If nearly all your cells have the same DNA, why are muscle …
If nearly all your cells have the same DNA, why are muscle cells so different from skin cells? In this episode, we’ll learn how gene expression is regulated in eukaryotes, and how methylating DNA, modifying histones, and messing with translation not only leads to different types of cells, but allows cells to adapt to the world around them. Chapters: Introduction: A Cellular Cookbook Gene Regulation Differential Gene Expression Gene Regulation Strategies Epigenetic Mechanisms Review & Credits Credits
Here on Earth, life is dizzyingly diverse—but it’s also surprisingly organized. A …
Here on Earth, life is dizzyingly diverse—but it’s also surprisingly organized. A sense of order structures life and its processes, from the tiniest cell to the total sum of every living thing. In this episode of Crash Course Biology, we’ll uncover the levels of biological organization, discover soil’s superpowers, and find out why the biosphere is kind of like a really, really long train.
Chapters: Life's Layers Themes of Life Form Fits Function Regulation Levels of Organization Life's Flows Review & Credits Credits
What’s a human? And how did we become humans, anyway? In this …
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.
Chapters: The First Humans What is a Human? Hominins Dr. Xinzhi Wu Hominin Interbreeding How Humans Evolved Review & Credits Credits
Biology is the study of life—a four-letter word that connects you to …
Biology is the study of life—a four-letter word that connects you to 4 billion years worth of family tree. The word “life” can be tricky to define, but a shared set of characteristics helps biologists identify living things. In this episode of Crash Course Biology, you’ll learn how all of life is connected, and why studying biology can help us better understand ourselves and our relationship to all living things.
Chapters: Welcome to Crash Course Biology! Life's Characteristics Is a Virus Alive? Life Beyond Earth Biology and You All Life is Connected Review & Credits Credits
Ecology is the study of the interactions of living things with each …
Ecology is the study of the interactions of living things with each other and their environment. It’s a field that not only lets us explore the interconnections between living things, but also how our environment affects us, and how we influence it in turn. In this episode of Crash Course Biology, we’ll get an overview of the field of ecology, see how matter and energy are conserved and transferred through ecosystems, and follow an ecological mystery surrounding the deaths of hundreds of elephants in Botswana, Africa.
Chapters: An Ecological Mystery Biotic & Abiotic Factors Ecosystems Fields of Ecology Trophic Levels Energy Flow through Ecosystems Review & Credits Credits
From a single-celled common ancestor, evolution has brought us all of Life’s …
From a single-celled common ancestor, evolution has brought us all of Life’s Greatest Hits — including butterflies, beetles, bacteria, and human beings. In this episode of Crash Course Biology, we’ll learn how evolution explains life’s unity and diversity. Along the way, we’ll explore the fishy origins of a giraffe’s neck, and find out what a cat’s paw and your own arm have in common.
Chapters: Where Whales Came From What Is Evolution? Genetic Mutations Adaptations & Trade-offs Evidence of Evolution Unicellularity vs. Multicellularity Did Humans Evolve From Monkeys? Review & Credits Credits
How do traits get passed down in our DNA? And what do …
How do traits get passed down in our DNA? And what do genes have to do with cat fur? In this episode of Crash Course Biology, we’ll untangle the simplest patterns of inheritance, and reassure our redheaded friends—you’re not going anywhere.
Chapters: Are Redheads Going Extinct? Alleles & Traits Patterns of Inheritance Autosomal Dominance Incomplete Dominance Codominance Review & Credits Credits
Whether we’re talking about tigers, trees, or tarantulas, evolution happens at the …
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 drive changes in populations. We’ll learn about the Hardy-Weinberg equation, how your alleles make you uniquely you, and how some tigers changed their stripes.
Chapters: When Black Bears Are White Genes & Alleles Natural Selection Genetic Drift Gene Flow The Hardy-Weinberg Equation Review & Credits Credits
There’s an immense world of tiny stuff within us and around us—but …
There’s an immense world of tiny stuff within us and around us—but how do we know about it? In this episode of Crash Course Biology, we’ll discover how we see what we can’t see, thanks to the help of centuries-old tools and more recent technology. Along the way, we’ll learn about the major types of microscopes and how to use a typical light microscope.
Chapters: Discovering Bacteria Methods for Observing Molecules Microscopy Types of Microscopes Cryo-Electron Microscopy How Light Microscopes Work Review & Credits Credits
There are countless types of plants and animals on Earth, but how …
There are countless types of plants and animals on Earth, but how do they work? In this episode of Crash Course Biology, we’ll take a bird’s eye view of how multicellular life functions, including how it’s organized, how it regulates itself to maintain homeostasis, and the big question: Why are these living things so wildly complex? Chapters: Introduction: Bizarre Beasts Multicellular Organization Cell Specialization Why We Aren't Unicellular Cons of Multicellularity Dr. Rebeca Gerschman Homeostasis Review & Credits Credits
There are lots of ways that evolution happens, and natural selection is …
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 monkeys. We’ll also learn how extra-grippy toes help some lizards survive hurricanes.
