Environmental Contribution. QuestionPart 1 of 1 –
Question 1 of 25
4.0 Points
Which of the following people is INCORRECTLY matched with his/her environmental contribution?
A.Rachel Carson: Silent Spring
B.John Muir: Sierra Club
C.Paul Ehrlich: The Population Bomb
D.Theodore Roosevelt: Civilian Conservation Corps
Part 1 of 1 –
Question 2 of 25
4.0 Points
DDT was sprayed in a Long Island salt marsh over a period of years for mosquito control. A portion of the food web is as follows:
algae -> shrimp-> American eel -> Atlantic needlefish -> ring-billed gull
In which organism would biological magnification be MOST evident?
A.American eel
B.Ring-billed gull
C.Algae
D.Shrimp
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Question 3 of 25
4.0 Points
Which of the following statements about biogeochemical cycles is true?
A.They only include processes conducted by or within living organisms.
B.They pertain only to the abiotic environment.
C.They describe the movement of water and other materials through an ecosystem.
D.They only pertain to exchanges and interactions that occur within the atmosphere.
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Question 4 of 25
4.0 Points
Which of the following would be a symptom of acute toxicity?
A.asthma
B.arthritis
C.dizziness
D.cancer
Part 1 of 1 –
Question 5 of 25
4.0 Points
Which of the following series is organized in successive steps according to the levels of organization used by ecologists?
A.population -> ecosystem -> community
B.population -> community -> ecosystem
C.species -> community -> biosphere
D.species -> ecosystem -> population
Part 1 of 1 –
Question 6 of 25
4.0 Points
Corporations and governments began to take NEPA seriously after which of the following events?
A.Further legislation was added to strengthen NEPA.
B.The publication of Rachel Carson’s book Silent Spring.
C.The creation of the EPA.
D.Environmental groups began suing individuals and organizations based on environmental impact statements.
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Question 7 of 25
4.0 Points
This figure BEST illustrates:

Graphic
A.how our atmosphere maintains its temperature.
B.how energy is recycled in an ecosystem.
C.the one-way flow of energy in an ecosystem.
D.the importance of decomposers in an ecosystem.
Part 1 of 1 –
Question 8 of 25
4.0 Points
The most common method of determining whether a chemical causes cancer is to expose groups of laboratory animals, such as rats, to various large doses and count how many animals develop cancer at the different levels. All of the following are problems with this approach in terms of understanding the health risks to humans EXCEPT:
A.This method is indirect and uncertain as human and rats are different organisms and may respond differently to exposure to the same chemical.
B.For expediting the research process, in lab settings rats are exposed to massive doses of suspected carcinogens relative to body size whereas humans are usually exposed to much lower amounts.
C.For ethical reasons, rats in lab settings are given very small doses of suspected carcinogens relative to body size whereas humans are usually exposed to much higher amounts
D.Risk assessment assumes that we can extrapolate from studies in rats to determine the expected rates of cancer in humans but extrapolating from one species to another and from one dose level to another is uncertain and may overestimate or underestimate a toxicant’s danger.
Part 1 of 1 –
Question 9 of 25
4.0 Points
How might the clearing of roads and pristine areas like the one shown below lead to an increase in infectious disease?
Graphic
A.Cars on the road can carry the diseases to cities.
B.Typhoid and cholera can spread from wild animals to drinking water.
C.The creation of drainage ditches provides habitat for disease carrying mosquitoes.
D.There is an increased risk of sewage leaking into the water supply.

