Distinguish between the concepts of sexual differentiation and sex determination.

Video transcript

Hi everyone, welcome back, Let's look at our next question. It says blank is the process that leads to the formation of the phenotype where blank is the term for the stage of development that leads to either male or female. So this can be a little bit tricky um To distinguish the answer choices were given or possibilities were given in our answer choices are sex determination, sex differentiation and sexual maturation. So let's maybe talk a little bit about each term. Um to understand best how we should match these terms to our question. So we'll start with sex determination. Sex determination. Is that biological mechanism that determines the sexual traits or phenotype? So this is that foundational biological mechanism present in the beginning of development in that zygote inherited from the parents that determines the sexual phenotype. So for instance, in humans and many other species. Um it's the presence of an S. R. Y. Gene on the Y chromosome that Y chromosome was present with its S. R. Y. Gene. The individual be funny. Typically male. If the Y chromosome is absent, the individual beef in a typically female um Regardless of the number of X chromosomes, fruit flies have a little bit of different sex determination system. And fruit flies, it's the number of X chromosomes that determines male or female phenotype. So we see that sort of from the beginning that basic biological determination of sex. Now let's look at sex differentiation. Our next term. So sex differentiation is that pathway toward the development of the sex phenotype. So starting with an undifferentiated zygote which has the genes as part of its sex determination. Sex differentiation is the process or the pathway in embryonic development of actually developing that sexual phenotype. And then finally we have sexual maturation and sexual maturation. It's something that's talking about later on in development. And put away up here. It's the phase of life during which the gonads, internal sex organs and external genitalia grow and mature and secondary sex characteristics develop. So we also know this as puberty. So we're gonna go ahead and rule out sexual maturation. Um We're talking here in our question about formation of phenotype a stage of development. We're not talking about that sexual maturation that's part of puberty. So we're gonna go ahead and eliminate our answer choices with that as our term. So Choice D. Here and choice C. Have sexual maturation in them and now when we look at A. And B. We just have to determine which is the correct matching of sex determination and sex differentiation. So looking back at our uh question again the first one is the process that leads to the formation of phenotype. The second term is the stage of development. Well the second term is a little easier here because it's talking about a stage of development that leads to either male or female. So we know that stage of development is sex differentiation. That's when the zygote differentiates in the formation that genotype. So the second term will be sex differentiation. So that would be choice A. And then we'd say does the first term fit sex determination? The process that leads the formation of phenotype? Yes, that could fit there. So Choice A. Has the correct terms in the correct order. Sex determination is the process that leads to the formation of the phenotype, whereas sex differentiation is the term for the stage of development that leads to either male or female. Um We can see that choice B has the right terms but the wrong order. So that's why that's not correct. So again, our answer here, Choice A. See you in the next video.