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Ch. 51 Animal Behavior

Chapter 51, Problem 6

Which of the following is not required for a behavioral trait to evolve by natural selection? a. In each individual, the form of the behavior is determined entirely by genes. b. The behavior varies among individuals. c. An individual's reproductive success depends in part on how the behavior is performed. d. Some component of the behavior is genetically inherited.

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Welcome back. Here's our next question. All of the following are required for the evolution of a behavioral trait by natural selection. Except so let's recall from our content videos that natural selection involves environmental pressures causing certain genetic traits to make an individual more or less likely to be able to survive to reproduce and pass on their genetic trait. So with that in mind let's look at our choices. We are looking for the one that is not required for behavioral trait to evolve by natural selection. So Choice A. Says lack of influence on the behavior by the environment. Well, natural selection by definition acts when the environment causes pressure to favor or disadvantage certain traits. So if the environment is not exerting any pressure um on that specific behavior, it's not giving the behavior a benefit in that environment or a disadvantage, then that is not required for a behavioral trait to evolve by natural selection because we don't have the selection pressure. So choice A. Is not required and therefore must be our correct answer. But let's just look at our other three choices um Which by by that logic are required for the evolution of a behavioral trait just to fully understand this. So when we look at choice B. We C. B. Says variations of behavior among individuals. Well again when we look at natural selection, it's favoring a trait or not. So you want to see differences among individuals of all the individual the same behavior. There's nothing to be selected by natural selection. So variations of behavior are required if you want to see a behavioral trait give an advantage or be discouraged. Choice C. Says reproductive success of animals depends on the expression of the behavior and that is required because evolution requires the change in the genetic trait. So you want to see the behavioral trait giving an advantage to individuals with it, making it more likely for them to reproduce. That's again how natural selection exerts this pressure on the genome. So choice C. Is not our answer because it is required. And Choice D. Says some behavioral components are genetically inherited. And yes, because we're talking about evolution change to the genes as caused by a trait making it more likely to pass on those genes more likely to reproduce. You need to see genetically inherited behavioral traits for behavioral traits to be to evolve by natural selection. So Choice D. Is required and therefore is not our answer. Hope that helped see you in the next video.