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Question 10 of 25
4.0 Points
Which of the following statements BEST describes emerging diseases like swine flu?
A.Infectious diseases that were not previously found in humans and typically jump from an animal host to humans.
B.Infectious diseases that existed in the past but for a variety of reasons are increasing in incidence.
C.Infectious diseases that were previously found in humans and typically jump from a human host to animals.
D.Non-infectious diseases that have transformed into infectious diseases.
Part 1 of 1 –
Question 11 of 25
4.0 Points
Which of the following statements about dose-response curves is FALSE?
A.A dose-response curve shows the effect of different doses of a toxicant on a population.
B.Doses lower than the threshold level will have no measurable effect on organisms.
C.The smaller the LD50, the more toxic the chemical.
D.Studies of the dose-response curves of toxicants gives us assurance that for all chemicals there is a threshold level of the chemical so small amounts of chemical pollution pose no health risks
Part 1 of 1 –
Question 12 of 25
4.0 Points
Who wrote Man and Nature, one of the first books discussing human impact on global environmental change?
A.Paul Ehrlich
B.Rachel Carson
C.George Perkins Marsh
D.John Muir
Question 13 of 25
4.0 Points
Chemical A has a toxicity level of 1 and chemical B has a toxicity level of 2. If a mixture of the two chemicals has a toxicity level of 4, what can we say about the results of the mixture?
A.it was additive.
B.it was persistent.
C.it was synergistic.
D.it was antagonistic.
Part 1 of 1 –
Question 14 of 25
4.0 Points
Which of the following criticisms or backlash against the environmental movement in the 20th century are TRUE?
1. In the late 1990s some conservative research groups criticized what they perceived as a biased presentation of environmental issues, particularly the promotion of environmental activism, in schools.
2. Many economists such as Julian Simon have countered the dangers of overpopulation by pointing out that technological advances outpace the negative impacts of population growth.
3. Most of the world’s religions have rejected environmental themes by pointing out that such ideas are contrary to their religious teachings.
a) 1 only
b) 2only
c) 3 only
d) 1 and 2
A.1 and 2
B.2 only
C.1 only
D.3 only
Question 15 of 25
4.0 Points
Which of the following processes plays an important role in the phosphorus cycle?
A.erosion
B.nitrogen fixation
C.combustion
D.cellular respiration
Question 16 of 25
4.0 Points
The nitrogen cycle is one of the most important and complex of the biogeochemical cycles. Why is nitrogen important?
A.It’s an Ozone depleting gas.
B.It’s an essential part of biological molecules such as proteins and nucleic acids (DNA)
C.It’s the most toxic element to living organisms
D.Nitrogen dilutes the oxygen in the atmosphere causing respiratory problems

Part 1 of 1 –
Question 17 of 25
4.0 Points
Herbivores are:
A.primary consumers
B.secondary consumers
C.decomposers
D.scavengers
Part 1 of 1 –
Question 18 of 25
4.0 Points
Which of the following statements about malaria is FALSE:
A.Road clearing in the Amazon has disrupted the natural environment and created habitat for the mosquito larvae to thrive.
B.Mosquitoes do not cause malaria but are the agents of transmission of the disease.
C.It is a non-transmittable disease caused by synthetic chemicals.
D.It is an infectious disease caused by a protozoan parasite.
Part 1 of 1 –
Question 19 of 25
4.0 Points
Which of the following would environmental economists consider natural capital?
A.Water purification by a cattail marsh.
B.A water treatment facility.
C.Increased agriculture made possible by irrigation.
D.A severe hurricane like Katrina.
Part 1 of 1 –
Question 20 of 25
4.0 Points
The soil conservation service was formed after what environmental crisis?
A.soil contamination by toxic waste at love Canal in the 1970s.
B.severe erosion following windstorms in the 1930s.
C.mudslides in California following the San Francisco Earthquake in 1906.
D.severe erosion following forest fires in Yellowstone National Park in the 1980s.
Part 1 of 1 –

Question 21 of 25
4.0 Points
Photosynthesis is:
A.A physical law, which states that when energy is converted from one form to another, some of it is degraded into heat, a less usable form that disperses into the environment.
B.The biological process that captures light energy and transforms it into the chemical energy of organic molecules, which are manufactured from carbon dioxide and water.
C.The measure of the amount of usable energy available to do work in the universe.
D.The process that involves potential energy being converted to kinetic energy.
Part 1 of 1 –
Question 22 of 25
4.0 Points
National income accounts are incomplete estimates of national economic performance because national income accounts do NOT include
A.gross domestic product
B.net domestic product
C.estimates of imported goods and services
D.estimates of external costs such as natural resource depletion and the environmental cost of economic activities
Part 1 of 1 –
Question 23 of 25
4.0 Points
Which of the following is an endocrine disrupter?
A.CFCs
B.mercury
C.ozone
D.carbon dioxide
Part 1 of 1 –
Question 24 of 25
4.0 Points
We measure toxicity by the dose at which adverse effects are produced. Which of the following statements about the dose of and response to toxic agents are true?
A.Lethal doses of particular toxicants for humans are known through doing laboratory tests on human subjects.
B.Doses are expressed in milligrams of toxicant per kilogram of body weight.
C.Sub-lethal doses usually produce acute toxicity whereas lethal doses produce chronic toxicity.
D.Response to a dose depends only on the type of toxicant and not the age or health of the organism.Reset Selection
Part 1 of 1 –
Question 25 of 25
4.0 Points
Why have some plants evolved mutualistic relationships with nitrogen-fixing bacteria?
A. The bacteria utilize nitrogen to produce energy for the plants; the plants provide the source of the nitrogen for the bacteria.
B. The bacteria transform nitrogen into forms useful forms for the plants; the plants provide water and a place for the bacteria to live.
C. The bacteria protect the plant from harmful effects of nitrogen compounds such as ammonia; the plants provide carbohydrates for the bacteria.
D. The bacteria provide natural immunities to the plants; the plants shelter the bacteria from predators.

