Cladistics Part 1: Constructing Cladograms

Before we dive into learning about all the different kinds of animals, we have a little bit of work to do. How do we describe the relationships between animals? How does phylogeny work? We have to learn about cladistics, which means we have to learn how to build cladograms. What are those? Let's find out!
Script by Ryan Helcoski
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[@arethysa]

just dropping by to say thank you for this series! i've been looking to study these topics independently as a hobby but i was always overwhelmed by the mountains of information i had to sift through. being guided through the basics has been the most helpful thing! many cheers, professor!

[@liser5566]

I´m studying biology and it´s a good way to explain cladograms and phylogenetics :) Also it´s so important to diferenciate between homologous characters and analogous characters, since analogous characters can lead to false phylogenetic hypotheses

[@PunmasterSTP]

I'm just curious; how are your studies going?

[@The_Jovian]

Are cladograms possible to make with certainty if you are unaware of which similarities are homologous and which are analogous?

[@mrdraco3758]

​@@The_Jovian yep, the best way to check if a feature or trait is homologous or analogous you can use genetics and the fossil record.

[@absw6129]

I have learned more from this guy than I ever did in school.

[@AestheticallyViolet]

Thank you so much! We have an evolution test tomorrow, and I am feeling confident now thanks to you!

[@S1nwar]

i bet this will spiral out of control and end up with a 1 hour crocoduck debunking because creationists reacted to this video like flatearthers to the other one.

[@danbrisson432]

I agree, very informative for those scientifically minded but for some it will be misrepresent by the “ Whack and Atheist” group or AIG news even though it has nothing to do with religious theology. This is taught even in Mainstream Colleges like Georgetown, (Catholic ), Syracuse ( Protestant) to name a few.

[@iscribbleovermywork8009]

I have found my calling, ZOOLOGY IS AWESOME I LOVE LIFE I'm 14 and just found a new passion, I want to become a zoologist or anything that involves zoology. Prof dave, you are a great teacher and I love the way you explain things. Well, it's in your channel name, after all. Andddd now I fear growing up and having to make decisions. Eugh. Eh. Hm. nvm i'm alright now back to being.

[@l_wnm]

Wow! Haven’t found good explanations in my native language an decided to switch over to English - so will explained, thank you!

[@marccolten9801]

Clades are relatively new to me so I welcome this video. Still I am confused. Clades do not seem to be diagnostic but illustrative of decisions you have already made. You can reject similarities because you already know to reject them, like flight. I remember a statement from another KZbinr’s video that an animal is “... carnivorous, but not a carnivore”. Or that a certain creature belongs in a certain group despite not having a defined characteristic. I’m not sure I see what good they are if you can include or exclude a creature at will. But I’ll keep watching. Thanks.

[@Angelmou]

I assume the difference between homology and homoplasy will be explained later in detail.

[@mikefochtman7164]

But what about independently evolved characteristics?!?!?! (watches rest of video) Oh... um... yes, I see. Never mind.... :)

[@karunootvlogs]

A lot of thanks to you professor

[@Sven-Wagner]

Nice and very good explained, especially for non-scientists like me 😎👍

[@glennpearson9348]

Great presentation on cladograms, Professor Dave. Love this stuff!

[@nicholasbailey6622]

Starting around 8:30 you mention that traits like flight or warm-bloodedness would be bad traits to choose for cladistic grouping as they are both examples of convergent evolution, not homology. While that's demonstrably true of those traits I feel like the way it's phrased almost implies we should choose traits that we know will give us an answer we pre-determined. It seems to me that really what you'd want to do is have as many traits as possible so that you can separate out homologous and analogous characters.

[@MisterWillow]

Yes, this point deserves more explaining indeed. It seems like it is a random pick now.

[@benjamindover5676]

Flashback to 8th grade. Sad that education failed these people.

[@ProfessorDaveExplains]

Who?

[@tiedeman39]

@@ProfessorDaveExplains Flat Earthers and young earth creationists, most likely

[@naveenchand8402]

Please upload more videos on Organic synthesis challenges and mechanism challenges. They really are helping alot.

[@PunmasterSTP]

Oh yeah that'd be awesome! I like videos breaking down individual reactions and mechanisms, but I think it's the synthesis (and retrosynthesis) questions that really tie everything together and lock in concepts.

[@nickconnel5562]

Thank you so much biology Jesus i got an A cuz of this

[@SCIPROlearning]

You made it so simple 👍👍

[@SirAlecYT]

This guy just explained my full Cladograms unit in Biology that ive been learning in school in less than 11 minutes. Thanks Dave

[@StudyHoursV2]

Watched: claditics common characteristics, outgroup furthest out, a point is a certain part in its history. synamporhy,s a characteristic or trait that is shared by two or more taxa (groups of organisms) and is inherited from their most recent common ancestor. Convergent evolution when animals develop similar traits.

[@manuellaconde9562]

thanks

[@szxnv]

appreciate you dave!

[@rickschofield3131]

Excellent video exemplifying the absurdity of the term more evolved

[@lokeshjoshi5672]

🤩🤩🤩🤩 wow

[@eldersprig]

Don't house cats have quantum effects? Or this the wrong playlist?

[@cryptocoinkiwi8272]

They can teleport if you sneak up behind them.

[@swoyaman4969]

Hey dave what happend to the debunk series that was too fun do sadhguru next!

[@ProfessorDaveExplains]

I will get to some more debunks eventually, I'm just taking a couple months to get ahead on my academic content.

