The best definition of evolutionary fitness is                  . a. physical health; b. the ability to attract members of the opposite sex; c. the ability to adapt to the environment; d. survival and reproduction relative to other members of the population e. overall strength

Video transcript

Hi everyone here's our next question. What's the best indicator of evolutionary fitness among organisms? Well let's recall that evolutionary fitness is how well an organism can reproduce in its specific environment. So with that in mind that definition of evolutionary fitness, Let's look at our answer choices. So Choice A. Says reproductive success. Well again we're looking for what is an indicator revolutionary fitness and evolutionary fitness is how well an organism can reproduce. Then we'll want to look at how successful was it reproducing how many offspring did it have? So with that in mind, Choice A is our answer reproductive reproductive success. But to be thorough let's look at our other choices. Choice B says desirable phenotype sis well desirable doesn't really have. Um So much meaning in evolution by natural selection, desirable more refers to artificial selection like breeding because it implies traits looking for traits that are desirable to the person doing the selecting. Um So I'm breeding a breed of dogs to have acute ear shape or something. So Choice B would not be what we talk about in terms of evolution, choice E says mating preference. So many preference can be part of the picture. Mating preference would be um You know, a female choosing a male with brightly colored feathers so the bright colored feathers aren't necessarily beneficial adaptation. But her choice of those males will result in passing on those genes but that's not an indicator of how well it reproduces that just as part of the picture. So Choice C. Is sort of related to this issue but not an indicator of evolutionary fitness. And finally, Choice D. Population diversity. Um Population diversity just means you have a lot of um many different species in an environment and that's not really that's an indicator of evolutionary fitness that just tells us lots of different species are there? Um So we want to look at a given organism how well it can reproduce. So population diversity um not what we're looking for. So again, choice a reproductive success is the best indicator of evolutionary fitness. Thanks for watching.