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24 Dec 2018

In the early years of the conservation movement (1970s), efforts were aimed mainly at the salvation of individual speciesâthat is, saving them from extinction. Today, conservation biology is aimed more at the biodiversity of the entire community and the ecosystem. Explain in detail why there has been this shift in focus. Give a specific example.

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Nelly StrackeLv2

26 Dec 2018

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Related questions

What is a method that some ecologists have proposed to protectspecies from extinction in the face of global climate change?

natural attenuation
assisted migration
bioremediation
mitigation
adaptive management

Why is it usually not possible to restore a community to itspre-altered state?

It is not always possible to determine the kinds of speciesthat populated a community.
Invasive species compromise restoration.
Climate change complicates restoration.
Evolutionary trajectories cannot be predicted.
All answers are correct.

How is ecological restoration different from restorationecology?

It considers cultural and societal concerns.
It does not rely on ecological principles.
It cannot be predicted.
It does not involve manipulation of the environment.
All answers are correct.

What is the goal of assisted migration?

to help species respond to climate change
to help species learn new seasonal migration routes
to help migrating species avoid human-made structures
to help native species tolerate restoration efforts
All answers are correct.

Which of the following might serve to enhance habitat in arestoration project?

a dead log in a stream
a concrete water control structure in an estuary
removal of a dam
an artificial nesting box
All answers are correct.

Biologists want to restore a region that experienced stripmining. How will bacteria assist in the restoration?

They will restore the biotic parts of a community.
They will enhance adaptive management.
They will remove harmful metals.
They will improve revegetation.
They will remove the source of the disturbance.

A barge has leaked a small amount of oil in the middle of LakeMichigan. What might be the best solution to clean it up?

Add molasses to stimulate bacterial action.
Leave it alone.
Introduce engineered bacteria.
Add microorganisms not normally found in the lake.
Launch a comprehensive restoration effort.

Before deciding on an appropriate restoration strategy for aparticular degraded ecosystem, which information would be LEASTimportant to have?

the goals of the restoration, in terms of biodiversity andecosystem functioning
the degree to which the ecosystem has been degraded whencompared to a reference ecosystem
the types of species that were present before thedegradation
the social, political and economic constraints on therestoration
None of the answers are correct.

A biologist works to restore habitat during a restorationproject. Which of the following might serve to enhance thehabitat?

a dead log in a stream
a concrete water control structure in an estuary
removal of a dam
an artificial nesting box
All answers are correct.
10.
Restoration ecologists want to restore a landscape to itsoriginal state before humans arrived and altered it, but they donot know what species of plants lived there historically. What isthe best alternative?
Import plants from other ecosystems at the same latitude.
Bioremediate the soil.
Use plants growing nearby.
Use assisted migration.
Let nature take its course.

11.

Biologists begin collecting native seeds in a seed bank in aregion that experienced considerable alteration. Describe thebenefits of taking this action for the future.

It is important to collect samples of native seeds for culturalpurposes.
Biologists can use the seeds to restore other regions atsimilar latitudes.
If the region is heavily altered, it may take time and multiplesteps to restore the region. Collecting the seeds while they areavailable ensures that the biologists can use them later in therestoration process.
The see bank will promote the assisted migration of plants fromhabitats made unsuitable by climate change.
All answers are correct.

12.

Although disturbance is often thought of as a detriment tonatural ecosystem functioning, one type of disturbance, fire, isoften used to restore ecological communities. In what way(s) canfire restore ecological communities?

Fire is an effective way to "clean the slate" of the ecosystemby burning plants and sterilizing the soil so that appropriatemitigation and bioremediation plans can be implemented.
In ecosystems where fire is a natural periodic event, fire cankill many non-native plant species while leaving native speciesless influenced.
Fire can suppress the growth of competitive dominant plants,such as shrubs and trees, increasing the diversity of certainecosystems.
All answers are correct.
None of the answers are correct.

bronzetermite465

While the concepts of screening and surveillance are intertwined there are subtle distinctions between the two ideas. The main goals are data collection to measure magnitude, changes, and trends in populations. The objective is to create interventions in defined populations. On the contrary, testing to identify individuals with infection or disease is the main goal of screening. The area of breast cancer screening and breast cancer surveillance has been a point of contention. Please read the following article and weigh in on which side seems most convincing:

There is a heated debate in this country about the risks and benefits associated with screening mammography. Proponents on both sides of the debate feel equally as strongly for or against annual breast cancer screening. Despite oneâs opinions regarding the utility of screening mammography, it is difficult to deny that the rates of false-positive exams, the rates of overdiagnosis, and the cost of annual screening are too high. We can do better. It is time to stop devoting energy to arguing about data from studies performed decades ago and start working toward gathering new evidence. In late 2015, we will initiate the WISDOM study to investigate the safety and effectiveness of a personalized breast cancer screening model. This model will use a comprehensive risk assessment process to determine individualized screening regimens for women in the interventional arm. The data collected in this study will better inform the screening debate and will allow us to shed more light and less heat on the issue.

