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changes in Communities.
- Changes that can make a population
- Now that we have learned about the factors that increase population size, let's investigate the
factors that have the opposite influence. The first factor that results in a decrease in the population
size is mortality. Mortality is the number of individual deaths in a population over a period of time.
In terms of the human population, mortality is often described as the death rate, which is the
number of individuals that die per 1,000 individuals per year. Death rates are often used to describe
how many individuals die in specific age groups. For example, the death rate of infants is often an
important statistic to investigate when looking at changes in the population. Similarly to birth rates,
the death rate is also often described as a percentage of the population. In 2010, the death rate for
infants in the United States was 0.6%, while in Ethiopia the infant death rate was 7.1%. The second
factor that can decrease the size of a population is emigration. Emigration is the migration
- Take a minute and think about all of the different people you interact with in a given day. For most
people, this would include family, friends, co-workers, and strangers. A population is often described
as a group of individuals of the same species that inhabit the same area. Therefore, all of the people
you encounter each day are part of your population. Other examples of populations include the
dandelion plants growing in a field or the cockroaches that inhabit a single house. On a larger scale,
you can think of all humans on Earth as the human population. As of 2011, the human population
exceeded seven billion people! Although the human population has been around this size for most of
us for our entire lives, the population has not always been so large. Around 10,000 years ago, before
the invention of agriculture, it is estimated that the human population was only a few million people
worldwide. After the invention of agriculture, the human population began to grow slowly until t
- There are two factors that result in an increase in the size of a population. First, there is natality,
which is the number of individuals that are added to a population over a period of time due to
reproduction. This term is often used to describe reproductive rates over a variety of time periods.
The term most commonly used when describing natality in the human population is birth rate. Birth
rate is the number of individuals born per 1,000 individuals per year. An example of birth rate would
be if a population of 5,000 people resulted in the birth of 50 children in a year, which would yield a
birth rate of ten individuals per 1,000 per year. Birth rate is often reported as a percentage of the
population. In 2010, the birth rate in the United States was 1.38%, which is considerably lower than
the birth rate in many developing countries. For example, in 2010, the birth rate in Ethiopia was
4.34%. Birth rates can vary a great deal by region and can have drastic effects on the overall
- Now that we have learned about the factors that increase population size, let's investigate the
factors that have the opposite influence. The first factor that results in a decrease in the population
size is mortality. Mortality is the number of individual deaths in a population over a period of time.
In terms of the human population, mortality is often described as the death rate, which is the
number of individuals that die per 1,000 individuals per year. Death rates are often used to describe
how many individuals die in specific age groups. For example, the death rate of infants is often an
important statistic to investigate when looking at changes in the population. Similarly to birth rates,
the death rate is also often described as a percentage of the population. In 2010, the death rate for
infants in the United States was 0.6%, while in Ethiopia the infant death rate was 7.1%. The second
factor that can decrease the size of a population is emigration. Emigration is the migration
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