Population Dynamics and Human Impact

Population Dynamics and Human Impact

Module J | Ecology

Lesson Essential Question

How do resources influence population growth and ecosystem stability?

​Human Impact: Populations

​As the human population grows, resources become scarce (food, water, and territory).

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​The change in the population's size per unit of time is known as the population growth rate. It depends on how many organisms are entering and exiting the population.

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​Human Impact: Populations

​Increasing populations (Congo) = more births than deaths​

​Decreasing (Germany) = more deaths than births

​Human Impact: Populations

Population can be exponential ("J Curve")

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​Population increases faster as time progresses.

​Human Impact: Populations

Population can be logistic ("S Curve")

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​Population is limited in resources and starts to decrease in size.

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​Maximum number of organisms in a population that the environment can support = carrying capacity

​Human Impact: Populations

​Resources such as food, water,and territory will limit the population size.

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​Some resources are density-dependent (depends on the number of organisms in the population). For example, food, water, disease, etc

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​Other resources are density-independent (does not depend on the number of organisms) For example, weather disasters, temperature, etc

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​Predator-prey relationships also maintain the population.

Human Impact: Environment​

​Human Impact: Environment

​Human activities can impact our natural environments, for good or for bad.

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​For example, humans burning fossil fuels creates an increase of carbon dioxide within the atmosphere. This increase of carbon dioxide leads to global climate change ("global warming").

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​The use of fossil fuels (oil, coal, and natural gas) helps lead to the greenhouse effect. Methane also contributes to the greenhouse effect.

​Human Impact: Environment

​Human Impact: Environment

​Humans also lead to an increase of waste production and the consumption of resources. ​Humans also lead to habitat destruction which reduces biodiversity.

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​Habitat destruction can be caused by:
deforestation (increases runoff and soil erosion),
increase of pesticide and fertilizers (creates algal blooms),
acid rain (release of sulfates),
farming practices,
release of toxins in the environment,
use of CFCs (destroying of ozone layer), and
introduction of invasive species (upsets the ecosystem).

​Human Impact: Environment

​Humans must take action to maintain stability within our ecosystems.

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​These actions include "Reduce, Reuse, and Recycle" and using better farming/agriculture practices.

End of Lesson