There is a great debate in this country about the risks and benefits of screening mammography. On one side of the debate are those in favor of the one-size-fits-all model of performing annual mammograms starting at the age of 40 for women who are not known to be at greatly elevated risk of developing breast cancer. The radiology community argues that this model reduces the rates of interval cancers, aids early detection, and should not be changed. On the other side of the debate are those who support the United States Preventive Services Task Force (USPSTF) recommendations to screen women biennially starting at age 50, and to screen women in their 40s based on personal preferences regarding the potential benefits and harms of screening.¹ Specialists on this side of the debate believe that annual screening results in unacceptably high rates of false-positive recalls, overdiagnosis, and overtreatment.

Recently, the USPSTF published a draft update to the 2009 breast cancer screening recommendations, and the debate has once again intensified. The solution to this problem is not to continue the debate with repetitious reviews of studies that were performed more than 30 years ago, but to focus ahead on how to make breast cancer screening safer and more effective. The time has come to put the debate to rest by conducting a modern-era screening trial.

Before focusing on the future, let us first take a moment to review the current state of breast cancer screening in the United States. The majority of providers in this country continue to recommend annual screening starting at age 40.² Proponents of annual screening mammography cite a resulting relative reduction in breast cancer mortality of 21%, which is based on data from randomized screening trials performed in the 1970s and 1980s.³ However, this estimated benefit comes with significant drawbacks. After 10 years of annual screening, over one-half of women screened will receive a false-positive recall, and 7% to 9% will undergo a benign biopsy.^4,5 False-positive recalls and benign biopsies can cause long-lasting psychological distress that can negatively impact a womanâs willingness to undergo screening for breast cancer in the future. Additionally, false-positive recalls and overdiagnosis cost the United States an estimated $4 billion per year,⁶ and screening in aggregate is estimated to cost between $8 and 10 billion per year.⁷ This estimate is based on a screening mammogram costing between $135 and $195. If the cost of mammography increases, the overall cost of breast cancer screening increases proportionally. As a country and as healthcare professionals, we can and should do better.

Breast cancer screening should harness the advances that have been made in breast cancer risk assessment and our understanding of breast cancer tumor biology. Screening should be more effective at finding relevant and consequential cancers, and should result in fewer benign biopsies. Screening should also be better integrated with prevention. Lastly, screening should be more cost-effective. A personalized screening model could potentially achieve all of these goals.

The aim of a personalized screening model would be to focus resources on those women who are most likely to benefit. The foundation of the model would be a comprehensive risk assessment that would take into consideration a womanâs classical risk factors for breast cancer, such as her personal and family history of breast disease. This comprehensive risk assessment would also include an evaluation of breast density and germline genetic testing. These risk factors would then be placed into a breast cancer risk model that would estimate the womanâs 5-year risk of developing breast cancer, and personalized screening recommendations would be made according to this risk. Women at high risk of developing breast cancer would be screened more frequently, and women at low risk would be screened less frequently. This risk estimation could also be used to make recommendations regarding chemoprevention, thereby integrating screening and prevention, which is the real key to reducing mortality from breast cancer.

This model has the potential to optimize the benefits of mammography in the context of modern systemic therapy while minimizing harms. Using a similar risk model in 3 independent study populations, it has been shown that 50% of cancers occur in women with the top 20% predicted risk.⁸ This model is also practical because these risk factors are easy to assess, and it is estimated to be more cost-effective than annual screening, despite the use of genetic testing, which has decreased in cost significantly since the Supreme Court ruling in June 2013 that stated that the human genome could not be patented.

Personalized screening may be the way forward, but this can only be determined in the setting of a randomized controlled trial. In the fall of 2015, a randomized controlled trial comparing personalized breast cancer screening with annual screening will be initiated within the Athena Breast Health Network that spans the University of California and the Sanford Health system in the Midwest. This study will be called the WISDOM study (Women Informed to Screen Depending on Measures of Risk). We have received a large grant from the Patient-Centered Outcomes Research Institute to perform this trial, and are also working with payers and self-insured employers, such as Blue Shield of California and UC Health, to create a Coverage with Evidence Development policy that will cover the medical costs of the trial. Using surrogate endpoints and long-term follow-up, we aim to determine whether personalized screening is as effective, less morbid, more preferred by women, and enables prevention more as compared with annual screening. Our hope is that this trial will provide us with the information we need in order to determine the safest and most effective way to screen women for breast cancer. Then, and only then, will we be able to put âThe Great Mammography Debateâ to rest.

