Population ecology is the study of groups within a species that interact mostly with each other, and it examines how they live together in one geographic area to understand why these populations are different in one time and place than they are in another. How is that in any way useful to anyone ever? Hank uses the example a of West Nile virus outbreak in Texas to show you in this episode of Crash Course: Ecology.

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Table of Contents
1) Density & Dispersion 02:03
2) Population Growth 03:07
3) Limiting Factors 03:45
a) Density Dependent 06:16
b) Density Independent 07:11
4) Exponential & Logistical Growth 08:04
5) How to Calculate Growth Rate 09:33

References:
http://www.latimes.com/news/na....tion/nationnow/la-na
http://www.dshs.state.tx.us/id....cu/disease/arboviral
http://en.wikipedia.org/wiki/Mosquito
http://www.nature.com/scitable..../knowledge/library/p
Campbell Biology 9th ed. Support CrashCourse on Subbable: http://subbable.com/crashcourse

If you want to make a movie, generally you're going to want to start with a script. In this episode of Crash Course Film Production, Lily Gladstone talks about the basics of screenplays and how to get started thinking about and actually writing your movie.

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***

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This week, we're starting our discussion of Mythical Creatures with the WORST creatures. Monsters. What makes a monster monstrous though? Mike Rugnetta will guide you through the fine line between a magical creature and a monster. Spoiler alert: like 60% of the time, the difference is that monsters eat people. We'll talk about sea monsters, Sphinxes, and take an elongated look directly into the Canadian face of horror, the Wendigo.

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In which John Green teaches you about the Democratic Republic of the Congo, which used to be Zaire, which used to be The Belgian Congo, which used to be the Congo Free State, which used to be the region surrounding the Congo River Basin in central Africa. So the history of this place is a little convoluted. The history of Congo is central to the history of central Africa, and the Congo Wars embroiled neighboring countries like Uganda and Rwanda. John will talk you through the history of Congo and the region.

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Citation 1: David van Reybrouck, Congo: The Epic History of a People. Trans. Sam Garrett. Harper Collins. 2014.
Citation 2: van Reybrouck. p 468

So today Craig is going to look at political ideology in America. We're going to focus on liberals and conservatives and talk about the influencers of both of these viewpoints. Now, it's important to remember that political ideologies don't always perfectly correspond with political parties, and this correspondence becomes less and less likely over time. So, sure we can say that Democrats tend to be liberal and Republicans tend to be conservative, but we're not going to be talking about political parties in this episode. It's also important to note, that there are going to be a lot of generalizations here, as most peoples' ideologies fall on a spectrum, but we're going to try our best *crosses fingers* to summarize the most commonly held viewpoints for each of these positions as they are used pretty frequently in discussions of American politics.

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All attributed images are licensed under Creative Commons by Attribution 4.0

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All the magic that we know is in the transfer of electrons. Reduction (gaining electrons) and oxidation (the loss of electrons) combine to form Redox chemistry, which contains the majority of chemical reactions. As electrons jump from atom to atom, they carry energy with them, and that transfer of energy is what makes all life on earth possible.

**Special Thanks to Matt Young at the University of Montana (Geosciences Department, Environmental Biogeochemistry Lab) who helped with the chemical demonstrations.**

Oxidation 1:42
Reduction 1:03
Oxidation Numbers 3:29
Redox Reactions 5:59
Oxidation Reactions 6:28
Balancing Oxidation Reactions 7:18

Also thank you to the following chemistry teachers for assistance:
James Sarbinoff
Rachel Wentz
Edi González
Lucas Moore
Chris Conley
Addie Clark
Julia Rosinski

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We’re picking up where we left off last time, exploring the “ethics of care” and how it applies to extreme poverty. Are we responding to global poverty in a moral way? Philosophers like Peter Singer argue that we have an obligation to prevent harm caused by poverty, whereas Garrett Hardin offers a “lifeboat analogy” to explain our obligations to focus on caring for our own.

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https://www.oxfam.org
http://www.thelifeyoucansave.org
https://www.againstmalaria.com
http://www.givewell.org/intern....ational/top-charitie

--

Produced in collaboration with PBS Digital Studios: http://youtube.com/pbsdigitalstudios

--

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Hank fills us in on the endocrine system - the system of glands which produce and secrete different types of hormones directly into the bloodstream to regulate the body's growth, metabolism, and sexual development & function.

