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← Insects are scared to death of fish

JuJu's Avatar Jump to comment 19 by JuJu

Comment 16 by Greyman

Not entirely. Remember that larvae not stressed by predators are more likely to be eaten.

Being stressed to the point of fleeing or doing something else that doesn't get you killed is quit different from dying right on the spot or not developing at all because of stress. Dying of stress doesn't pass on any more successful genes than getting eaten.

Mutation rates are also increased by stress. Organisms in hazardous environments are thus more likely to produce offspring with an adaptive mutation if they are stressed by the situation.

Ones that die prior to having offspring because they were stressed to death don't have offspring. Is there any evidence that an organism in a stressful environment will have an increased mutation rate? Won't the rate of mutation and variation remain the same? Its the ones that don't stress to the point of death, the ones that have what it takes to avoid that scenario who survive and at least have a chance at having offspring.

Being in an environment where predators are close by will give an organism who just happens to have a genetic make up capable of avoiding death prior to having offspring a better chance at survival. That's just natural selection 101.

Being in an environment where predators are close by causing the death of an organism prior to having offspring will cause something like one of these scenarios:

  1. None of the organism have a variation or mutation that allows them to survive past this fatal stress period, so the ones with that genetic make up die off. And the fatal stress genes will become less and less common.

                                           -or-
    
  2. A few of the organisms are lucky enough to have a variation or mutation that allows them to survive and it gives them a way to avoid the fatal stress period, so they survive and have offspring that also have this genetic trait. And the genetic trait that causes fatal stress will become less and less common among the population.

Either scenario will cause the fatal stress characteristic to become less and less common.

Sun, 30 Oct 2011 00:30:46 UTC | #885322