Factors Affecting Population Changes



Density-Dependent Factors (refer to p.125-127)
Density-dependent limiting factors depend on population size and operate best when the population is large and dense.
These factors include:
  • Competition- when populations become crowded, organisms compete with each other for food, water and other essentials.
  • Predation- regulation of a population takes place with a predator-prey relationship.
  • Parasitism- take nourishment from host, which weakens or kills them.
  • Disease- parasites like tapeworms cause diseases.

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How does the relationship between the lynx and the hare affect the population?


Density-Independent Factors
Density-Independent factors affect all populations in similar ways, no matter what the population size is.
Some examples would be climate changes, like stoms, floods, fires, hurricanes and droughts.

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This would be an example of a drought.