Chapters: How Spiders Stay Alive What's Natural Selection? Requirements for Natural Selection Environmental Effects Types of Natural Selection Evolutionary Trade-Offs Artificial Selection Review & Credits Credits
If cells and organs never talked to each other, an animal would …
If cells and organs never talked to each other, an animal would fall apart faster than a boy band after the popular one goes solo. Thankfully, that’s where the nervous and endocrine systems come in! In this episode of Crash Course Biology, we’ll learn how they use neurons, hormones, and more to keep animals’ bodies coordinated. Chapters: Introduction: Internal communication in animals Why communication matters The nervous system What happens when you step on a Lego? Hormones Fight or Flight Review & Credits Credits
Photosynthesis is a powerful process that is responsible for some of life’s …
Photosynthesis is a powerful process that is responsible for some of life’s most vital functions. In fact, consumers like us rely on photosynthetic producers to harness energy from the sun so that we can survive and thrive. In this episode of Crash Course Biology, we’ll explore photosynthesis in two acts, and learn how the process works inside and out.
Chapters: How Can We Feed the World? Producers & Photosynthesis Chloroplasts The Light-Dependent Reactions The Calvin Cycle Carbon Fixation Review & Credits Credits
Crocodiles, and birds, and dinosaurs—oh my! While classifying organisms is nothing new, …
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 Biology, we’ll learn why this kingdom-phylum stuff is going out of style and why phylogenetic trees are in.
Chapters: The Platypus & Phylogeny Taxonomy Systematics Phylogeny & Genetics Dr. Motoo Kimura Phylogenetic Trees The Complexities of Evolution Review and Credits
Plants may not seem like they’re doing much, but if you look …
Plants may not seem like they’re doing much, but if you look closer, you’ll find a whole world just lurking beyond the surface. We’re talking chemical defenses, highways, and even ways to change the weather. In this episode, we’ll learn how plants get resources, get rid of waste, stay defended, govern themselves, and much more. Chapters: Introduction: How Plants Work Meet the angiosperms How plants transport nutrients How plants eliminate waste Plant defenses Plant Communication and Reproduction Review & Credits Credits
When the Bald Eagle population started to decline in the mid-20th century, …
When the Bald Eagle population started to decline in the mid-20th century, scientists began to ask why. Population ecology, the study of organisms of the same species, played a big role in answering that question. In this episode of Crash Course Biology, we’ll take a look at the methods population ecologists use to study a population and the types of data they collect. We’ll also find out how scientists helped bring the Bald Eagle back from the brink.
Chapters: Introduction to Population Ecology Density Dispersion Demographics Population Growth Review & Credits Credits
In this episode of Crash Course Biology, we’ll learn about the ways …
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 all (hint: it’s not us), find out why “race” isn’t the biologically valid category we’ve made it out to be, and learn there’s much more in our DNA that we share than that sets us apart.
Chapters: Population Genetics Genetic Diversity Levels of Genetic Diversity Melanin Variation Clines & Ancestry Race & Society Review & Credits Credits
When it comes to animal reproduction, there’s no one-size-fits-all strategy. Some animals …
When it comes to animal reproduction, there’s no one-size-fits-all strategy. Some animals need a mate, others don’t, and for some, it depends! In this episode, we’ll learn about sexual and asexual reproduction, internal and external fertilization, and all the ways that life, uh… finds a way. Chapters: Introduction: Reproduction Asexual reproduction Sexual Reproduction Fertilization Sexes Review & Credits Credits
How can you tell two species apart? It’s not always simple. In …
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 discover how a single species can split into two and how a reptile from New Zealand continues to stump scientists.
Chapters: A Living Fossil Species & Evolution Species Concepts What Separates Species Allopatric Speciation Sympatric Speciation Review & Credits Credits
You’ve probably heard of mRNA, thanks to the COVID-19 vaccine. But what …
You’ve probably heard of mRNA, thanks to the COVID-19 vaccine. But what is mRNA exactly? In this episode of Crash Course Biology, we learn about the role of messenger RNA in living things and how it decodes our DNA instruction manual through transcription. Chapters: Introduction: mRNA Vaccines Messenger RNA Transcription Processing & Splicing The Central Dogma Alternative Splicing Review & Credits Credits
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