Why do animals do what they do? It’s a huge question, and …
Why do animals do what they do? It’s a huge question, and in this episode, we’ll learn how scientists break it down. We’ll talk about the proximate and ultimate studies they use to understand animal behavior, and some of what they’ve learned along the way — including how much decision-making other animals are really doing. Chapters: Introduction: Animal Behavior Proximate Level Ultimate Level Innate Behaviors Complex Behaviors Review & Credits Credits
The world is full of microbes and viruses that can get us …
The world is full of microbes and viruses that can get us sick, but we’ve got an Avengers-style defense system ready to take them on. In this episode of Crash Course Biology, we’ll learn about an animal’s immune system, from their skin to inflammatory responses, to the adaptive immune system and all the special cells and antibodies that come with it. Chapters: Introduction: Defending Against Pathogens The Integumentary System Internal Defenses Asymptomatic Infections Healing Adaptive Immunity & Vaccines The Lymphatic System Review & Credits Credits
When you think about the body’s infrastructure, you probably think of bones. …
When you think about the body’s infrastructure, you probably think of bones. But what about the heart, the blood vessels, and the lymphatic system? In this episode of Crash Course Biology, we’ll tour the cardiovascular, lymphatic, and musculoskeletal systems, learning how all of them keep a vertebrate’s inner workings connected, powered up, and ready to move. Chapters: Introduction: The Body's Infrastructure Blood Vessels & Capillaries The Heart Vivien Thomas The Lymphatic System The Musculoskeletal System Review & Credits Credits
Bacteria often get a bad rap, but they’re some of our best …
Bacteria often get a bad rap, but they’re some of our best partners in science and medicine! In this episode, we’ll explore what bacteria are doing with their DNA — including how they can trade it around. We’ll learn about chromosomes and plasmids, gene expression and recombinant DNA, and how E. coli are used to make insulin. Chapters: Introduction: The Microbiome Prokaryotes & DNA Plasmids & Horizontal Gene Transfer Insulin Gene Expression Dr. Rebecca Lancefield Review & Credits Credits
On its own, a huge DNA sequence is a meaningless pile of …
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 scientists have used it to better understand everything from evolution to a viral epidemic. Chapters: Introduction: Pizza Data Bioinformatics Algorithms The Human Genetic Code The BRCA1 Gene Transcriptomes The Zika Virus Bioinformatics & Programming Review & Credits Credits
Everywhere you look on Earth, you’ll find wonderful and diverse living things, …
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 Course Biology, we reveal how the evolutionary relationships between living things define their place on a single, great Tree of Life, and we learn what that tree can tell us about our own place among the planet’s biodiversity.
Chapters: Ravens & Rhinos The Tree of Life Prokaryotes Eukaryotes Plants Fungi Animals Review & Credits Credits
Biology connects all of life—all of YOUR life. In the final episode …
Biology connects all of life—all of YOUR life. In the final episode of Crash Course Biology, Dr. Sammy is taking your questions. No matter how big, small, or personal, biology is in them all! He’ll show us how biology can help us solve problems and understand everyday life. Chapters: Introduction: Biology and You Stress Response Ecological Niches Water Solvency Unity of Life Biology as a Career Evolution Final Review & Credits Credits
Despite the diverse appearance and characteristics of organisms on Earth, the chemicals …
Despite the diverse appearance and characteristics of organisms on Earth, the chemicals that make up living things are remarkably similar, often identical. In this episode of Crash Course Biology, we’ll look at the building blocks of the four major classes of biomolecules, how those join up to form macromolecules, and how a team of six atoms forms the vast majority of living matter.
Chapters: Introduction to Life’s Molecules Chemical Bonds The Major Biological Molecules Polymerization Hydrolysis Review & Credits Credits
The cell membrane is a protein-studded phospholipid bilayer that not only protects …
The cell membrane is a protein-studded phospholipid bilayer that not only protects our cells, but also regulates what goes in and out. In this episode of Crash Course Biology, we’ll look at the structure of the bilayer, learn about its discovery, and explore the many ways substances can be transported into and out of cells.
Chapters: Introduction to the Cell Membrane Membrane Structure Membrane Proteins Membrane Transport Review & Credits Credits
You know ‘em, you love ‘em. They’re the powerhouse of the cell: …
You know ‘em, you love ‘em. They’re the powerhouse of the cell: mitochondria. They produce the ATP molecules that we use to do everything from talk to our friends to run a marathon. In this episode of Crash Course Biology, we’re taking a deep dive into cellular respiration, the process that produces the ATP inside of our mitochondria.
