NaN/100 votes#1 - Introduction to Biology
Season 2 Episode 1 - Aired 6/6/2023
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.
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#2 - The Scientific Method
Season 2 Episode 2 - Aired 6/13/2023
Science offers a way of discovering and understanding the world around us, driven by questions and tested with evidence. And it’s a twisty-turny team effort— you won’t find many lone geniuses out there, or straight lines from hypothesis to conclusion. In this episode of Crash Course Biology, we’ll talk about the big picture of how scientific progress is made, from peer review to mathematical models, with some exploding eggs along the way.
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#3 - What Biologists Do
Season 2 Episode 3 - Aired 6/27/2023
A biologist’s natural habitat is anywhere questions about life are being asked—whether the subject is a nematode or a narwhal, a single cell, or a whole ecosystem. In this episode of Crash Course Biology, we’re flipping the microscope around to show how biologists’ work goes down. Along the way, we’ll learn why zebrafish and fruit flies are some of biology’s next top models.
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#4 - How Life is Organized
Season 2 Episode 4 - Aired 7/11/2023
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.
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#5 - Why Did All These Elephants Die? (Intro to Ecology)
Season 2 Episode 5 - Aired 7/18/2023
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.
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#6 - How Species Make and Break Friendships (Community Ecology)
Season 2 Episode 6 - Aired 8/1/2023
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.
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#7 - How Did We Save The Bald Eagle? (Population Ecology)
Season 2 Episode 7 - Aired 8/8/2023
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.
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#8 - What Is Climate Change?
Season 2 Episode 8 - Aired 8/15/2023
Life on Earth has weathered boiling-hot oceans and volcanic-ash-darkened skies—but that’s nothing like the climate change we’re experiencing now. In this episode of Crash Course Biology, we’ll talk about the greenhouse effect, learn why our climate is like a tangled pair of headphones, and discover that we’ve understood the science behind climate change for much longer than you might think.
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#9 - The Effects of Climate Change
Season 2 Episode 9 - Aired 8/22/2023
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.
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#10 - How Do We Keep Life's Jenga Tower From Toppling? (Conservation Biology)
Season 2 Episode 10 - Aired 8/29/2023
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.
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#11 - What a weirdly long giraffe nerve can teach us about evolution
Season 2 Episode 11 - Aired 9/5/2023
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.
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#12 - Microevolution: What's An Allele Got To Do With It?
Season 2 Episode 12 - Aired 9/12/2023
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.
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#13 - Natural Selection: Life's Way of Stayin' Alive
Season 2 Episode 13 - Aired 9/19/2023
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.
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#14 - Why do we have different skin colors? (Population Genetics)
Season 2 Episode 14 - Aired 10/4/2023
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.
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#15 - Where Do Species Come From? (Speciation)
Season 2 Episode 15 - Aired 10/10/2023
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.
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#16 - How did life begin? (Evolutionary History)
Season 2 Episode 16 - Aired 10/17/2023
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.
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#17 - How We're All Related (Phylogeny)
Season 2 Episode 17 - Aired 10/24/2023
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.
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#18 - Humans Develop Butt First (and other insights from the Tree of Life)
Season 2 Episode 18 - Aired 10/31/2023
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.
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#19 - Humans Didn't Evolve From Chimps (Human Evolution)
Season 2 Episode 19 - Aired 11/7/2023
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.
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#20 - What is Life Made of? (Carbon & Biological Molecules)
Season 2 Episode 20 - Aired 11/14/2023
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.
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#21 - A Love Letter to H2O: Water & pH
Season 2 Episode 21 - Aired 11/28/2023
This is a love letter to water, life’s solvent, and one of the most wonderful molecules around. In this episode of Crash Course Biology, we’ll learn about how water’s polarity and hydrogen bonding help it sustain life on a larger scale. We’ll see how some water-based solutions can be acidic or basic, and examine how our bodies maintain the narrow pH range necessary for life.
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#22 - How We See What We Can't See (Microscopes)
Season 2 Episode 22 - Aired 12/5/2023
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.
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#23 - A Tour of the Cell
Season 2 Episode 23 - Aired 12/12/2023
The cell is the basic unit of life, and our understanding of it has advanced as science, and the tools available to scientists, has advanced. In this episode of Crash Course Biology, we’ll take a look at the difference between prokaryotic and eukaryotic cells, take a guided tour of the eukaryotic cell, and learn why most cells are small. We’ll explore the eukaryotic cell’s surprising beginnings through an endosymbiosis that occurred about 1.5 billion years ago.
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#24 - How Does Stuff Get Into Your Cells? (Cell Membranes)
Season 2 Episode 24 - Aired 12/19/2023
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.
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#25 - How Do Cells Communicate? (Cell Communication)
Season 2 Episode 25 - Aired 1/9/2024
Even though it might seem like our bodies are on autopilot, there is a whole lot happening inside us to keep things moving. In this episode of Crash Course Biology, we’ll learn that our cells are in constant communication, reminding each other—and themselves—to perform important functions like breathing, walking, or even sleeping.
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The Best Episodes of Crash Course Biology Season 2
Every episode of Crash Course Biology Season 2 ranked from best to worst. Discover the Best Episodes of Crash Course Biology Season 2!
And thus begins the most revolutionary biology course in history. Come and learn about covalent, ionic, and hydrogen bonds. What about electron orbitals, the octet...
Genre:Documentary
Network:YouTube
Season 2 Ratings Summary
"Introduction to Biology" is the best rated episode of "Crash Course Biology" season 2. It scored N/A/10 based on 0 votes. Directed by N/A and written by N/A, it aired on 6/6/2023. This episode is rated NaN points higher than the second-best, "The Scientific Method".