1. What is a Population?

29 March 2005. How Foxes in the Aleutian Henhouse Doomed Islands' Plant Life. By CHARLES PETIT. NY Times. Foxes may not graze, but a new scientific study describes how their arrival on Aleutian islands destroyed rich grasslands and left only sparse tundra. The authors of the report, which appeared in Science last week, say this transformation shows how an entire ecosystem may go into a tailspin if just one new top carnivore shows up. The inadvertent experiment began in the late 1700's and continued into the early 20th century as fur traders looking to expand their supply released nonnative arctic foxes and, in some cases, red foxes on more than 400 Alaskan islands. Some died out, but many populations survived.... The botanical impoverishment that has resulted is the reverse of what usually happens when a new meat-eater comes along. "Traditionally, the predator eats the grazer; the grazer no longer eats the green stuff; and the habitat gets more green," said Dr. Donald Croll, a professor of biology at the University of California, Santa Cruz, and the lead author of the report. An example of the more usual routine is in Yellowstone National Park, where returning wolves, preying on sapling-browsing elk and confining the wary survivors to areas where they can see wolves coming, have touched off a resurgence of willow, aspen and other vegetation. The contrary effect in the Aleutians, once sorted out, has a simple explanation. The grazers on these islands were grass- and seed-eating Aleutian geese, which are smaller cousins of Canada geese. The foxes drove the geese near extinction, which would have been a boon for grasses except that the foxes also feasted on the eggs and hatchlings of puffins, auklets and other ocean-feeding seabirds they found brooding in vast numbers almost everywhere. Some islands lost almost all birds except for cliff-nesting species. And as ground-nesting birds faded, so did their nutrient-rich excrement, or guano, which had been a natural fertilizer. The research team concluded that islands with no foxes received an average 361.9 grams per square meter yearly. Fox-infested islands get just 5.7 grams per square meter of guano per year....

 

2. Patterns in Populations

Archive of Past Articles for Chapter 2

January 2007. Logarithms and Modelling page has problems in exponential growth as part of the Exercises in Math Readiness [http://math.usask.ca/mrc-cgi bin/emr/first_page.cgi]

January 2007. Exponential growth applet - interactive. See also "logistic growth" http://www.otherwise.com/population/logistic.html

Archive of Past Articles for Chapter 2

3. Population Reproduction, Growth, and Change Over Time

Archive of Past Articles for Chapter 3

8 May 2007. A Lonesome Tortoise, and a Search for a Mate. By JOHN TIERNEY, NY Times. Excerpt: When I met Lonesome George two decades ago, in his pen on the main island of the Gal‡pagos, I had the usual impulse to fix up the world's most famous bachelor.... I didn't find her, of course, so I went back to George's pen to bid a sad farewell to him and his species. Then I penned a long - and quite moving, I thought - contemplation of the ethics of conservation, the destructiveness of man and the meaning of life. Now it seems the obituary was premature. ... Last week, after sampling the genes of a few tortoises on Isabela Island, biologists announced that there is probably at least one Pinta tortoise somewhere among the thousands of tortoises there. Next year the researchers hope to find a female to take back to George's pen.
...George is not what you would call a stud. When I visited him in 1985, he was thought to be a relatively young adult, maybe 50 years old, but he was already a confirmed bachelor. He hadn't shown any interest in two females of a similar species placed in his pen. One had flipped over and drowned in the wading pool. The keepers weren't positive that George had driven this tortoise to her death, but he definitely hadn't been doing any Barry White serenades.
A few years later, in 1993, there was briefly a companion known as "Lonesome George's girlfriend," but she was not a tortoise. She was a 26-year-old graduate student in zoology from Switzerland named Sveva Grigioni. By coating her hands in the genital secretions of female tortoises and gently stroking him, she managed to demonstrate a couple of times (in the course of several months' work) that George was capable of an erection. But whereas her touch could induce other male tortoises to reach orgasm within a few minutes, with George she never managed to collect any sperm. ..."He started to try copulation," Ms. Grigioni said, "but it was like he didn't really know how to." To be fair to George, he's never been observed with a female of his race, Geochelone nigra abingdoni....The tortoise populations in the Gal‡pagos were devastated first by hungry whalers and pirates, and then by museum collectors who were far more energetic than the sailors in scouring the islands for the few remaining animals. Until George was discovered, the last tortoises seen alive on Pinta were the ones captured and killed a century ago by an expedition from the California Academy of Science....