As we move toward a more biology-based approach to the treatment of diseases, our approach to screening for and preventing those diseases should follow suit. The opportunity before us is to learn who is at risk for which type of breast cancer, and to optimize our screening and prevention strategies for each individual according to her personal risk. Over the last 20 years, many advances have been made in our understanding of the risk factors that contribute to a womanâs risk of developing breast cancer. The time has come for us to harness this knowledge and apply it in an evidence-generating fashion to shed more light and less heat on the screening controversy.

Do you believe that US Preventive Services Task Force (USPSTF) recommendations should be followed or do you believe screening should start at age 40? Why or why not?

Case Study

Skolnikland is in Eastern Africa, with a population of 30 million people. The country has a plains region, a hill region, and a region with high mountains. It has a number of ecosystems. The plains are dry for much of the year, there is some rainforest, and the rest of the country includes both hills and mountains. There are two seasons of heavy rainfall.

The citizens come from several ethnic groups that tend to live in their own regions and speak different languages. The ethnic groups largely follow one of three different religions. The large cities are mixed ethnically. One ethnic group is economically and socially very dominant. The people from this group live in the capital and most of the large cities. The national language is the language of this dominant ethnic group.

According to World Bank criteria, Skolnikland is among the poorest countries in the world. The economy has been growing at about 4% per year on average over the last decade, but the economy had very slow economic growth in the decades prior to that. The richest 10% of the population controls 80% of the national income.

About 80% of the people live in rural areas and 20% in urban areas. The number of people living in urban areas has been growing recently at an increasing pace. Most people earn their livelihood in agriculture but there is an increasing garment manufacturing industry in the two largest cities. There are also a number of mining industries. In addition, other export industries are beginning to grow, mostly focused on the export of commodities to China.

The total fertility rate is about 4.5 but it has been declining slowly over the last two decades, from over 6. There is an almost equal number of men and women in the population. Infant mortality is about 90 per 1,000 live births. Maternal mortality is about 500 per 100,000 live births. Thirty-five percent of the children are underweight for age.

The adult literacy rate is about 40%. The educational enrollment rate, especially for girls at the primary and secondary levels, has been growing slowly, but steadily. Most recently, this rate has been growing at an increasing pace and about 75% of the girls now attend school regularly, although many of them are of very low quality.

Only about 50% of citizens have access to safe water. Only about 30% have access to sanitary disposal of human waste.

HIV prevalence is 7% of the adult population. The number of new HIV cases annually has begun to plateau. About half of the people eligible for treatment for HIV are on treatment. Malaria is rampant in the plains.

Investments in the road system have been growing at a solid pace in the last decade and the use of private automobiles has begun recently to increase more rapidly.

Skolnikland has a pluralistic health system that is made up of public and private institutions, publicly financed providers, licensed private providers, unlicensed medical practitioners, and traditional healers. There is no health insurance, except for some free services for the poor in the few publicly financed hospitals, which the better off people do not attend. The health system is not very effective or efficient and is generally of low quality. The HIV, TB, and malaria programs are not effective or efficient and they are just beginning to adopt paradigms for services that follow global best practices.

QUESTION 11

If you were interested in investing in maternal and child health using a results-based financing scheme, which program is the most appropriate?

A. Invest in training more skilled birth attendants in a village.

B. A plan to give the local clinic in the village a grant after the clinic demonstrates that its efforts have led after two years to lower under-5 child mortality.

C.Provide all pregnant women in the village with a full course of antenatal vitamins.

QUESTION 12

In Skolnikland today, approximately what proportion of the burden of disease, measured in DALYs, is likely to be Group I-related?

A. 45%

B. 35%

C. 60%

QUESTION 13

In Skolnikland, life expectancy fell in the 1990s, which can be attributed to:

A. Malaria

B. HIV

C. Pneumonia

QUESTION 14

In Skolnikland, the cost for treating severe diarrhea in young children is $18 for community-based care and $20 for clinic-based care. The cure rate for community-based care is 60%. The cure rate for clinic-based care is 90%. Which approach is the most cost-effective?

A. Community-based care

B. Clinic-based care

C. They are equally cost-effective

QUESTION 15

In Skolnikland, what are likely to be three of the five leading causes of death of under-5 children, besides perinatal causes?

A. TB, diarrhea, pneumonia

B. Malaria, diarrhea, measles

C. Diarrhea, malaria, pneumonia