Community Ecology II: Predators - Crash Course Ecology #5

Hank gets to the more violent part of community ecology by describing predation and the many ways prey organisms have developed to avoid it.
TABLE OF CONTENTS
Herbivory and Parasitism 1:43
Predatory Adaptation 3:39
Cryptic Coloration 4:25
Mullerian Mimicry 5:43
Batesian Mimicry 6:38
Resources:
• Video
• Zebra Vs. Lion
www.nature.com/...
necsi.edu/proje...
animals.howstuf...
www.animalport....
largestfastests...
news.nationalge...
www.nytimes.com...
lancaster.unl.e...
www.talktalk.co...
www.waza.org/en...
people.wku.edu/...
www.strangescie...
science.howstuf...
www.reptilechan...
users.rcn.com/j...
Thanks to the Boone and Crockett Club for letting us film the introduction to this video in their headquarters here in Missoula: www.boone-crock...
Crash Course is on Patreon! You can support us directly by signing up at / crashcourse
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[@IHeartViHart]

Grass has a great defence. Its leaves (the above ground part) can get eaten, burnt, trampled or whatnot, but the important part of the plant remains perfectly viable and it simply grows new leaves. Grass is very hard to kill without poisoning the soil it grows in.

[@nataliacostard3525]

hey guys, not sure if that kind of request is common around here, but as i've never seen any i must say your channel is probably the best educational one, and as all videos are pretty well made and the subjects you approach absurdly understandable i was wondering if there is any possibility of making a series of videos over fine arts and/or astronomy. it would be awesome! thank you though for all the videos you've already uploaded, they are great, really

[@dreamjobs7113]

Hi

[@deadmansvision5926]

@@dreamjobs7113 Hi

[@dreamjobs7113]

Hody

[@karidoyle4828]

Hi Hank, my high school students here in SF introduced me to your work about a year ago and I have been using your material ever since. Keep it up! You are highly appreciated out here at The Bay School!

[@LeonardLew]

Thank you thank you thank you for making this episode more varied in it's shots and stepping up the cinematography. It feels so much more engaging. Awesome episode, very informative.

[@LovingDeWorld]

Crash Course actually makes me feel passionate about Ecology, which is a feat I once thought impossible. Thank you.

[@SravyaBalasa]

GOD BLESS YOU'RE TEACHING ME EVERYTHING MY AP BIO TEACHER DIDN'T :) i'm not even cramming and i'm really enjoying learning this THANK YOU

[@ashlynnundlall]

This is biology. Their is no god! Only evolution and natural selection.

[@tensequel7818]

actually, this is ecology...

[@charlenegalvez100]

Star Lord Yea but ecology is part of biology

[@davescave7267]

I am using this series and the Biology one to study for my finals this week :) Enjoying the format and information greatly. Thanks!

[@shanbotable]

I like this guy, but I feel like he's talking and 1.5 speed

[@samrader3361]

adventureish You can change the playback speed!

[@TashaaKay]

"...eaten ourselves into extinction" lmao Hank has the best quotes

[@earlgreytempest]

Thank you for getting across the idea that the natural world is not a static, balanced system, one that will instantly fall apart if the balance is disrupted, but a constantly changing and transforming web of interactions between species, their environment, and of course the effect of human activities. This message comes through in all your ecology videos and I think it will help people have a more complex understanding of the natural world. DFTBA!

[@xanderx3]

Wouldn't perfectly mimicking the poisonous butterfly cause problems for the non poisonous butterfly? As distinguishing between their own species and the one of the poisonous butterflies might become a bit on an issue during mating season as they would both look the same. Though with the aid of scents and other factors the animals could potentially look the same but there would then be the issue that they could be tracked via their scent. Also I would like to say that I love watching your lectures they have helped me allot with my studies over the past couple of years, they are really insightful and are a great builder to help foundation my studies. Thanks to all of you

[@xanderx3]

Jeremiah Blondin Thank you for messaging back, not many people do with an actual answer. That was really interesting I never even considered that butterflies see in a different so they'd be able to tell the difference whilst completely fooling the camera eye. Thanks

[@JacobWP]

I swear, you mustve been in my ecology lecture yesterday... You and my professor talked about literally the same things!

