Many frogs and mice are similar in size, yet a frog egg is vastly larger than a mouse egg. Propose a plausible explanation for this difference in the egg size.

Video transcript

Hi everyone. Let's look at our next problem. It says human eggs are 0. millimeter in diameter. While frog and fish, eggs range from one millimeter to millimeter. What could have caused this variation egg size among these organisms. So we see that despite the fact that humans are obviously much larger than frogs and fish, human eggs are much smaller. So when we think about what would cause a variation in size of an egg, well, a key component of the egg. Cytoplasm oOPS is nutritional reserves which consist primarily of the yolk and in animals that are nourished by the mother's body. So embryos, they have little to no yolk as it's not really needed since the nourishment comes primarily from the mother. But in eggs outside the mother's body, You can be as much as 95% of the eggs mass. So when we look at this variation in size, the frog and fish being much larger, we can assume that it's because they have this majority content of yolk to nourish that embryo outside of the mother's body. So when we look at choice A we see that says the nourishment sources. So that is our correct answer. But we'll just look briefly at our other choices. Choice B says the number of spermatozoa that can fertilize the egg. Well, in all these cases it's just one sperm that fertilizes a single egg. So that is not different. It's not our answer choice C says the season of production, but that doesn't determine egg size. So that's not the answer. And finally, Choice d the size of the organism. Well, as we see, the human egg is much smaller, even though human, adult human is much larger than a frog or fish. So that's not what we're looking for either. So again, what causes the variation? Egg size and humans versus frog and fish? And that's choice. A The nourishment sources hope to see you in the next video.