Chapters: Getting Energy Mitochondria & ATP Cellular Respiration Glycolysis The Citric Acid Cycle The Electron Transport Chain Review & Credits Credits
Cells need energy to power the chemical reactions that keep their microscopic …
Cells need energy to power the chemical reactions that keep their microscopic cities running, and most of that energy comes from a chemical called ATP. In this episode of Crash Course Biology, we’ll learn how our cells use energy, what an enzyme’s role is in chemical reactions, and what makes a reaction exergonic or endergonic.
Chapters: Cellular Cities What Is Energy? The Laws of Thermodynamics ATP Chemical Reactions Enzymes Metabolic Pathways Review & Credits Credits
Community ecology is the study of interactions between different species of living …
Community ecology is the study of interactions between different species of living things, and lets ecologists examine the effects of predator-prey relationships, parasites, and mutually beneficial interactions. In this episode of Crash Course Biology, we’ll examine the myriad interspecies interactions with examples, see how keystone species impact their environment and explore how communities rebuild when they are disrupted, through the lens of the 1980 eruption of Mount St. Helens.
Chapters: Community Ecology Community Disturbances Interspecies Interactions Competition Community Regulation Review & Credits Credits
Some scientists believe we are in the middle of Earth’s sixth mass …
Some scientists believe we are in the middle of Earth’s sixth mass extinction: a big, precarious game of Jenga that involves every ecosystem on the planet. In this episode of Crash Course Biology, we’ll see how conservation biology aims to restore habitat and preserve biodiversity. Along the way, we’ll see how environmental damage impacts human communities, and learn about wolves’ return to Yellowstone National Park.
Chapters: Introduction to Conservation Biology Human Impact Environmental Injustices Restoration Ecology Conservation Review & Credits Credits
Your DNA contains all the instructions your body needs to function. In …
Your DNA contains all the instructions your body needs to function. In this episode of Crash Course Biology, we’ll figure out what this giant instruction manual looks like and how this three-billion-letter code gets copied into your trillions of cells through DNA replication. Chapters: Introduction: DNA & The Human Genome The Structure of DNA Chromosomes DNA Replication How DNA Replication Works Mutations The Okazakis Review & Credits Credits
Climate change shakes up all of Earth’s systems, including the living ones. …
Climate change shakes up all of Earth’s systems, including the living ones. In this episode of Crash Course Biology, we’ll see how climate change’s effects rattle the entire chain of life. Changes felt in one population ripple out to affect entire communities and ecosystems—whether they’re composed of pine trees, puffins, or people.
Chapters: A Changing Climate Ecosystem Effects Ecosystem Responses Increased Carbon Dioxide Effects on Society Review & Credits Credits
Humans may have been around for a long time, but life has …
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 leaps where life diversified, changed, and just plain persisted.
Introduction: How Life Began Macroevolution RNA & DNA The Timeline of Life Stromatolites & Fossils Dr. Meeman Chang Drivers of Macroevolution Review & Credits Credits
We tend to think life fits in two tidy categories: male or …
We tend to think life fits in two tidy categories: male or female, XX or XY. But it’s so much more diverse and complicated! In this episode of Crash Course Biology, we’ll discover sex and sexuality as a continuum across life. We’ll learn why humans are the only species with gender, and why same-sex mating is more common than you might think. Chapters: Introduction: Sex & Gender in Humans How Sex and Gender are different Sex development Differences in sex development What is sexuality Non-human diversity in sexuality Review & Credits Credits
Science fiction is full of superpowered mutants, but in reality, mutations are …
Science fiction is full of superpowered mutants, but in reality, mutations are much more diverse and complex. Sometimes, they can change someone’s entire body, and other times, we don’t notice them at all! In this episode, we’ll unpack what mutations are, how they work (including substitutions and frameshift mutations), and how scientists are learning to control mutations using tools like CRISPR/Cas9 and gene therapy. Chapters: Introduction: Mutations Outside the Movies What Are Mutations? What Determines Mutations' Effects? Types of Mutations Positive, Negative, or Neutral? Gene Therapy & CRISPR Pharmacogenomics Review & Credits Credits
It’s not nature versus nurture—it’s both! In this episode of Crash Course …
It’s not nature versus nurture—it’s both! In this episode of Crash Course Biology, we’ll explore how complex interactions between genes and the environment shape all sorts of traits, from human skin color to honeybees’ “royal jelly.”
Chapters: Nature vs. Nurture Polygenic Traits Complex Traits Epigenetics & Dr. Folami Ideraabdullah Heritability Phenotypic Plasticity Review & Credits Credits
Yep, this is the poop episode. Getting resources and getting rid of …
Yep, this is the poop episode. Getting resources and getting rid of waste is so important, we have three whole systems dedicated to it! In this episode, we’ll learn how the respiratory system, digestive system, and urinary system work, and visit some other animals that process their resources in completely different (and sometimes totally wild) ways. Chapters: Introduction: C. diff The Respiratory System Ingestion & Digestion Absorption & Propulsion Defecation The Urinary System Review & Credits Credits
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