Evolution Discussion 1

 Week 1: Fact Or Theory?

    Evolution is the steady change over time in all organisms and it also suggests that we are all somehow related/come from the same original source of life. We don't know what that origin of all life is, but we're able to assume that it exists, given that we have seen examples that we're connected, that we came from one common ancestor. For instance, we can see that humans, dogs, cats (any vertebrate like us that has four legs/limbs), birds (or any flying vertebrate), whales, and so on all share similarly structure forelimbs (can't call them forearms since they don't technically have arms, right?). It's an everyday example - called a homologous structure - that many of us have in common, and it also ties back into the tetrapod, Ichthyostega, whose fossil indicates that this four-legged animal (basically a four-legged fish) was the first one to actually drag itself onto land. It's one of my more favorite examples for evolution and how we're connected (it's pretty easy to remember).

    That being said, I don't think we can call it a fact. Evolution is only a theory because we can't prove (beyond the shadow of a doubt) that it's true. Like someone mentioned in one of the discussion posts, we know for a fact that all life is evolving because we can witness it on a microevolutionary level as well. For example, bacteria's ability to evolve in order to resist antibiotics. Bacteria has been around for millions (billions?) of years, evolving with us and other organisms. Antibiotics weren't discovered nor distributed for use until the early-mid 1900s, so in that short time since antibiotics were developed, bacteria has adapted and evolved to become resistant to it.