2.3 AGRICULTURE & HUMANS


Video Homework 1

Advances in Agriculture and Population

Every major advance in agriculture has allowed global population to increase. Early farmers could settle down to a steady food supply. Irrigation, the ability to clear large areas of land for farming, and the development of farm machines allowed people to grow MORE food and MOVE it to where it was needed.

Hunters and Gatherers

In a hunter-gatherer society, people relied on the resources they could find where they lived. [2]

Farming

About 10,000 years ago, we developed the ability to grow our own food. Farming increased the yield of food plants and allowed people to have food available year round. Animals were domesticated to provide meat. With agriculture, people could settle down, so that they no longer needed to carry all their possessions (Figure below). They could develop better farming practices and store food for when it was difficult to grow. Agriculture allowed people to settle in towns and cities.

(a) Like early farmers, subsistence farmers today grow only enough food for their families, with perhaps a bit extra to sell, barter, or trade. (b) More advanced farming practices allowed a single farmer to grow food for many more people. [3]

When advanced farming practices allowed farmers to grow more food than they needed for their families (Figure below), some people were then able to do other types of work, such as crafts or shop keeping.

Farming has increasingly depended on machines. Such advanced farming practices allow one farmer to feed many more people than in the past. [4]

The Green Revolution

The Green Revolution has allowed the addition of billions of people to the population in the past few decades. The Green Revolution has improved agricultural productivity by:

  • Improving crops by selecting for traits that promote productivity
  • Increasing the use of artificial fertilizers and chemical pesticides.
  • Agricultural machinery: plowing, tilling, fertilizing, picking, and transporting are all done by machines. About 17% of the energy used each year in the United States is for agriculture.
  • Increasing access to water. Many farming regions depend on groundwater, which is not a renewable resource. Some regions will eventually run out of this water source. Currently about 70% of the world’s fresh water is used for agriculture.

Rows of a single crop and heavy machinery are normal sights for modern day farms. [6]

The Green Revolution has increased the productivity of farms immensely. A century ago, a single farmer produced enough food for 2.5 people, but now a farmer can feed more than 130 people. The Green Revolution is credited for feeding 1 billion people that would not otherwise have been able to live.

 

VIDEO HOMEWORK 2

 

Practice

Use this resource to answer the questions that follow.

http://www.youtube.com/watch?v=r1ywppAJ1xs

1. Who was Thomas Malthus?

2. What did Malthus think would happen as population increased?

3. What did Malthus think would limit population?

4. What is the Malthusian limit?

5. What is happening to population growth in some developed countries today?

6. Malthus didn’t account for what in his theory?

7. What country is close to the Malthusian limit today?

Review

1. Link major advances in agriculture and industry with changes in the human population.

2. What is carrying capacity? Has the human population exceeded Earth’s carrying capacity for humans? If so, how could this have happened?

3. What is the Green Revolution? How has it affected human population?

4. What do you think of Thomas Malthus’ prediction? Have we proven Malthus wrong or have we just not gotten to that point yet?

Image Attributions

  1. ^ License: CC BY-NC 3.0
  2. ^ Credit: Image copyright Pichugin Dmitry, 2010; License: CC BY-NC 3.0
  3. ^ Credit: (a) Amcaja; (b) Ralf Roletschek; License: CC BY-NC 3.0
  4. ^ Credit: Courtesy of the US Department of Agriculture; License: CC BY-NC 3.0
  5. ^ Credit: Herman Heyenbrock; License: CC BY-NC 3.0
  6. ^ Credit: NightThree; License: CC BY-NC 3.0
  7. ^ Credit: Image copyright Daniel W, 2010; License: CC BY-NC 3.0

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