Environmental Contribution

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Lab 05: Photosynthesis. To submit this assignment, students will complete the Lab Worksheet on pages 7-10, then upload their completed document as a DOC or PDF file in Canvas

BIO 101 Lab 08: Photosynthesis

Notification: If you have a disability that makes it difficult to complete this lab, please contact your instructor. Please provide your instructor a copy of the Memorandum of Accommodation (MOA) from NVCC Disability Support Services.

Objectives:________________________________________________________________

· Determine the effects of light on the rate of photosynthesis

· Determine the absorption spectrum of leaf pigments

Background:_______________________________________________________________

Sunlight provides the majority of energy for organisms living in most ecosystems, however only a subset of organisms are capable of harvesting this energy. Plants use their chloroplasts to absorb the energy from sunlight. This energy is then stored in the covalent bonds of glucose, a simple sugar, and can be used by the plant for structural purposes (cellulose), as usable energy (ATP generation), or for energy storage (starch). Animals can eat plants to obtain glucose and produce energy through a process called cellular respiration.

The overall reaction for photosynthesis is represented by the chemical equation:

6 CO2 + 6 H2O + sunlight → C6H12O6 + 6 O2

The entire process is complex and involves many enzymatic reactions. You may notice that the photosynthesis reaction is nearly the exact reverse of cellular respiration. From the equation above the three key elements for photosynthesis to occur are carbon dioxide (CO2), water (H2O), and light. If any of the three are missing from the system then photosynthesis will not occur, and glucose production in the plant will be negatively affected.

There are two phases of photosynthesis: 

1) In the light-dependent phase chlorophyll molecules located in the thylakoid membrane stacks of the chloroplasts absorb the energy from light resulting in the production of ATP and NADPH.

2) In the light-independent reactions (the Calvin Cycle) the energy stored in ATP and NADPH is used to ultimately convert carbon dioxide to sugar. The process of taking carbon dioxide from the air to build carbohydrates is called carbon fixation.

In solution, CO2 can be converted to carbonic acid (H2CO3) when dissolved in water. The carbonic acid will then release hydrogen ions (H+), causing the pH of the solution to decrease.

CO2 + H2O H2CO3 HCO3- + H+

Bromothymol blue is a pH indicator that changes color based on the pH of a solution. Bromothymol blue turns yellow at lower pH and blue as the pH is increased. This indicator can be used to track respiration (turns yellow as CO2 is added to the system) or photosynthesis (turns blue as CO2 is consumed).

Different colors of Bromothymol blue at the indicated pH conditions

Light energy is a small part of the electromagnetic spectrum which is visible to the eye. The wavelength of visible light lies between 380 nm and 760 nm. In order to obtain the energy from light, plants must absorb light energy using pigments, namely chlorophyll a, chlorophyll b, carotene and xanthophyll. These pigments show characteristic colors because they do not absorb all light equally. By measuring the absorbance at different wavelengths, the absorption spectrum of the leaf pigments can be obtained.

Materials:__________________________________________________________________

Safety:

Follow all standard laboratory safety procedures.

Procedure:________________________________________________________________

Experiment 1. Observing photosynthesis (work in groups)

1. In the laboratory, you would add about 60 ml of tap water into a beaker and then add about 1 mL of bromothymol blue to the water in the beaker.

2. Using a clean straw, you would then gently blow into the solution until the color of the solution turns yellow.

3. You would next fill three test tubes 2/3 full with this yellow-colored solution.

4. Then, you would place a 3-inch cutting of Elodea into Tube 1 and another 3-inch cutting of Elodea into Tube 2, making sure that the cuttings were completely immersed in the solution. After this, you would wrap Tube 1 with green film. Tube 3 will be left alone and will not contain a plant cutting.

5. Watch the following video about setting up the photosynthesis lab from time 0:00 until 5:46.

https://www.youtube.com/watch?v=GWUawtweJGM

Ignore the use of a second plant in the video, we only use Elodea in this laboratory activity. In the video, Tubes 1 and 2 contain Elodea plant cuttings and Tube 1 is wrapped in foil instead of green film.

