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Organisms and Populations — BIOLOGY STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceBIOLOGYOrganisms and Populations4 Marks
Question
Explain Predation as population interaction with different example.
✓

Answer

→ In a broad ecological context, all carnivores, herbivores etc. are predators. About 25% insects are phytophagous.
→ If a predator overexploits its prey, then the prey might become extinct. It results in the extinction of predator. Therefore, predators in nature are 'prudent'.
Importance of predators :
→ Predators control prey populations.
→ When certain exotic species are introduced into a geographical area, they spread fast due to the absence of its natural predators.
E.g. Prickly pear cactus introduced into Australia (1920's) caused havoc by spreading. Later, it was controlled by introducing a cactus-feeding predator moth.
→ Predators are used in Biological control methods.
→ Predators maintain species diversity in a community by reducing competition among prey species.
E.g. the predator starfish Pisaster in the rocky intertidal communities of American Pacific Coast. In an experiment, all these starfishes were removed from an enclosed intertidal area. It caused extinction of over 10 invertebrate species within a year, due to interspecific competition.

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