An Interactive Introduction to Organismal and Molecular Biology, 2021
An Interactive Introduction to Organismal and Molecular Biology, 2021
An Interactive Introduction to Organismal and Molecular Biology, 2021
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POPULATION GROWTH | 93<br />
Although several populations in nature follow logistic <strong>and</strong><br />
exponential growth patterns, population growth can be much<br />
more complicated. For instance, many insects undergo brief<br />
exponential growth, followed by periods of mass death (or drop<br />
in population).<br />
Learn more about population<br />
growth modeling through this<br />
simulation!<br />
Example<br />
Population growth may not look like either exponential or logistic growth models. For instance,<br />
the horse population on Assateague Isl<strong>and</strong> in Maryl<strong>and</strong> (pictured below) experienced increase <strong>and</strong><br />
stabilization—similar <strong>to</strong> logistic growth—but then underwent a stable decline.<br />
To complicate the interpretation of this graph further, the stabilization <strong>and</strong> decline were due <strong>to</strong><br />
human management of the population. Studies showed that the environment would not sustain<br />
such a large population over time, <strong>and</strong> many of the plant-species’ population growth would drop<br />
dramatically—eventually causing a crash in the horse’s population size. Managers injected female<br />
horses with a vaccine that caused immune cells <strong>to</strong> attack sperm cells.
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