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References for this episode can be found in the Google document here: http://dft.ba/-1lsU

Table of Contents
1) Signalling Systems 2:07:0
2) Pituitary 3:19:1
3) Hypothalamus 4:17:1
4) Thyroid 4:52:1
5) Adrenal 5:38:1
6) Pancreas 6:51:1
7) Biolography 8:49:2

biology, crash course, crashcourse, hank green, anatomy, physiology, endocrine system, hormone, gland, human, body, science, exocrine, pituitary, thyroid, adrenal, pancreas, gonads, paracrine signalling, autocrine signalling, signal receptor, steroids, peptides, monoamines, brain, hypothalamus, oxytocin, negative feedback loop, kidney, stress, ACTH, epinephrine, organ, glucose, insulin, glucagon, testes, androgen, testosterone, ovaries, estrogen, progestin, estradiol, progesterone, sex, alfred jost, embryologist, secretion, embryonic development, embryo, mammal, fetal development, puberty, reproductive organs Support CrashCourse on Subbable: http://subbable.com/crashcourse

There's a new Crash Course poster with all your favorite World History characters! Czech it: http://store.dftba.com/product....s/crashcourse-charac

In which John Green teaches you about the Mughal Empire, which ruled large swaths of the Indian Sub-Continent from 1526 to (technically) 1857. While John teaches you about this long-lived Muslim empire, he'll also look at the idea of historical reputation and how we view people from history. Namely, he'll look at the reputations of Mughal emperors Akbar I and Aurangzeb. Traditionally, Akbar I is considered the emperor that made the Mughal Empire great, and Aurangzeb gets the blame for running the whole thing into the ground and setting it up for decline. Is that really how it was, though? It turns out, it's complicated.

You can directly support Crash Course at https://www.patreon.com/crashcourse Subscribe for as little as $0 to keep up with everything we're doing. Free is nice, but if you can afford to pay a little every month, it really helps us to continue producing this content.

In today’s episode, Hank asks you to consider all the ways people talk about justice and what we really mean when we use that word. We’ll explain various theories of justice, just distribution, and different approaches to punishment.


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--

All other images and video either public domain or via VideoBlocks, or Wikimedia Commons, licensed under Creative Commons BY 4.0: https://creativecommons.org/licenses/by/4.0/

Produced in collaboration with PBS Digital Studios: http://youtube.com/pbsdigitalstudios

--

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Crash Course World History is now available on DVD! Visit http://store.dftba.com/product....s/crashcourse-world- to buy a set for your home or classroom.

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John Green teaches you about the so-called Dark Ages, which it turns out weren't as uniformly dark as you may have been led to believe. While Europe was indeed having some issues, many other parts of the world were thriving and relatively enlightened. John covers European Feudalism, the cultural blossoming of the Islamic world, and the scientific and artistic advances in China, all during these "Dark Ages." Along the way, John will raise questions about the validity of Europe's status as a continent, reveal the best and worst years of his life, and frankly state that science and religion were once able to coexist.


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How did we get here? Well, in terms of Atomic Chemistry, Hank takes us on a tour of the folks that were part of the long chain of other folks who helped us get to these deeper understandings of the world. From Leucippus to Heisenberg to you - yes, YOU - the story of Atomic Chemistry is all wibbly-wobbly... and amazing.

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Table of Contents

Leucippus, Democritus & Atomic Theory 0:09
Discharge Tubes 1:52
Ernest Rutherford & The Nucleus 4:22
Chemistry = Math 7:22
Niels Bohr Model 5:32
Heisenburg & Quantum Theory 6:35
--
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So today Craig is going to talk about where our political opinions come from. Of course, most people’s politics are grounded in their ideologies, but there are also other external influences such as the government itself, interest groups, and the media. So we're going to talk about how these influencers factor into the overall public opinion and how their roles have changed over time. Now this stuff may seem like common sense, but it’s important to know where our opinions come from, especially when you consider how quickly the media landscape is changing.

Produced in collaboration with PBS Digital Studios: http://youtube.com/pbsdigitalstudios

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All attributed images are licensed under Creative Commons by Attribution 4.0

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So, today we’re talking about African Pantheons. Now, you might say, that’s ridiculous. Africa isn’t a single place with a single pantheon, and we’d be fools to try and cover all that in an eleven minute video. You’d be right. Instead we’re going to focus on Yoruba religion from west Africa, and the Orishas that populate Yoruba stories. The many, many Orishas cover all aspects of life, and can be pretty specialized. We’re going to focus on a dozen or so.

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Why are some countries rich? Why are some countries poor? In the end it comes down to Productivity. This week on Crash Course Econ, Adriene and Jacob investigate just why some economies are more productive than others, and what happens when an economy is mor productive. We'll look at how things like per capita GDP translate to the lifestyle of normal people. And, there's a mystery.

