In this Grade 7 Life Science lesson from Chapter 8, students learn how limiting factors, immigration, and emigration affect population growth and stability. They explore the population change formula and examine how abiotic factors and competition between species can prevent a population from growing indefinitely. Students also investigate two reproductive strategies, opportunist and competitor, and how population density influences the pressures a population faces.
Section 1
Limiting Factors Control Population Growth
Both living and nonliving factors prevent populations from growing indefinitely. Density-dependent factors like competition and disease increase in effect as population density rises, while density-independent factors like fires affect all populations equally.
Section 2
Scientists Track Population Changes Through Four Factors
Population change equals births plus immigration minus deaths and emigration. Scientists use this formula to analyze how populations grow or decline as individuals enter and leave specific areas.
Section 3
Organisms Adopt Different Reproductive Strategies
Opportunists reproduce rapidly with many offspring and short lifespans, adapting quickly to environmental changes. Competitors live longer with fewer offspring that develop slowly but have higher survival rates.
Section 4
Population Density Influences Resource Competition
As populations grow denser, individuals compete more intensely for limited resources like food and space. This competition acts as a natural regulator, potentially reducing population size when resources become scarce.
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Section 1
Limiting Factors Control Population Growth
Both living and nonliving factors prevent populations from growing indefinitely. Density-dependent factors like competition and disease increase in effect as population density rises, while density-independent factors like fires affect all populations equally.
Section 2
Scientists Track Population Changes Through Four Factors
Population change equals births plus immigration minus deaths and emigration. Scientists use this formula to analyze how populations grow or decline as individuals enter and leave specific areas.
Section 3
Organisms Adopt Different Reproductive Strategies
Opportunists reproduce rapidly with many offspring and short lifespans, adapting quickly to environmental changes. Competitors live longer with fewer offspring that develop slowly but have higher survival rates.
Section 4
Population Density Influences Resource Competition
As populations grow denser, individuals compete more intensely for limited resources like food and space. This competition acts as a natural regulator, potentially reducing population size when resources become scarce.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter