HPG - Concerns with Population Growth Lesson

Concerns with Population Growth

Does This Come in a Bigger Size?

During October 2011, the world's population surpassed 7 billion people. It took just 12 years for the population to increase by a billion people. At this rate, many are predicting that there may be well over 9 billion people by 2050.  How does the increase in population affect Earth?

More People More Problems

The human population is now growing by more than 200,000 people a day. The human population may well be close to its carrying capacity. However, we have yet to hit it. As we get more and more people on Earth, the effects are felt economically. Throughout history, populations that have high rates of growth create environmental problems.
A rapidly growing population uses resources at an increased rate & can overwhelm the infrastructure of a community. Infrastructure is the basic facilities of a country or region, such as roads, bridges, sewers, power plants, subways, schools, & hospitals. Symptoms of overwhelming populations include suburban sprawl, polluted rivers, barren land, inadequate housing, & overcrowded schools.

Universally, rapid population growth causes these problems:

	Impacts on Land More people mean fewer places for people to be able to – have shelter and food to be grown for them. Arable land is farmland that can be used to grow crops. Growing populations make trade-offs between competing uses for lands such as agriculture, housing, or natural habitats. For example, Egypt has a population of more than 69 million that depends on farming within the narrow Nile River valley. Most of the country is desert, and less than 4 percent of Egypt's land is arable. The Nile River Valley is also where the jobs are found, and where most Egyptians live. They build housing on what was once farmland, which reduces Egypt's available arable land. Urbanization is an increase in the ratio or density of people living in urban areas rather than in rural areas. People often find work in the cities but move into suburban areas around the cities. This leads to traffic jams, inadequate infrastructure, & reduction of land for farms, ranches, & wildlife habitat. Meanwhile, housing within cities becomes more costly, denser, & in shorter supply.
	Impacts on Water In places that lack infrastructure, the local water supply may be used not only for drinking & washing but for sewage disposal. The water supply then becomes a breeding ground for organisms that can cause diseases. Even in cities that have an infrastructure, the populations are doubling every 15 years, & water systems cannot be expanded fast enough to keep up with this growth.
	Impacts of Obtaining Energy Example Low Fuel Wood Standards of living decline when wood is removed from local forests faster that it can grow back. Fuelwood ensures that people can boil water & cook food. Without fuelwood, people suffer from disease & malnutrition.

With so many more people on the planet than ever before, we must ask whether humans now are exceeding Earth's carrying capacity for our species. In ecology when the number of births equals the number of deaths, the population is at its carrying capacity for that habitat. In a population at its carrying capacity, there are as many organisms of that species as the habitat can support. The carrying capacity depends on biotic and abiotic factors. If these factors improve, the carrying capacity can increase. If the factors become less plentiful, the carrying capacity drops. If resources are being used faster than they are being replenished, then the species has exceeded its carrying capacity. If this occurs, the population will then decrease in size.

Limiting Factors

Every stable population has one or more factors that limit its growth. A limiting factor determines the carrying capacity for a species. A limiting factor can be any biotic or abiotic factor: a nutrient, space, and water availability are examples. The size of a population is tied to its limiting factor. Many anthropologists say that the carrying capacity of humans on the planet without agriculture is about 10 million. This population was reached about 10,000 years ago. Farming allowed us to grow the plants we wanted to eat, and raise animals to have food available year-round. We domesticated animals to have meat when we wanted.

Let's expand and review Human Population Growth

Concerns with Population Growth Challenge Activity

Before You Go, You Need To Know

The following key points are from this explore section of the lesson. You must know the following information before moving to the next lesson. This is just a summary of the key points.

• List three problems that can be caused by rapid population growth
• Differentiate between carrying capacity and limiting factors
• Understand the Earth’s population is growing just not exponentially
• Understand the difference between R- strategist and K-strategist organisms

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