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Mark, Jan Schmid, Simun Niclasen, Robert Kunz, Daniel Baulig, Jason A Saslow, Eric Kitchen, Christian, Beatrice Jin, Anna-Ester Volozh, Eric Knight, Elliot Beter, Jeffrey Thompson, Ian Dundore, Stephen Lawless, Today I Found Out, James Craver, Jessica Wode, Sandra Aft, Jacob Ash, SR Foxley, Christy Huddleston, Steve Marshall, Chris Peters

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In which Craig Benzine teaches you about the US Governments Separation of powers and the system of checks and balances. In theory, the Legislative Branch, the Executive Branch, and the Judicial Brach are designed to keep each other in check, and to keep any branch from becoming too powerful. In reality, the system was designed to keep the president from becoming some kind of autocrat. For the most part, it has worked. Craig will call in the clones to explain which powers belong to which branches, and to reveal some secret perks that the Supreme Court justices enjoy.

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Hank explains the extremely complex series of reactions whereby plants feed themselves on sunlight, carbon dioxide and water, and also create some by products we're pretty fond of as well.

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This video uses sounds from Freesound.org, a list of which can be found, along with the CITATIONS for this episode, in the Google document here: http://dft.ba/-29ai

Table of Contents:
1) Water 1:16
2) Carbon Dioxide 1:32
3) Sunlight/Photons 1:43
4) Chloroplasts 1:57
5) Light Reaction/Light-Dependent 2:42
a. Photosystem II 3:33
b. Cytochrome Complex 5:54
c. ATP Synthase 6:16
d. Photosystem I 7:06
6) Dark Reactions/Light-Independent 7:55
a. Phase 1 - Carbon Fixation 8:50
b. Phase 2 - Reduction 11:31
c. Phase 3 - Regeneration 12:02

tags: photosynthesis, biology, science, crashcourse, plants, light, calvin cycle, respiration, water, carbon dioxide, sunlight, xylem, time lapse, stomata, chlorophyll, photon, plastid, chloroplast, oxygen, thylakoid, grana, lumen, stroma, chemistry, fusion, photoexcitation, photosystem II, electron transport chain, protein, cytochrome complex, carbon fixation, rubisco, phosphoglycolate, reduction, regeneration, glyceraldehyde 3-phosphate, G3P, glucose, cellulose, starch, life Support CrashCourse on Subbable: http://subbable.com/crashcourse

Today, Carrie Anne is going to take a look at how those transistors we talked about last episode can be used to perform complex actions. With the just two states, on and off, the flow of electricity can be used to perform a number of logical operations, which are guided by a branch of mathematics called Boolean Algebra. We’re going to focus on three fundamental operations - NOT, AND, and OR - and show how they were created in a series of really useful circuits. And its these simple electrical circuits that lay the groundwork for our much more complex machines.

*CORRECTION* AT 1:27 the graph says "Quinary System" but then the graph shows 10 possible states - which is actually decimal. Technically, there should be only 5 possible values there, but the overall concept is still the same.


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What is a trade deficit? Well, it all has to do with imports and exports and, well, trade. This week Jacob and Adriene walk you through the basics of imports, exports, and exchange. So, you remember the specialization and trade thing, right? So, that leads to imports and exports. Economically, in the aggregate, this is usually a good thing. Globalization and free trade do tend to increase overall wealth. But not everybody wins.

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Thanks to the following Patrons for their generous monthly contributions that help keep Crash Course free for everyone forever:

Mark, Eric Kitchen, Jessica Wode, Jeffrey Thompson, Steve Marshall, Moritz Schmidt, Robert Kunz, Tim Curwick, Jason A Saslow, SR Foxley, Elliot Beter, Jacob Ash, Christian, Jan Schmid, Jirat, Christy Huddleston, Daniel Baulig, Chris Peters, Anna-Ester Volozh, Ian Dundore, Caleb Weeks

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In which John Green teaches you about the presidency of Andrew Jackson So how did a president with astoundingly bad fiscal policies end up on the $20 bill? That's a question we can't answer, but we can tell you how Jackson got to be president, and how he changed the country when he got the job. Jackson's election was more democratic than any previous presidential election. More people were able to vote, and they picked a doozie. Jackson was a well-known war hero, and he was elected over his longtime political enemy, John Quincy Adams. Once Jackson was in office, he did more to expand executive power than any of the previous occupants of the White House. He used armed troops to collect taxes, refused to enforce legislation and supreme court legislation, and hired and fired his staff based on support in elections. He was also the first president to regularly wield the presidential veto as a political tool. Was he a good president? Watch this video and draw your own conclusions. Support CrashCourse on Patreon: https://www.patreon.com/crashcourse

Hey teachers and students - Check out CommonLit's free collection of reading passages and curriculum resources to learn more about the events of this episode. On of Andrew Jackson's most lasting and memorable policies was that of Indian removal: https://www.commonlit.org/text....s/andrew-jackson-s-s
Jackson’s promotion of this cause led to the infamous Trail of Tears: https://www.commonlit.org/text....s/excerpt-from-trail