 And we have some terms that we need to define. The first thing we need to define is the word phenotype. A phenotype is a physical characteristic. This says characteristic, a physical characteristic. Now look at each of these. I've got seed shape, I've got S, S, I've got a chromosome, I've got smooth versus wrinkled, smooth versus wrinkled, that's the phenotype. Each critter, each pea baby, has either a smooth seed or a wrinkled seed and that is the pea baby's phenotype in relation to the seed shape. Seed color, you can have a yellow phenotype or a green phenotype. Flower color, purple phenotype, white phenotype. Stem length, tall pea baby, short pea baby. Those are all phenotypes. I want to put the word, I have another one for you. I want to put the word trait up here because this kind of hurts my head and I don't really know how to put this into words. But the phenotype is this specific way that you look, the trait is the characteristic that we're even looking at at all. So without, I mean I need an example. Seed shape is the trait that can show a smoother wrinkled phenotype. Seed color is the trait, eye color is the trait, hair length, I mean not length, hair curliness is the trait. I don't know, how would you describe that? The trait is the, maybe the phenotype is the specific physical characteristic and the trait is also the characteristic, but in general. Like you have a specific phenotype, one or the other. But the trait is the characteristic in general. I hope you know what I mean because I'm not sure if I explained that very well. No, I'm pretty sure I did not explain that very well. If anybody wants to help out, hollow back. The other thing that we need to deal with is a concept called genotype. And your genotype is the alleles that code for your phenotype. So check it out. Your alleles, this is my genotype. This is a genotype. This is a genotype. Genotypes are, there's a couple of things that we need to know about them. Genotypes are diploid. How do you know that this is diploid? Well, all of these, there are two alleles listed, which means there had to be two chromosomes. Do you agree with that? We have one of our chromosomes has a big S and one of them has a little S. And then that's my genotype. Here, one of my chromosomes has a big Y, one of them has a little Y. And that's my genotype. That represents my genotype. Some, your genotype, it is diploid because you're diploid. So we can have a genotype of a sperm or an egg. And in that case, it's going to be haploid, but we'll look at that because we're going to go through meiosis. And if we started out with two Y alleles and then we made a baby, we'd end up with four of them, that's not going to fly. So when we're talking about the critter itself, the grown-up critter or the baby that we are producing from our gametes, we're going to have two letters that represent the genotype. Now, genotypes can have two forms. We can have a heterozygous genotype. And that, so a genotype can be heterozygous if there are two different alleles. The genotype can be homozygous if the alleles are the same. Does that make sense? Now, this leads to our last concept, and that is heterozygous and homozygous describe the genotype. The last concept relates to dominant versus recessive. Dominant alleles are expressed. If you've got a dominant allele, you express it. That means that a heterozygous critter that has a dominant allele will express that dominant allele. So in all our examples, now there's complexity to this that we're not going to talk about yet. Usually, we show our dominant allele as a capital letter, and in this case, the smooth seed shape is dominant over the wrinkled seed shape. This little genotype has a recessive wrinkled seed allele, but it's not expressed because the dominant allele is expressed. So, dominant alleles are expressed in the way that the recessive allele works. Recessive alleles require two copies for expression. So if you're going to express the recessive trait of a wrinkled seed, then you need two little s-copies of the allele, one from mom, one from dad. You have to remember your meiosis in order for any of this to make sense. That's a lot of terminology. So go back and say, okay, seriously, phenotype, trait, genotype, make sure you've got those down. Heterozygous, homozygous, get those down. Recessive and dominant, make sure those are super clear, and make sure you're comfortable with diploid versus haploid. Now, we're going to make a pee baby. We're going to carry out a cross like Mendel did, and just look at the whole process and see if we can figure out the observations that he made after making his crosses. Pee babies, coming up.