How big are you? Really?! A couple feet tall, a meter and a half, 36-24-36... There are many ways to identify how big we are. It is all relative, of course. We are 5'7" tall, living in a house, living in a county, in a state, in a country, in a hemisphere, on the Earth, in our solar system, in our tiny part of the galaxy, in a larger galaxy of galaxies, in the seemingly infinitely large and endless expance of that which we call the universe. It's quite synical to point out our insignificance in this manner, but it is humbling at the same time.
Understanding the world around us and our place among the other living organisms on our tiny planet is crucial to life as a human. When we learn about the species and great diversity with which we live, we can gain the awe-inspiring appreciation for the small sector of the universe we inhabit.
Want to see exactly how big you are as compared to an electron, or a dinosaur, or a Sycamore tree, or the Milky Way?! Check out this slide-rule scroll through the dimensions of our universe:
To understand our placement in the natural world, we must first classify ourselves in a way that we can trace our ancestry through evolutionary time. One way we can accomplish this is through systematics, a means of classifying and relating organisms to one another by either morphological or molecular relationships. For example, all animals that have a spinal chord are related due to this shared characteristic, though not all equally. We will be overviewing the many phyla of the invertebrate and vertebrate world based on their shared derived characteristics (characteristics specific to a particular species that are different from their ancestral traits). Let's begin...