[@reaflor91]

I honestly thought that when he got to the Snowshoe Hares, Hank would say that they look like snowshoes.

[@cassinipanini]

I never realized how nice Hank's eyebrows are. Thanks, angles!

[@harrykim9758]

To those 51 people who disliked this video I have you know that Crash Course has saved my grade more times then I've opened my computer. So, don't hate on them

[@stephyrodas6843]

I love these videos As an IB students it helps me to remember certain info . THANK YOU!!!

[@jonasbigplanet]

The variations will mainly focus on traits that won't affect the mimicry however, if we are talking about the mimic. They would use chemical receptors to recognise mates, not differences that predators would notice. So if trying to copy another species and both have predators that use smell to detect them, they would use different mechanisms to recognise each other. The mimicked organism (if batesian) will be selected to be different anyway in order to minimise the dilution.

[@kimberlynguyen124]

Can you replace my science teacher?

[@jbowman6981]

faithopeace Honestly I was just thinking the same thing! He's so great

[@tarantiquentino9538]

+faithopeace Can I replace your face?

[@TabinaKamal]

Ikr. He's also cute

[@ravi9157]

waaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

[@ravi9157]

noooo he aint

[@fish763456]

You guys should make an optional test you can take every 5-10 episodes or so, then make a bigger test at the 20 episode mark and another at the 40. I think this could be helpful because I usually remember most things I hear but once I learn I was wrong I hardly ever forget that fact.

[@DJMJRyder]

Loving the Ecology series. Looking forward to the next instalment DFTBA

[@lifewsteve]

I'd like to go to a museum with Hank, he'd explain everything from start to finish.

[@Grasmel]

From what I know they have two main defences: Growing from the bottom and fast reproduction. Growing from the bottom means that most of a grass straw can get eaten, but as long as the bottom and roots are left it can regrow. Spreading its seeds a lot and also spreading via roots means, it won't matter much if some grass gets eaten, there is plenty left. Also, getting shat upon isn't really a disadvantage for a plant.

[@1901180108]

My thinking was along the same lines, but you articulated that better than I ever could. I do believe, though, that mimic animals don't need to look exactly like harmful species anyway. With enough harmful species that have a particular trait, like a color combination, that color combination or other common trait is all that's needed to make the association. Most other traits are irrelevant as far as the predators are concerned.

[@Altrantis]

I think the reason mimics rarelly perfectly mimic their object of mimiquery is because they themselves need to know if it's the actualy dangerous species or one of their own species with which they can mate, rather than be killed by.

[@rthecrook]

I have a university final on this in about a week. THANK YOU HANK. Ecology isn't my jam, but this will help me study.

[@depressioncherries]

I watched this video before an exam that I did yesterday. I GOT A*! Thanks scishow!

[@theoneilovemost]

9:00 to determine the accuracy of the mimic you'd have to look at the behavior in question and the process by which the organism developed set behavior.

[@Remiem08]

About 6 years ago, I had the same opinion. I'd been told that because mutations could only alter and/or delete genetic markers that getting new "information" from old DNA was impossible. Turns out, DNA replication does use what it already had, but it's imprecise, so while it can alter or subtract base pairs, it can also add them. This addition is partially responsible for the accumulation of new and different "strands" of DNA from our ancestors to us.

[@peregrination3643]

Looks like the title is plural, "The Naturalist on the River Amazons," but thanks for contributing to my to-read list. I love historical science books, especially the era of naturalist explorers.

[@MyMurphysLaw]

I wish there was something more than a subscription I could give this series!

[@deserpuppy]

NOOOOO I can't believe succession is next weeeeeeek :( My ecology final is on Friday and that would have been so awesome to watch before it! The videos are really helpful though, thank you for posting them! :) Sometimes you just need things to be explained in different ways, like a niche as a job, to get it :)

[@DanJinMusic]

hank green and co. saved my life. perfect for SAT II Biology. can't thank them enough, so i'll give them money by watching their videos more.

