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Polar Bear Picnic

The Wilder, the Better

Doctor Fish

Tuna in the Tank

Zoos as Arks

Return to the Wild

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The New Zoos: Zoos as Arks

With about 1,000 giant pandas left in the wild, this roly-poly animal is on the verge of extinction. An effective captive breeding program is critical to the animal's survival. But captive breeding of pandas has had limited success, because their mating habits are poorly understood. Scientists working to learn more about panda biology and behavior hope to gain insights that will help the species survive in the wild.

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Activity: Population Paradox




habitat destruction






The growth of one animal's population, such as humans, can have a profound impact on other animals. This is the case with the giant pandas, whose habitat is gradually being destroyed by human encroachment, leaving fewer than 1,000 animals in the wild.

As you plot the world population graph in this activity, consider the effects of human population growth. The survival of endangered species like the panda often depends on the success of programs like the one at the San Diego Zoo, seen in this episode.


Plot a graph to illustrate the impact of human population on endangered species.

  • graph paper
  • ruler
  1. On a sheet of graph paper, plot the horizontal (x) axis and vertical (y) axis for your graph. Each should be 10 cm long. Make a large mark every centimeter and a small mark every half centimeter on each axis.

  2. On the horizontal axis, each centimeter equals 100 years. Start at the year 1000 and label each centimeter that follows until you get to the year 2000.

  3. On the vertical axis, each centimeter equals an increase in population by 1 billion. Label this axis 1 through 10 billion.

  4. Use the data in the World Population Table and place an X at each point represented by a year and population number. Or, consult an almanac or the Population Reference Bureau for specific data about human population statistics.

  5. Connect the dots to see what kind of curve appears. Use the information to estimate the population for the year 2000 and beyond -- 2010, 2020.


  1. What shape is your graph? It should be a classic J-shape, indicative of a population with few limits to its growth. Most animal populations, other than humans, level off after a time. Their growth graph would look more like an S curve. What factors influence the growth of most populations?

  2. The panda has become the symbol for endangered species. What consequences of human population growth have brought the panda population to the brink of extinction and limit its growth now?

  3. At the rate the human population is growing, adding about a billion people every 10 to 12 years, what might happen to the panda and other endangered species?

  4. What do you think a panda population curve would look like?

  5. Data show that close to 99% of all species that have ever existed have become extinct. Why should we protect one species if this is the case?


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