Homology, hierarchy and swimming sea slugs

Compare your arm to the arm of a monkey or the foreleg of a cat and you’ll probably find it as no surprise that they’re made up of similar bones arranged in similar ways. A commonplace observation for us, but for Darwin and other early naturalists, these similarities offered proof for the theory of evolution. The bones in our arms and the bones in the forelimbs of other vertebrates are organized in similar ways because they evolved from a common forelimb structure that was present in the ancestor of all tetrapods. The idea that similar traits in disparate species are related through evolutionary history is commonly referred to as homology, a termed coined by the 19th century comparative anat

Sex Life Left You with Dissatisfaction? There’s a gene for that.

Just to clarify, I must be honest and say that this article is not intended to tell you about the genes that control your sex life. If you’re having intimacy problems, you probably won’t find a gene therapist to fix it. Instead, I am going to tell you about fruit flies called Drosophila. They have a sex life too, you know. But before I delve into the details of fruit flies, their genes, and their issues with intimacy, let’s backtrack a bit. Most people would think that behaviors are generally learned. After all, we learn how to eat and how to act properly in society based on prior social interactions, observations, and cues. However, genes can also cause us to act on certain feelings with sp