[@DeluxeFlame]

Hey Hank Thanks for Being Awesome.

[@chanliestchan]

explanation of competition to see why Darwin's theory actually does a good job of explaining evolution and speciation. Understanding more than just the competition interactions explained in Darwin's theory, like inheritance and variation as added later to our understanding of evolution, might help this user understand Natural Selection, the process of evolution, and speciation.

[@liamoleary9957]

@MrBurningDonkies it's not really that much different to the Peppered Moth example mentioned in one of the earlier videos. Because animals use bright, bold colours to disclose that they are toxic then potential predators will not eat them and they will avoid them - allowing the bright coloured ones to survive and reproduce more effectively. Therefore, some similar species will seek to mimic this perk (poisonous or not) as it increases the chances of survival and reproduction for the species.

[@mynameisdanielrobles]

I have always thought this but never posted it. Your should make longer videos

[@humor86]

grass have loads of different defenses. Some species grow really short, which makes them harder to eat. Some contains a lot of silicon which makes them hard to chew. Some grass tastes bad. But most of them just grow a lot, and because of that they doesn't take much damage when parts of it gets eaten.

[@chanliestchan]

Ah yes good point. I guess I didn't clarify. I was not agreeing with usurp but rather trying to explain that there was more to it: Darwin's ideas were indeed right on most accounts but I failed to clarify that though Darwin explained the competition part of the theory well, we didn't gain clarity on the inheritance and variation parts of the theory until a bit after Darwin's time, although he did indeed include them in his idea. So I meant that it takes more understanding that merely the

[@Coop838]

I love how Hank always talks about how temporary humans are. How we will be extinct. It really puts things into perspective.

[@sharonchase4802]

One day this man will read from the middle of the book, instead of the first five pages.

[@Derperfier]

Sharon Chase in a 10 page book?

[@sudeepjoseph69]

@@Derperfier Dumbo kinda dinka chimpssuy

[@kathrynbrown584]

Can you please make a video about Epilepsy??????? Also really love these videos!!!!!!!

[@Emilytheawesome131]

When you're done with ecology can you PLEASE do crash course chemistry!?

[@sjthompson4]

Dude, love this show and I love that it's based in Missoula (which is where I'm currently living). I was wondering where the museum that the opening scene is shot in?

[@bleerrgghhhh]

if you click 9:23 over and over again it sound really amusing. 'PRDASION'

[@aidanm.1683]

What about ATANGLERFISH

[@kunisha4280]

Lol 😂🤣🤣🤣🤣 ur right

[@otmrs]

Because Hank has a week to put out one ten-minute video. A teacher must provide hours of lessons every day. It comes down to the ability to spend time preparing and perfecting.

[@ZoggFromBetelgeuse]

A question: Is the natural yellow-and-black color code the reasons why you earthlings often use yellow and black stripes as warning pattern for, e.g., construction machines ?

[@MrBurningDonkies]

I do not understand mimics...the question lies in HOW. How does one species mimic another? would that not imply a decision? What steps of evolution made an animal change to mimic another, especially in color. Perhaps i'm looking at this backwards and species who were not poisonous simply branched off from species that are and thus look alike. I'm going to have to do more research, the HOW is bugging me.

[@cookiejabba6588]

I just wrote my exam on exactly this topic yesterday. this information would have probably helpt a lot. Still awesome

[@thejerrymobile]

Whenever considering prey species, I often wonder why there aren't any mammals that have adapted a green coloration... I know, more grass on the planet is shades of brown than shades of green, and apparently brown is a much easier color for a mammal to be, but I'm surprised there aren't any notable exceptions...

[@NoAnchorTV]

I really appreciate what you do!

[@Teaj383]

Okay, this has nothing to do with the episode, but my ad before the video was a song about TFioS. That made my day :D

[@aphrog649]

Why don't the ecology videos use Thought Bubble?

[@TheWolfgangGrimmer]

+Lily R The biology ones don't either. I guess Hank just did things very differently from John early on for whatever reason.

