I would appreciate some help explaining some things about evo-devo. The way it's presented in class makes no sense at all. I have desperately tried wikipedia but it just did NOT help in explaining anything. Would appreciate some elucidation on my questions from the great physics forums... So to start: 1. De Baer's law, explaining why embryos are similar in early development. Please tell me if I'm right. My explanation is that changes to embryos are likely to become large fundamental changes that are deleterious. As a result embryonic development is strongly conserved. For instance, a small change in embryonic physical features can just end up resulting in outright death. However these are some of my classmate's responses... Are they necessarily right or better? -Animals resemble one another in early development- as they develop they look more and more different (Wait, is this even a reason? Am I missing something here) And also, what does morphological similarity have to do with this...? There are a few answers under the sub-heading of morph. similarity, but I don't exactly understand what that has to do with this. 2. Please explain to me the difference between, and what are hox genes and what are homeotic genes? I understand that hox genes are always homeotic genes...? But... so homeotic genes are a special type of gene... but exactly how do they perform what they do? And why are they special? The thing is, I don't know what other types of genes there are, so there's nothing that I've been told saying that not all genes are homeotic, or what genes homeotic genes even affect. I feel I've been given a very bare framework of knowledge. So..... hox genes in: Yeast, animals...? 3. And what do transcription factors have to do with this? I know that they're proteins. I think they are produced by homeotic genes, and they bind to parts of DNA. Is that about it?