The Short Form

Before 1970, United States census data was collected by field workers. They went door to door to count the number of people living in each household. Since then, the census has been done mostly by mail. Census data are important in deciding how to distribute government services and funding.

The 2000 Snapshot

One of the findings of the 2000 Census is that the U.S. population is becoming more equally spread out across age groups. Census officials estimate that by 2020 the population of children, middle-aged people, and senior citizens will be about equal. It's predicted also that there will be more people who are over 100 years old than ever before. Federal, state, and local governments will be using the results of the 2000 Census for years to come as they plan our future.

Census Develop a school census. What questions will you ask? (Don't ask questions that are too personal.) Who will ask them? How will you make sure you counted everyone? Using the results, can you make any predictions about your school's future or its current students?


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Ecology is the study of interactions that take place in the biosphere.

Living Earth

Ecology is the study of interactions that take place in the biosphere.

A population is made up of all organisms of one species living in an area at the same time.

A community is made up of all the populations living in one ecosystem.

Living and nonliving factors affect an organism's ability to survive in its habitat.


1. Population size can be estimated by counting a sample of a total population.

2. Competition for limiting factors can restrict the size of a population.

Population growth is affected by birthrate, death rate, and the movement of individuals into or out of a community.

Exponential population growth can occur in environments that provide a species with plenty of food, shelter, and other resources.

Interactions Within Communities

1. All life requires energy.

2. Most producers use light to make food in the form of energy-rich molecules. Consumers obtain energy by eating other organisms.

3. Mutualism, commensalism, and parasitism are the three kinds of symbiosis.

4. Every species has its own niche, which includes adaptations for survival.

Copy and complete the following concept map on communities.

Copy and complete the following concept map on communities.

Nursing Concept Map For Cancer


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