Table of Contents Introduction The importance of evolution to the study of biology was stated best by Theodosius Dobszhansky, who said, "Nothing in biology makes any sense except in the light of evolution. The forces that drive changes in species are vital to an understanding of life itself.
Carrier Gene Fitness Phenotype Darwin Genetics Natural selection Genotype Allele Evolution Genetic variation Heredity Video transcript I think what is probably the most misunderstood concept in all of science, and as we all know is now turning into one of the most contentious concepts, maybe not in science, but in our popular culture, and that's the idea of evolution.
Whenever we hear this word, I mean, even if we don't hear it in the biological context, Introduction to evolution imagine that something is changing, it is evolving. And so when people use the word evolution in our everyday context, they think of this notion of change, Introduction to evolution this is going to test my drawing ability-- but you see an ape bent over.
We've all seen this picture at the natural museum, and he's walking hunchback like that, and his head's bent down and-- oh, I'm doing my best. Maybe he's also wearing a hat.
And then they show this picture where he slowly, slowly becomes more and more upright, and eventually, he turns into some dude, who's just walking on his way to work, also just as happy, and now he's walking completely upright. And it's some kind of implication that walking upright is better than not walking upright, et cetera, et cetera.
Oh, he doesn't have a tail anymore. Let me eliminate that. This guy does have a tail. Let me do it in an appropriate width.
This guy has a tail, so you're going to have to excuse my drawings skills, but we've all seen this. If you've ever gone to a natural history museum, and they'll just make more and more upright apes, and eventually you get to a human being, and it's this idea that the apes somehow changed into a human being.
And I've seen this in multiple contexts, even inside of biology classes and even the scientific community. They'll say, oh, the ape evolved into the human or the ape evolved into the pre-human, the guy that almost stood upright, the guy that was a little bit hunchback, so he looked a little bit like an ape and a little bit like a human and so on and so forth.
And I want to be very clear here. Even though this process did happen, that you did have creatures that over time accumulated changes that maybe their ancestors might have looked more like this, and eventually they looked more like this, there was no active process going on called evolution.
It's not like the ape said, gee, I would like my kids to look more like this dude, so somehow, I'm going to get my DNA to get enough changes to look more like this.
And it's not like the DNA knew. The DNA didn't say, hey, it is better to be walking than to be kind of hunchbacked like an ape. And so therefore, I'm going to try to somehow spontaneously change into this dude.
That's not what evolution is.
It's not like-- you know, some people imagine that maybe there was a tree. There's a tree, and on that tree, there's a bunch of good fruit at the top of the tree. And then maybe you have some type of cow-like creature, or maybe it's some type of horse-like creature that says, gee, I would like to get to those apples, and that just because they want to get there, maybe the next generation-- they keep trying to raise their neck, and then after generation after generation, their necks get longer and longer, and eventually they turn into giraffes.
That is not what evolution is and that's not what it implies, although sometimes the everyday notion of the word seems to make us think that way. What evolution is-- and actually, this is the word that I prefer to use-- it's natural selection. Let me write that word down. And literally, what it means is that in any population of living organisms, you're going to have some variation, and this is an important keyword here.
Evolution NARRATOR: Ok, go to the window. Or better yet, step outside. A squirrel darts past. Trees and weeds surge up towards the sky. Birds tickle the air. Get down on the ground and there’s more—worms wriggling, mushrooms sprouting, beetles crawling. There’s . INTRODUCTION TO EVOLUTION; Hopefully, you have arrived here after dealing with the topics suggested in the overall unit sequence plan (nature of science, survey of the diversity of life, biological classification, a comparison of fossil hominin skulls, and some questions raised from those experiences).ALTERNATIVELY, you may prefer to introduce the topic of evolution directly, or at least . Human evolution. Human evolution is the lengthy process of change by which people originated from apelike ancestors. Scientific evidence shows that the physical and behavioral traits shared by all people originated from apelike ancestors and evolved over a period of approximately six million years.
Variation just means, look, there's just some change. If you look at the kids in your school, you'll see variation.
Some people are tall, some people are short, some people have blond hair, some people have black hair, so on and so forth. And what natural selection is is this process that sometimes environmental factors will select for certain variation. Some variations might not matter at all, but some variations matter a lot.Evolution is change over time.
Under this broad definition, evolution can refer to a variety of changes that occur over time—the uplifting of mountains, the wandering of riverbeds, or the creation of new species. To understand the history of life on Earth though, we need to be more specific about.
It includes an entirely new chapter focused on human evolution, for example, as well as discussions of additional concepts in evolution, new illustrations, and descriptions of new research. Richly illustrated with drawings and photographs, The Tangled Bank is essential reading for anyone who wants to understand the history of life on Earth/5(7).
Evolution is the unifying force in modern biology, but it remains a source of misunderstanding and controversy. Start finding out why it is so important with our beginner's guide. Introduction To Evolution What is Evolution? Evolution is the process by which all living things have developed from primitive organisms through changes occurring over billions of years, a process that includes all animals and plants.
This is a brief introduction to evolutionary biology. I attempt to explain basics of the theory of evolution and correct many of the misconceptions.
What is Evolution? Evolution NARRATOR: Ok, go to the window. Or better yet, step outside. A squirrel darts past. Trees and weeds surge up towards the sky.
Birds tickle the air.