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excess baggage hypothesis

excess baggage hypothesis The proposition that organs for which an organism no longer has any use (e.g. functional eyes in some cave-dwelling fish and excess brain tissue in some vertebrates) will be selected against because the energy cost of maintaining them reduces fitness (i.e. they are ‘excess baggage’). The hypothesis also applies to genetically engineered organisms. The cost they incur by carrying inserted genes may reduce their fitness if they are released into the environment, so reducing the risk that release will prove environmentally harmful.

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