Why is there a trade-off between survivorship and fecundity?

Question

Accepted Answer

Hi everyone. Let's look at our next question. It says if a female lizard devotes a high amount of energy to produce an enormous number of offspring, she won't be able to devote the same amount of energy to her immune system growth, nutrient stores, or other survival traits. This is an example of. So we have a situation where we see an increase in the number of offspring at the expense of a decrease in survival traits. So we're seeing the increase in one aspect of fitness um traded off at the expense of a decrease in another aspect of fitness, recalling that fitness in biology means the ability of an organism to survive to reproduce and pass on it's jeans. So again, there's two parts of fitness, not just the ability the organism to survive in a given environment, but also to reproduce. And pass on its genes. So that means you could see a situation like this where just pure survival ability is decreased to allow greater reproductive success since fitness involves both of those aspects. So in this case, you're seeing a trade off between survivorship and fecundity. So when we look at our answer choices, we see that choice B is fitness tradeoffs. And that is what's happening here. We trade off one aspect of fitness. Um the survival of the organism traits that help its survival for another one, the number of offspring allowing a greater opportunity to pass on its genes and for the survival of those genes. So let's look at our other amateur choices and see why they're not the correct answer choice A. Is dispersion. Dispersion is when a population moves away from parents, offspring moving away from parents uh for the sake of accessing additional resources. Or if environmental changes cause a change in the environment and the offspring need to move to more favorable environment. But that's not describing the situation here. So not our answer choice C says population growth is describing a general increase in the amount of the population but not describing that trade off between higher number of offspring and survival traits. So not our answer. And finally, Choice D. Says carrying capacity, carrying capacity is the size of a population that can exist in a given area. So essentially an area a little area of environment, what size population of a specific species can it sustain? Doesn't have the resources for? Um but not describing our lizard situation. So not our answer. So again, when the female lizard can devote a high amount of energy to produce enormous number of offspring, she won't be able to vote the same amount of energy to survival traits. And this is an example of choice B fitness tradeoffs. See you in the next video

Why is there a trade-off between survivorship and fecundity?

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