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Population Dynamics - Coggle Diagram
Population Dynamics
Birth and Death Rates
The population grows and shrinks because of many factors. One of them is birth rate. “Birth rate is the amount of BIRTHS ocurring at a certain time.”
Death rate, on the other hand, is the opposite of birth rate. It is the number of DEATHS occuring in a period of time. It is also possible to represent this data using graphs (Slide 8).
Growth rate is birth rate - death rate. This is the simplified version. Immigration and emmigration (Last slide), are also included. So technically, growth rate= (births+immigration) – (deaths+emigration).
Density dependent factors are triggered by increasing population density, like shortage of food and water. An animal’s chance of survival depends on how many other animals are living in its area.
Density independent factors also reduce the population by the same proportion, but don’t require a certain population size.
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Resource Availability
Resource Availability is a very important factor to determine population size. If there are lots of resources, that can decrease competition, since most individuals and populations can have that resource without competing too much for it.
But if there are too little resources, competition increases, causing the population to decrease, since animals are going to be fighting over those small resources.
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