[@toxiPsychotic]

I guess last just has two meanings; it can either mean the opposite of first, or the opposite of next. Usually you should be able to tell which by context. (for example, if you see a next and last button, you can assume that the last button is being used to mean the opposite of next.) Honestly, i think most people don't actually understand what the difference between sex and gender is. The average person probably thinks they mean the same thing. The same goes for people who make surveys.

[@otmrs]

Crashcouse does 1 Hank and 1 John video per week, I haven't noticed a slowing of uploads.

[@Aldowyn]

My favorite example of Batesian mimicry: The milk snake copying the coral snake, mostly due to this cautionary rhyme: 'Red touch yellow, kill a fellow. Red touch black, venom lack'. (Sorry milk snakes!) (Interestingly, the wikipedia page never mentions a version of this with the phrase 'venom lack', instead being seemingly fixated on a fellow named Jack.)

[@Titamiva]

06:19 Its Fritz Müller and Müllerian mimicry. You missed the umlaut. Otherwise: a great show!

[@elwynbrooks]

That's a great hypothesis! What do you think the experimental design to test that should be? :)

[@Simplebeing2435]

This is a lot better than actually reading the textbook. :)

[@TadaGanIarracht]

Has anyone seen the wasp marked mantis fly!?? Such a BADASS!! Half wasp, half mantis, half fly. So cool it doesn't even add up right.

[@dplocksmith91]

I propose that Batesian/Muulerian mimicry is imperfect for a simple reason: sympatric species, which share the same habitat with different species that may be of the same genera, need to be able to know who to mate with so that they don't interbreed and cause infertility in their offspring. Slight variations in the mimicry will act as reproductive isolators, allowing individuals to recognize others of their own species.

[@bowerbjo]

To get overly technical, the fastest animal in North America (and as far as I know, the world) is the Peregrine Falcon, which can reach speeds well over 200km/h, which most certainly bests the Pronghorn's top speed of about 90km/h.

[@ruolbu]

Well the common grass type (is there such a thing?) might not have much of a defense. But other plants like to be all poisony and taste bad. Also grass just kinda grows frickin' everywhere so most of the grass probably does not care if some part gets trampled into the ground. Getting eaten might not be that bad either. Maybe the plant does not always die or beeing shat out some place else could help spread the plant to other regions.

[@HokkaidoMaster]

Probably not the greatest weapon of all, but it's definitely our greatest weapon. But yeah, our social lifestyles and our ability to reason through situations and use tools to accommodate those situations are our greatest strengths.

[@angusrc]

bison eating grass isn't really considered predation because the grass isn't killed by the interaction. Herbivory refers to the mutilation or damage of an organism by another for food, without death though.

[@BeastOfTraal]

You should do an episode on Symbiosis

[@jeaniebaby001]

watching this in full screen is awesome. i'll never watch scishow any other way again.

[@65536ot]

because getting eaten or walked on doesn't kill the grass since grass can survive having a part of it removed, that makes it harder to kill , you know when you mown the lawn after a while the grass grows back, that's because you didn't kill the grass you just cut a part of it off

[@olejorgensen1964]

Hi. Love the shows. I have a question for the audience here. English is not my first language - doh! So I wonder - in the Crash Course series the episodes can be selected by choosing "Next" or "Last" - I find Last to be a strange choice - why not Previous ? It's not selecting the very last episode. It's like on English questionnaires when asked about whether you are male or female. Often they as about you're "sex" - Why not gender?? Anyhow - I love the shows Sheers from Denmark

[@LynneSkysong]

It was set to private for the first couple minutes, so we couldn't watch it until now. Or at least that's was the message I got when I tried.

[@aquara0501]

Are there any books you would recommend for learning more about Ecology? I've heard that Darwin's On the Origin of Species is quite a dry read so I was hoping for something a bit more engaging. Also, I know that Wallace and Darwin corresponded but what about Darwin and Bates/Muller?

[@gearmonkey]

I've always assume that the only rule to which there is no exeception is the always an exception rule. But perhaps that is not the case.

[@ThomasstevenSlater]

We took the claws and teeth that we thought would be useful and then made them deadlier/made our own. Domesticating dogs got us super hearing smell without having to use up the brain space. Also fire is very very useful.

