Short Answer/Free Response Questions Ch. 3 and 5

Short Answer/Free Response Questions Ch. 3 and 5

1. Look at the picture and answer the following questions (this picture is also in your textbook ch. 5):

(a) Explain how this human impact on a forest ecosystem might affect the ability of some species to move to more suitable habitats as Earth's climate changes.

(b) Propose and explain using key concepts and terms one alternative plan that could have preserved this forest ecosystem.

(c) Distinguish between the terms microevolution and macroevolution. Explain how the organisms in forest A could evolve into species different from those in forest B.

2. Read the following article, which appears courtesy of The University of Texas Health Science Center at San Antonio, and answer the questions below.

DRUG-RESISTANT E. COLI AND KLEBSIELLA BACTERIA FOUND IN HOSPITAL SAMPLES AND ELSEWHERE IN U.S.

A research team from The University of Texas Health Science Center at San Antonio, examining bacterial isolates obtained in hospital and non-hospital clinical settings between 2000 and 2006, has identified drug-resistant strains of E. coli and Klebsiella bacteria in more than 50 blood, urine and respiratory samples. These resistant strains, which resemble bacteria reported in Latin America, Asia and Europe, were thought to be rare in the U.S.

“This antibiotic resistance problem is likely to become widespread,” said paper co-author Jan Evans Patterson, M.D., professor of medicine, infectious diseases and pathology at the UT Health Science Center. “It affects the way we will treat infections in the future. In the past, we were concerned with antibiotic resistance in the hospital primarily, but in this review many of the strains we detected were from the community. This tells us antibiotic resistance is spreading in the community, as well, and will affect how we choose antibiotics for outpatient infections.”

If the trend continues, it may become difficult to select appropriate antibiotic therapy for urinary tract infections, for example. “The trend over the last decade has been to treat urinary infections empirically, to pick the drug that has worked,” said James Jorgensen, Ph.D., professor of pathology, medicine, microbiology and clinical laboratory sciences at the Health Science Center. “Now it is important for physicians to culture the patient’s urine to be sure they have selected the right antibiotic. The top three drugs that are often prescribed may not be effective with these resistant bacteria.”

(a) Explain how drug-resistant strains of bacteria could evolve in a hospital.

(b) According to the article, what is it that the scientists are now concerned about that they were not concerned about in the past?

(d) Propose two possible solutions to the current problem of drug-resistant bacteria.

3. The population density of large carnivores is always very small compared to the population density of herbivores occupying the same ecosystem. Explain this in relation to the concept of an ecological pyramid.

4. Why do farmers NOT need to apply carbon to grow their crops but often need to add fertilizer containing nitrogen and phosphorus?

5. Could a balanced ecosystem exist with only producers and decomposers and no consumers such as humans and other animals? Explain why or why not?

6. Draw and label the carbon cycle.

Name and describe the two major biological processes involved in the carbon cycle.

What two human activities have disrupted the carbon cycle? Explain! What evidence have scientists gathered to indicate that these two activities have led to global climate change? (include and explain graph of Keeling Curve)

7. Nitrogen is crucial for sustaining life in both terrestrial and aquatic ecosystems.

(a) Draw a fully labeled diagram of the nitrogen cycle. (4 points) (hint) See Figure 3.12 on page 70.

(b) Describe the following steps in the nitrogen cycle:

(i) Nitrogen fixation (1 point)

(ii) Ammonification (1 point)

(iii) Nitrification (1 point)

(iv) Denitrification (1 point)

(d) Describe one way that the nitrogen cycle can be disrupted by human activities. (1 point)

8. Read the following article written for a local newspaper and answer the questions below.

Neighbors Voice Opposition to Proposed Clear-Cut

A heated discussion took place last night at the monthly meeting of the Fremont Zoning Board. Local landowner Julia Taylor has filed a request that her 150-acre woodland area be rezoned from residential to multi-use in order to allow her to remove all of the timber from the site. “This is my land, and I should be able to use it as I see fit,” explained Ms. Taylor. “In due course, all of the trees will return and everything will go back to the same as it is now. The birds and the squirrels will still be there in the future. I have to sell the timber because I need the extra revenue to supplement my retirement as I am on a fixed income. I don’t see what all the fuss is about,” she commented.

A group of owners of adjacent properties see things very differently. Their spokesperson, Ethan Jared, argued against granting a change in the current zoning. “Ms. Taylor has allowed the community to use these woods for many years, and we thank her for that. But I hope that the local children will be able to hike and explore the woods with their children as I have done with mine. Removing the trees in a clear-cut will damage our community in many ways, and it could lead to contamination of the groundwater and streams and affect many animal and plant species. Like the rest of us property owners, Ms. Taylor gets her drinking water from a well, and I do not think she has really looked at all the ramifications should her plan go through. We strongly oppose the rezoning of this land—it has a right to be left untouched.”

After more than two hours of debate between Ms. Taylor and many of the local residents, the chair of the Zoning Board decided to research the points raised by the neighbors and report on his findings at next month’s meeting.

(a) Name and describe the ecosystem value(s) that are being expressed by Ms. Taylor in her proposal to clear-cut the wooded area.

(b) Name and describe the ecosystem value(s) that Mr. Jared is placing on the wooded area.

(c) Provide three realistic suggestions for Ms. Taylor that could provide her with revenue from the property but leave the woods intact.

(d) Identify and discuss the validity of the environmental concerns that were raised by Mr. Jared. (3 points)

9. Scientists are alarmed at the drastic decline of amphibians in the last decade. In particular, frog populations seem to be declining at an alarming rate. The population decline seems to be linked to effects of exposure to harmful factors that occur at different points during the life cycle. Some of the environmental threats are natural while others are generated through human activities. Frogs are also sensitive to pesticides that make their way into our soil, air, and water.

a)Other than pesticide poisoning, identify and describe TWO possible reasons for the frogs’ decline in the ecosystem.

b)Describe two reasons why the frog may be particularly susceptible to pesticide poisoning in the environment.

c)Certain amphibians are considered indicator species for the ecosystem. Give an example of another indicator organism and explain the environmental threat to which it may give warning.

d)Identify TWO characteristics of species who are specialists that can make them more vulnerable to environmental threats.