Archive of Past Articles for Chapter 3

4. The History of Human Population Growth

September 2004. India's Population to Surpass China's By 2035. The 2004 World Population Data Sheet, released this month by the Population Reference Bureau, http://www.prb.org/, projects an overall global population increase of 45% to 9.3 billion people by the year 2050. The United States is expected to remain the third most populous country through that year, falling behind India, which will become the most populous country, and China, which will drop to number two. PRB predicts that most of the population growth will occur in the developing countries, despite higher HIV/AIDS infection rates and higher infant mortality rates than in the developed world. The figures assume that HIV/AIDS prevalence in Africa will peak in 10-15 years and then rates will drop on the continent, where they are already decreasing in 14 of 38 countries. The gap between the developed and developing countries' figures is also attributed to aging populations, along with more frequent contraceptive use and lower birth rates in several European countries.

Population Density Maps -- http://sedac.ciesin.columbia.edu/plue/gpw

5. The Environmental Impact of Populations

Archive of Past Articles for Chapter 5

10 April 2007. Millions Face Hunger From Climate Change. By THE ASSOCIATED PRESS Excerpt: MEXICO CITY (AP) -- Rising global temperatures could melt Latin America's glaciers within 15 years, cause food shortages affecting 130 million people across Asia by 2050 and wipe out Africa's wheat crop, according to a U.N. report released Tuesday. The report, written and reviewed by hundreds of scientists, outlined dramatic effects of climate change including rising sea levels, the disappearance of species and intensifying natural disasters. It said 30 percent of the world's coastlines could be lost by 2080. ...Polar ice caps will likely melt, opening a waterway at the North Pole and threatening to make the Panama Canal obsolete, IPCC member Edmundo de Alba said. Warmer waters will spawn bigger and more dangerous hurricanes that will threaten coastlines not traditionally affected by them. Latin America's diverse ecosystems will struggle with intense droughts and flooding and as many as 70 million people in the region will be left without enough water, according to the report. ''What's clear is places suffering from drought are going to become drier, and places with a large amount of precipitation are going to see an increase in precipitation,'' de Alba said. Many Latin American farmers will have to abandon traditional crops such as corn, rice, wheat and sugar as their soil becomes increasingly saline, and ranchers will have to find new ways to feed their livestock, scientists said. ...In Asia, nearly 100 million people will face the risk of floods from seas that are expected to rise between 0.04 inches to 0.12 inches annually, slightly higher than the global average. The report suggests that a 3.6-degree increase in mean air temperature could decrease rain-fed rice yields by 5 percent to 12 percent in China. In Bangladesh, rice production may fall by just under 10 percent and wheat by a third by the year 2050. The drops in yields combined with rising populations could put close to 50 million extra people at risk of hunger by 2020, 132 million by 2050 and 266 million by 2080, the report said. ...On the Net: http://www.ipcc.ch/

7 February 2007. China Says Rich Countries Should Take Lead on Global Warming. By JIM YARDLEY, NY Times. Excerpt: BEIJING, Feb. 6 - China said Tuesday that wealthier countries must take the lead in curbing greenhouse gas emissions and refused to say whether it would agree to any mandatory emissions limits that might hamper its booming economy. Jiang Yu, a spokeswoman for the Foreign Ministry, said ... "It must be pointed out that climate change has been caused by the long-term historic emissions of developed countries and their high per capita emissions," she said, adding that developed countries have responsibilities for global warming "that cannot be shirked." ...China is the world's second largest emitter of the greenhouse gases contributing to climate change, .... Last November, the International Energy Agency in Paris predicted that China would pass the United States in emissions of carbon dioxide in 2009. ...Qin Dahe, chief of the China Meteorological Administration, told reporters ... "President Hu Jintao has said that climate change is not just an environmental issue but also ... ultimately a development issue." ..."As a developing country that's growing rapidly and has a big population, to thoroughly transform the energy structure and use clean energy would need a lot of money," Mr. Qin said, according to Reuters...

