In this video Paul Andersen explains how scientific theories are created and modified over time. He starts by discussing the theory of natural selection as a model for the creation and modification of theories. He gives examples of...

Paul Andersen introduces the topic of Biology. He covers each of the four main ideas that were developed by the College Board. These ideas revolve around the concepts of evolution, free energy, information and systems.

Paul Andersen shows how homeostasis reflects of evolution through time. The endocrine system shows continuity through flatworms, earthworms and vertebrates. However the respiratory system shows change as organisms move onto land. The...

There are a whole lot of people out there who have bought into the notion that, in order to be physically fit, you should aim for taking 10,000 steps a day. But where did this idea come from, and how did we all agree on this magical,...

MOT 1952: 19th CENTURY GAMBLER: 'Jack O'Diamonds' character dressed in historic, professional gambler clothing, sitting at poker table flipping cards w/ hands while explaining who he is & giving clue to what he does for living.

Whether we’re talking about tigers, trees, or tarantulas, evolution happens at the level of the population. In this episode of Crash Course Biology, we’ll find out how natural selection, gene flow, genetic drift, and other processes...

There are lots of ways that evolution happens, and natural selection is just one of them. In this episode of Crash Course Biology, we’ll find out how this process works and shapes traits in all living things —from ginkgo trees to howler...

In this episode of Crash Course Biology, we’ll learn about the ways population genetics reveals how groups of living things evolve—by comparing genetic similarities and differences. We’ll discover the most genetically diverse species of...

What’s a human? And how did we become humans, anyway? In this episode of Crash Course Biology, we’ll meet some of our closest relatives and trace how we evolved into the brainy, inventive, complex species we are today.

Everywhere you look on Earth, you’ll find wonderful and diverse living things, from tiny tardigrades to soaring sequoias. And incredibly, everything alive today, and everything that’s ever lived, is related. In this episode of Crash...

How can you tell two species apart? It’s not always simple. In this episode of Crash Course Biology, we’ll learn about speciation—a process that can happen over millions of years, or within a single generation. Along the way, we’ll...

Crocodiles, and birds, and dinosaurs—oh my! While classifying organisms is nothing new, phylogeny— or, grouping organisms by their evolutionary relationships—is helping us see life in a whole new light. In this episode of Crash Course...

Humans may have been around for a long time, but life has existed for way longer. In this episode of Crash Course Biology, we’ll journey through deep time to uncover the history of life on Earth. We’ll explore the big, game-changing...

Paul Andersen describes microevolution and macroevolution in the stickleback fish of Loberg Lake. He describes how anadramous fish repopulated the lake after poisoning and adapted to the new environment through natural selection. He...

Howcast - Learn how to pet or massage your cat from board-certified veterinary behaviorist Dr. E'Lise Christensen, DVM in this Howcast video.

Howcast - Learn how to animate found objects from Joe Vena of the Children's Museum of the Arts in this stop motion tutorial from Howcast.

Pupil outcome: I can explain the story that the poem tells, as well as how the poem is used as a metaphor. Key learning points: - Seamus Heaney's 'Death of a Naturalist' tells the story of a young child who frequents a flax-dam to...

Howcast - Learn the basics of claymation from Joe Vena of the Children's Museum of the Arts in this stop motion animation tutorial from Howcast.

Howcast - Learn how to animate water from Joe Vena of the Children's Museum of the Arts in this stop motion tutorial from Howcast.

Howcast - Learn about board-certified veterinary behaviorist Dr. E'Lise Christensen, DVM, one of Howcast's cat experts, in this video.

Howcast - Learn how to clip your cat's nails from board-certified veterinary behaviorist Dr. E'Lise Christensen, DVM in this Howcast video.

Pupil outcome: I can explore how Lady Macbeth’s feelings of guilt change over the course of ‘Macbeth’. Key learning points: - Lady Macbeth appears to be suffering from a psychological disorder that causes her to sleep-walk - This...

On its own, a huge DNA sequence is a meaningless pile of data — so, how do biologists figure out what it means? They turn to the power of bioinformatics! In this episode, we’ll learn what bioinformatics is, how it works, and how...

Paul Andersen explains how natural selection is a major mechanism in evolution. The video begins with a discussion of Charles Darwin and the details of natural selection. The data of the peppered moth during the industrial revolution...