Animal Behavior – CrashCourse Biology #25

Behavior is action in response to a stimulus. My cat Cameo is now responding to both an external stimulus the sound of a bag of treats, and an internal stimulus her hunger, or at least her insatiable desire for treats. Sometimes animal behavior can seem really far out, but if you look closely enough, you Read more…

Complex Animals: Annelids & Arthropods – CrashCourse Biology #23

Hey there, I’m just hanging out with some distant relatives here. I’ve got to say I’ve got a lot of respect for these guys, because they are some of the most successful organisms on the earth. We think we run things on this planet, but we don’t. They do. On one acre of cultivated land, Read more…

Chordates – CrashCourse Biology #24

Next time someone asks you who you think you are, just give them the facts. You’re a mammalian amniotic tetrapodal sarcopterygiian osteichthyan gnathostomal vertebrate cranial chordate. Yeah, it’s a mouthful. And in order to understand what it means, you’re going to have to understand the most complex group of animals on earth, and what it Read more…

Taxonomy: Life’s Filing System – Crash Course Biology #19

Taxonomy! It’s the science of classifying living things. That sounds exciting. Today we’ll basically be learning the Dewey Decimel System of evolution! It’s like filing! You must be on the edge of your seat. OK, shut up. When it comes down to it, this science doesn’t just categorize organisms, when you look a little deeper, Read more…