The Gazette
http://www.populationconnection.org/education/gazette/
Population Activities http://www.populationconnection.org
Population Reference Bureau http://www.prb.org/
United Nations Population fund http://www.unfpa.org/

Archive of Past Articles for Chapter 5

6. One Child

Archive of Past Articles for Chapter 6

6 April 2007. To Fortify China, Soybean Harvest Grows in Brazil. By ALEXEI BARRIONUEVO, NY Times. Excerpt: RONDONîPOLIS, Brazil - For more than 2,000 years, the Chinese have turned soybeans into tofu, a staple of the country's diet. But as its economy grows, so does China's appetite for pork, poultry and beef, which require higher volumes of soybeans as animal feed. Plagued by scarce water supplies, China is turning to a new trading partner 15,000 miles away - Brazil - to supply more protein-packed beans essential to a richer diet. China's global scramble for natural resources is leading to a transformation of agricultural trading around the world. In China, vanishing cropland and diminishing water supplies are hampering the country's ability to feed itself, and the increasing use of farmland in the United States to produce biofuels is pushing China to seek more of its staples from South America, where land is still cheap and plentiful. ...The Chinese want to connect directly with Brazilian farmers, bypassing the multinational grain merchants. While they have yet to make a major purchase of cropland in Brazil, they are looking to invest in improved facilities and upgrade the antiquated rail system.
China began looking overseas for more soybean supplies in the mid-1990s, when the scope of its land and water problems became clearer. Beijing has also chosen to use more of its arable farmland to grow fruits and vegetables, crops that make better use of China's cheap labor and scarcer water supplies to generate higher returns on the export market....

Archive of Past Articles for Chapter 6

 

Chapters:

1. What is a Population?
2. Patterns in Populations
3. Population Reproduction, Growth, and Change Over Time
4. The History of Human Population Growth
5. The Environmental Impact of Populations
6. One Child
7. Can We Limit Human Population Growth?
8. Choosing a World

7. Can We Limit Human Population Growth?

Archive of Past Articles for Chapter 7

11 May 2006. Scientists Will Gather to Discuss Safety of Abortion Pill. By GARDINER HARRIS NY Times. Worried about a bacterial infection that led to the deaths of at least five women who took the abortion pill RU-486, scientists from the nation's leading public health agencies will gather in Atlanta today for the first meeting in 10 years on the drug's safety. ...Abortion experts have been at a loss to explain why four of the deaths occurred in California. Initially, the F.D.A. investigated whether the pills used in California might have been contaminated, but an agency official said tests had found no evidence of contamination. Another theory concerned the role a dry climate might play in encouraging the growth of Clostridium sordellii, which lives in soil. Some experts believe that pregnant women who take RU-486 with another drug, misoprostol, are more vulnerable to infection. RU-486 by itself ends early pregnancies, but the pill is routinely given along with misoprostol, which causes uterine contractions ...There has been no hint that the F.D.A. is considering further restrictions on the use of the drug. ...A 43-year-old New York mother of two who said that she had had "every kind of abortion," told her abortion provider during a counseling session recently that she would consider only a pill-based procedure. "I do not like doctors and hospitals," said the woman, who did not wish her name to be used for privacy reasons. "Both of my children were born at home without anything. And that's how I want to have my abortion: in home, in my privacy, at my own pace and without somebody's other agenda over me." ...Anne Hawkins, 36, also of New York, said she, too, had had both pill-based and surgical abortions. But taking RU-486, she said, "was the worst experience, the most physically and emotionally painful thing, that I've ever been through." Ms. Hawkins had another abortion in March, and she chose surgery. "It was 10 minutes, max, and then it was over," Ms. Hawkins said of the surgical procedure. "The pill for me was the experience of having a baby. Contractions for 10 hours, sweating, screaming, being by myself. It was emotionally scarring and physically horrible."

Archive of Past Articles for Chapter 7

Chapters:

1. What is a Population?
2. Patterns in Populations
3. Population Reproduction, Growth, and Change Over Time
4. The History of Human Population Growth
5. The Environmental Impact of Populations
6. One Child
7. Can We Limit Human Population Growth?
8. Choosing a World

The Gazette
http://www.populationconnection.org/education/gazette/

Population Activities http://www.populationconnection.org

Population Reference Bureau http://www.prb.org/

United Nations Population fund http://www.unfpa.org/

Chapters:

1. What is a Population?
2. Patterns in Populations
3. Population Reproduction, Growth, and Change Over Time
4. The History of Human Population Growth
5. The Environmental Impact of Populations
6. One Child
7. Can We Limit Human Population Growth?
8. Choosing a World