In our photosynthesis lab experiment, we wrap Tube 1 in green film, which only allows green-colored light to reach the Elodea plant cutting. The green film we use ends up having the same effect as the aluminum foil used in the video.

6. In Table 1 in the Lab Worksheet, record the color of the solution before blowing into it in the “before exhaling” column.

7. In Table 1 in the Lab Worksheet, record the color of the solution after blowing into is in the “after exhaling column.

8. Answer question 1 in the Lab Worksheet

9. In the laboratory, you would then place the test tubes in front of a light source such as a fluorescent lamp. You would allow the tubes to be exposed to the light for 1 hour.

10. Record the color of the solution in each test tube in Table 2 of the Lab Worksheet

11. Make a hypothesis about how the color of bromothymol blue solution in each test tube will change and record the color you expect for each tube in Table 2 in the “Expected Color after 1 hour of light exposure” column.

When making a hypothesis, consider why the pH-indicating solution turned color in the first place and what might happen if the substance that caused the color change was removed by a plant performing photosynthesis.

12. Watch the following video showing the results of photosynthesis lab from time 0:00 until 2:41.

https://www.youtube.com/watch?v=SZsQG_rPJwQ

In the video, Vial A corresponds to Tube 1 in our photosynthesis lab experiment. Ignore Vial B from the video. Vial C in the video corresponds to Tube 2 in our photosynthesis lab experiment and Vial D in the video corresponds to Tube 3 (the control).

Note that in our photosynthesis lab experiment, we wrap Tube 2 in green film, which only allows green-colored light to reach the Elodea plant cutting. The green film we use ends up having the same effect as the aluminum foil used in the video.

13. Using the results diagrammed below, fill in Table 2 in the Lab Worksheet

14. Record the color you observe for each test tube in Table 2 in the “Observed color” column.

15. Answer questions 2 – 3 in the Lab Worksheet.

Experiment 2. Absorption spectrum of leaf extract (work in groups)

1. In the laboratory, you would first turn on the spectrophotometer and allow it to warm up for 15 min.

2. You would then insert the blank cuvette (which contains alcohol) in sample holder marked “B” and the cuvette containing leaf extract in sample holder “1”, making sure that the orientation of the cuvettes is correct.

3. Then, you would select a wavelength to measure and calibrate the spectrophotometer by measuring the absorbance of the blank cuvette at this wavelength. You would then see the absorbance reading set to 0.

4. Now, you would measure the absorbance of the cuvette containing the leaf extract and record the absorbance in Table 3 in the position corresponding to the wavelength you selected.

5. You would repeat steps 3 – 4, changing to a different wavelength each time, until all the wavelengths in Table 3 had been measured. Record absorbance readings in Table 3.

6. Watch the following video about using a spectrophotometer from time 0:00 until 4:43.

https://www.youtube.com/watch?v=C-M7EtSuD40

Note that the video uses a tube containing a red liquid, while in our photosynthesis lab, we would use a tube containing leaf extract (which would appear green) as our sample tube and a tube containing alcohol (which would be transparent) as our blank tube.

7. Table 3 has been partially filled in for you in the Lab Worksheet. Complete Table 3 by filling in the color of light that corresponds to the grouped wavelengths.

8. Answer question 4 by making a Line Graph of the data in Table 3.

9. Answer questions 5 and 6 based on your Line Graph

10. Answer question 7 based on the results of both Experiment 1 and Experiment 2.

BIO 101 Lab 08: Photosynthesis Worksheet

Name: __________________________ Section: ______________________

Data Analysis and Synthesis Questions:

Table 1. pH-indicating dye color

1. Why did the solution in the beaker change color after you exhaled?

Table 2. Observing Photosynthesis

2. In this experiment , what is the purpose of the tube without the plant?

3. Explain the color change or lack of color change in the three experimental tubes:

a. Tube 1:

b. Tube 2:

c. Tube 3:.

Table 3. Absorbance of Different Wavelengths of Light

4. Make a Line Graph of the absorbance readings versus the wavelength of light data from Table 3. Be sure to include x-axis and y-axis labels and a chart title.

5. Which wavelength(s) and colors of light are most effectively absorbed by leaf pigments (where are the peaks in your Line Graph)?

6. Which wavelength(s) and colors of light are poorly absorbed (where are the valleys in your Line Graph)?

7. Draw a general conclusion about which color(s) of light are best for plant growth based on your data from both the measurement of absorbance of light in leaf extracts and the observations of CO2 use by Elodea cuttings in different light conditions.

Lab 05: Photosynthesis

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