to the next?
some enregy is wasted as heat
An energy pyramid is a graphical model of energy flow in a community. The different levels represent different groups of organisms that compose a food chain. An energy pyramid's shape shows how the amount of useful energy that enters each level. Chemical energy, in the form of food, decreases because some is used by the organisms in each level. The source of the chemical energy is the producers, that rearrange carbon dioxide and water in the presence of light to make ________ through the process of ______________.
sugars; photosynthesis
Above is an example of a food chain or pyramid. Ultimately, either directly or indirectly all organisms on this food chain get their energy from what single source?
the sun
Plant cells undergo photosynthesis to produce glucose, a usable form of chemical energy. The energy produced by plants becomes the base of an energy pyramid. Given the situation seen above, what reactant is missing in order for photosynthesis to occur?
water
There are several models of the carbon cycle. Which model shows the causes and amounts of carbon flux into and out of the cycle?
A) A
Food webs - transferring energy and matter from one level to another. Consider the food web you see here. Would you change this food web to make it more accurate? If yes, how?
Add the Sun; the source of energy. Add a decomposer also like fungi.
What statement holds true for the amount of matter in a successful food web?
Amount of matter produced by the producers should be more than that of the consumers.
Rivers, springs, and aquifers are all fresh water components of the hydrologic cycle. As this water progresses through the cycle, it will eventually ___________ into the atmosphere before ____________ and falling back to the earth as precipitation.
evaporate; condensing
We consider the water cycle to act as a system. Outputs in this system would be
evaporation and transpiration.
Look carefully at the model. Plants take in and release carbon dioxide. Plants take in carbon dioxide for photosynthesis. What process releases carbon dioxide back into the atmosphere?
respiration
Organisms are constantly interacting with their environment. Sometimes this interaction has a positive effect on the environment, other times a negative impact. Beetles in the forest infest and eat limbs of trees that have fallen to the forest floor. The best way to describe the beetles impact is to say that
they are having a positive impact on the environment by acting as decomposers.
Like animals, plants undergo cellular respiration to produce energy. Plants use oxygen and release carbon dioxide and water. Water returns to the atmosphere and becomes part of the water cycle through the process of
transpiration
Look carefully at the model. Plants take in the increased ground water and use the water for photosynthesis. Plants also release water into the atmosphere as a by-product of cellular respiration. What process returns the water to the water cycle (#5 in diagram)?
transpiration
Consider the diagram of the water cycle. Assume that deforestation has taken place. How will this effect the movement of water through this model?
transpiration will decrease
Look carefully at the model. During a drought, there is less water available for the plants. There is less runoff and less infiltration. During a drought, less water is returned to the atmosphere by the plants through __________, and there is a decrease in the plants' rate of ___________.
transpiration; photosynthesis
Consider the biomass of the Jack pine trees in this pyramid. If the biomass of one Jack pine equals 12000 kg/m2/year, than what is the predicted biomass of the tertiary consumer level?
12.0 kg/m2/year
This is a typical grassland food web. It is also a small picture of an important cycle on Earth: the carbon cycle. Man can impact the carbon cycle in a negative way. All but one example below would negatively impact the carbon cycle. Identify it.
Planting a field of wheat
Plants need both sulfur and phosphorus in order to grow and reproduce. How do plants obtain sulfur and phosphorus?
Plants absorb sulfates and phosphates present in the soil through their roots.
Oxygen, the element, is recycled in a biogeochemical cycle within its three main reservoirs: the atmosphere, the total content of biological matter within the biosphere, and the Earth's crust. The driving force of the oxygen cycle is photosynthesis, which is responsible for modern Earth's atmosphere and life on Earth. Using the data collected, hypothesize as to which reservoir contributes least to the recycling of oxygen from year to year. Explain.
Lithosphere. Although the lithosphere is the greatest oxygen reservoir, it has the lowest amount of flux and the highest residence time.
Consider this ecological pyramid found in the Great Lakes ecosystem. Ecological pyramids are diagrams that are used to show how much energy, the number of organisms, or how much biomass may be found at each trophic level of all the food webs of a community. Note that the autotrophs are always placed at the base of the pyramid. Why are the saprotrophs and detritivores are placed to one side of the pyramid?
Nutrients and some of the energy from all other levels passes through the saprotrophs and detritivores when other levels die or leave wastes behind.
Carbon dioxide is naturally present in the atmosphere as part of the Earth's carbon cycle. Human activities are altering the carbon cycle, by adding more CO2 to the atmosphere and by influencing the ability of natural sinks, like forests, to remove CO2 from the atmosphere. While CO2 emissions come from a variety of natural sources, human-related emissions are responsible for the increase that has occurred in the atmosphere since the industrial revolution. Consider the graph above. Notice the trend in atmospheric carbon dioxide as recorded at recording stations over Antarctica. Hypothesize how the schematic of the carbon cycle might change if urbanization and deforestation continues unchecked.
The photosynthesis carbon sink will decrease in gigatons; the carbon dioxide output due to combustion will increase.
Food webs - transferring energy and matter from one level to another. Here you see four food webs. One or more are incorrect. Which food web(s) show the correct sequence of organisms, from start to top level consumer?
b and c
Review the image of the nitrogen cycle. Nitrogen is an important element needed for plant growth. What living organism plays a big role in adding atmospheric nitrogen to the soil?
bacteria
According to the law of conservation of matter, matter is never created or destroyed. Yet in a food pyramid the amount of biomass decreases as we move up through the pyramid, from producers to top level consumers. Why?
Matter changes to other forms that might not continue to be a part of the same food chain.