[@Kram1032]

I would *never* get you started on Anglerfish. Especially because I'd rather have you get started on Hanklerfish. Tell us all about the Ecosystem, Hanklerfish usually live in :D

[@Tamerleen]

In the video he says that co-evolution has been going on since the Cambrian explosion. Didn´t it go on earlier as well?

[@Tenocticatl]

Being shat upon is actually useful for grass. Being eaten isn't, but it spreads through its root system so that it's not a problem if some blades are destroyed.

[@mustafakazi4145]

great videos

[@SomeExtraNotes]

There are some plants hat produce seeds that won't germinate unless they have been digested and pooped out. Could that be considered a form of defense?

[@AlexiLeclerc]

it's fine, i was just trying to avoid any misunderstandings among others that may have been looking through comments

[@Entropy114]

Okay, so as I'm watching this, I notice an especially fat robin pecking at the dirt for an extended duration, obviously eating a cache of bugs she (probably she) found. I then notice the dirt moving underneath the bird... Upon further inspection, there appears to be a mole in my yard burrowing its way towards my garden, and is scaring up subterranean bugs towards the surface, where they are promptly gobbled up by the robin. Just thought I'd share, considering its a video about predation.

[@xtxylophone]

Could the non perfect mimicry be so that others of the same species have a slight way to differentiate between their potential mates and the other random toxic butterfly?

[@StygianBeach]

I would assume non perfect mimicry would exist because perfect mimicry is just not necessary. If I see red and blue flashing lights I am going to be cautious regardless of the shape of the source.

[@rico1463]

Got pretty dark when you were talking about human extinction and being on display...

[@Mattteus]

"Make love, not war" - Grass

[@EdenNov]

"Don't even get me started on the Anglerfish" Oh Hank...

[@INStudiosMovies]

yaaa!!!!!!! never seen one of hanks videos before thousands of others

[@sogghartha]

It would mean there is going to be some new intelligent species with an advanced culture. Sounds pretty good to me. Much better than to be forgotten completely.

[@yousof77]

Please do something about radiation! It would be a great help!

[@chanliestchan]

To illustrate, to live 120 million seconds would be to live nearly 4 years long. To live 1 billion seconds would be to live about 31 and a half years. So there's a comparison, but I'm not sure why this doesn't support evolutionary theory very well? That's a lot of base pairs but it's a minuscule amount compared to a genome, so this should technically illustrate that it only takes *enough* genetic change in order to speciate.

[@dirk0389]

Thank you for differentiating between bees and wasps. I hate having to correct people on that.

[@MeganMcken]

hanks hair looks very lovely today; very fluffy.

[@ymmijx6061]

actually in a way they aren't totally they're energy comes from a combo of solar (plant matter) and geothermal (pressure and heat) which together make them a far more useful fuel source than wood or any resource really

[@Arpin_Lusene]

Those are really good taxidermy

[@malloryperry7740]

Can you explain to me directly as to what Mullerian Mimicry and Batsian Mimicry is? I didn't really understand the defenitions.

[@zacharyivanhawkins251]

5:22 awesome example: Datura

[@daydodog]

I think they would eventually obtain near perfect mimicry, however, I think they generally reach a state of "close enough"

[@GigaBoost]

Where do hard shells or spikes (turtle, porcupine) fit in to this list?

[@tigerwhoocametotea]

i would quite like heat sensing organs.. do i have to become cold blooded first though?

[@pacogoatboy]

Depends on the grass, but it is almost inedible and contains very little food value. It takes a highly developed stomach to be able to get anything out of it, and even then it requires huge amounts of grass digested very slowly. Add to this the fact that many grasses are toxic and there ya go - defenses. It also resists damage caused by being walked on and does better when things poop on it (fertilizer.) All hail our grassy overlords!

[@AppleCheese12345678]

Grass also doesnt die when cut in half, or walked on. And being shat on is actually in the grasses favour.

[@Vaurion]

Not to mention, that's not speed under it's own power, that's speed in a dive.