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Page added on December 20, 2013

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Overcoming Density-Dependent Regulation

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Humans have modified their environment to prevent disease and provide shelter and food, overcoming density-dependent population limits.

  1. fig. 1
    Measles cases reported in the United States, 1944-2007

    The number measles cases, reported as thousands of cases per year, shows a decline after the introduction of the vaccine. The inset shows data for 1983-2007 representing reported cases until 1993, after a booster vaccine was added to the recommended vaccination schedule.

    Key Points

    • Humans’ ability to alter their environment is an underlying reason for human population growth, enabling people to overcome density-dependent limits on growth, in contrast with all other organisms.
    • Abilities, such as construction of shelter, food cultivation, and communication to pass on technology, have helped humans overcome factors that would have otherwise limited their population growth.
    • Originating from Africa, human migration to nearly every inhabitable area of the globe has enabled colonization of areas where people were previously absent.
    • Advances in medicine, notably vaccines and antibiotics, as well as improvements in nutrition and vector control, have significantly curbed mortality from disease.

    Terms

    • density-dependent
      processes that occur when population growth rates are regulated by the size of a population in a given amount of resources such as food or habitat area
    • infectious disease
      illness caused by introduction of a pathogen or parasite into the body via contact with a transmitting agent such as vector organism or an infected person
    • vaccine
      a substance given to stimulate the body’s production of antibodies and provide immunity against a disease, prepared from the agent that causes the disease, or a synthetic substitute

     

Overcoming density-dependent regulation

Humans are uniquely able to consciously alter their environment to increase its carrying capacity. This capability is an underlying reason for human population growth as humans are able to overcome density-dependent limits on population growth, in contrast with all other organisms.

Human intelligence, society, and communication have enabled this capacity. For instance, people can construct shelters to protect them from the elements; food supply has increased because of agriculture and domestication of animals; and humans use language to pass on technology to new generations, allowing continual improvement upon previous accomplishments. Migration has also contributed to human population growth. Originating from Africa, humans have migrated to nearly every inhabitable area on the planet. Colonization of new areas has led to the exploitation of environmental regions and indigenous peoples throughout history.

Public health, sanitation, and the use of antibiotics and vaccines have lessened the impact of infectious disease on human populations. In the fourteenth century, the bubonic plague killed as many as 100 million people: between 30 to 60 percent of Europe’s population. Today, however, the plague and other infectious diseases have much less of an impact. Through vaccination programs, better nutrition, and vector control, international agencies have significantly reduced the global infectious disease burden. For example, reported cases of measles in the United States dropped from around 700,000 a year in the 1950s to practically zero by the late 1990s (Figure 1). Globally, measles fell 60 percent from an estimated 873,000 deaths in 1999 to 164,000 in 2008. This advance is attributed entirely to a comprehensive vaccination program.

Developing countries have also made advances in curbing mortality from infectious disease. For example, deaths from infectious and parasitic diseases in Brazil fell from second place as the most important causes of death in 1977 to fifth place in 1984. The improvement is attributed in part to increased access to essential goods and services, reflecting the country’s rising prosperity. Through changes in economic status, as in Brazil, as well as global disease control efforts, human population growth today is less limited by infectious disease than has been the case historically.

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2 Comments on "Overcoming Density-Dependent Regulation"

  1. J-Gav on Fri, 20th Dec 2013 6:33 pm 

    ” … enabling people to overcome density-dependent limits on growth.”

    Euhhh … Yeah, right! Like we can live 10 of us to a square meter and get along just peachy! Sheese!

  2. Visa Express on Mon, 21st Nov 2022 10:16 pm 

    This informative article has captured my attention. So many things have been mentioned here that I had never considered before. You’ve shown me that there’s more than one way to look at these issues. I’m not even sure how I got here, but I thought this publication was fantastic. I appreciate the time and effort you put into it. It is clear. Thank you once again.

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