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Population Size and Ecosystems

Population growth and its measurement

  • 3 things to know
  • Component 1

Overview

Four processes that change the size of a population, population's size at the end of the year and birth rate.

What you need to know

Answer each one before you reveal it.

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Key term

What is a population?

Process

Name the four processes that change the size of a population.

Process

Write the relationship between births, deaths, immigration, emigration and population change.

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    What is a population?

    Model answer

    All the individuals of one species living in the same place at the same time and able to interbreed.

  2. 2

    Name the four processes that change the size of a population.

    Model answer

    Births, deaths, immigration and emigration.

  3. 3

    Write the relationship between those four processes and population change.

    Model answer

    Population change equals births plus immigration, minus deaths and emigration.

  4. 4

    What is immigration?

    Model answer

    The movement of individuals into a population from elsewhere.

  5. 5

    What is emigration?

    Model answer

    The movement of individuals out of a population to elsewhere.

  6. 6

    A population of 5,000 has 400 births, 250 deaths, 90 immigrants and 40 emigrants in a year. What is the change?

    Model answer

    400 plus 90 is 490 added, and 250 plus 40 is 290 lost, so the population rises by 200.

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