[@swoyaman4969]

@@ProfessorDaveExplains sweet

[@elbee2324]

I suspect that humans were deliberately chosen as not the final point of the second main example, to clearly show that having humans above all or the end point is not the point of this system. Something tells me that might be a common misconception for some. :-\

[@DeepakTrader]

Love from India🇮🇳

[@rickschofield3131]

I would love to see a video how to incorporate convergent evolution in this type of system how would you incorporate a divergence and a convergence into this system as it would not account for all previous divergences being present on 2 converged characteristics. Would they have to be kept separate but the same?

[@liser5566]

Convergence can never be used to carry out a phylogenetic study since it is given by analogous characters, which are different in convergent groups Only derived homologous characters can be taken into account to make a cladogram

[@unwono]

This is very cool 👍 I've always liked these videos thanks for making them

[@amyjojones1005]

Teaching a gizmo to 8th grade- this was perfect, thank you

[@blazikenafonso2758]

Very informative video! Thank you!

[@RamiK101]

This was brilliant! Thank you

[@GainesMusic]

Lots of funny words

[@apeearth6335]

YES! YES! YES!!!!

[@JustinBrown-wc1ph]

thank you, my lab made it super hard to understand

[@AkselWaage]

Really glad you're covering cladistics!

[@PunmasterSTP]

Would you also say that you are..."clad"? 😎

[@PunmasterSTP]

Cladograms? More like "Glad-ograms", because I'm really happy that you're covering these topics!

[@complicated_smurf7476]

im joining the professor dave cult i love these videos so much!!!! LOVE U DAVE

[@user-yr5yl6zt5l]

I love your playlists

[@nighthamato]

Thank you so much for this video. This made me understant instantly!!

[@vincentheartland2088]

While the clades cannot indicate chronology in the sense of an amount of time in absolute units nor do they imply a causal relationship, the phylogenetic tree of life must indicate them as branching in the order of their appearance, right? It works by assessing when that trait first appeared in a given lineage thereby separating that lineage from its parent group, right?

[@brittanyjacobson5199]

Thank you, this is a topic that I love. Your explanation is very good.

[@jamiegallier2106]

❤❤❤

[@andreikleinerumpon3506]

Hi classmates

[@cos_meme8858]

If i ace this test your getting one sub.

[@aditidharwadkar1749]

Thanks professor Dave😊

[@CrackyCartoons]

I fucking love you

[@ReetTaj-e9y]

Great....🎉

[@SV42165]

Hair like Reńe Descartes.

[@StudyFocus-np2sf]

Thank you😊

[@Dailylisten72]

i will cry from this course

[@prernakaushal3211]

Nice explanation 😄

[@Iwatoda_Dorm]

5:47 7:20

[@Iamtheskidoostig]

Is Cladistics replacing Taxonomy? I feel like I don't know enough about either to answer my own question.

[@secularidiot9052]

Taxonomy is a hierarchal classification system while cladistics is a conceptual classification system. Taxonomy covers how a group of organisms has something in common while cladistics focuses on how individual animals have something in common. Taxonomy covers all organisms while cladistics hones in on animals and plants. Taxonomy is broad, cladistics is specific. Neither one replaces the other.

[@Iamtheskidoostig]

@secularidiot9052 much appreciated!

[@Dr.IanPlect]

@@secularidiot9052 That's a vague, inaccurate comparison and representation of each. As I've now told him, KONG should disregard your comment altogether.

[@Dr.IanPlect]

@@Iamtheskidoostig That reply was a vague, inaccurate comparison and representation of each. You should disregard that comment altogether.

[@secularidiot9052]

@@Dr.IanPlect Well, it was not meant to be a specific comparison. It was just supposed to be a rudimentary description and explanation on why one doesn't replace the other. If you believe that you can provide a better one, then be my guest. If you do have a doctorate in this field, then you would be far better at explaining this than I would.

[@scratchoriginalsdh]

I need to build a cladogram using primitive and derived characteristics, abcdefgh and ABCDEFGH, respectively. Of course the letters are mixed for each of 6 mystery creatures (1,2,3,4,5,6). The example cladogram starts the bottom branch with a capital "A", so this has me quite confused. Shouldn't each new branch show the next trait as a lowercase? I wish they were just giving physical characteristics as you have done.

[@Dr.IanPlect]

Do you want to go through this?

[@scratchoriginalsdh]

@@Dr.IanPlect thank you, I appreciate the offer, but class is long over and done with. I actually survived the question, and ended up with an overall 86 in the course -- not my best showing.

[@Dr.IanPlect]

@@scratchoriginalsdh No problem, 86 what? %? If so, !!!

[@scratchoriginalsdh]

@@Dr.IanPlect yes, that was a percentage. I believe forensic analyses of the human pelvis is what did me in, in that course. 🤣 I am taking online classes and I believe a hands-on experience would have made all the difference. (My in-person anthropology courses had me averaging a 3.9 GPA, so any number under 90 is hard to swallow).

[@Dr.IanPlect]

@@scratchoriginalsdh High self-standards! I'm from the UK so I had to look up where 3.9 puts you on the scale, _highly_ ! By the way, I simply have to get this bit resolved; "The example cladogram starts the bottom branch with a capital "A", so this has me quite confused. Shouldn't each new branch show the next trait as a lowercase? I wish they were just giving physical characteristics as you have done." For easy reference throughout my queries, I'm using the cladogram in this vid 0:58 - are you referring to (what you likely _now_ know to be) the root? In other words, the bottom piece of line pointing toward the o in cladograms... - or do you _actually_ mean where the lizard is? (bear in mind, your test cladogram was likely rotated 90 degrees clockwise based upon your wording 'starts the bottom branch'. Or otherwise, where, in regard to the vid cladogram was that A?

[@joanne_byun]

7:30

[@tfdinformation7534]

This is worst then math

[@Dr.IanPlect]

Your priority is grammar.

[@tfdinformation7534]

@@Dr.IanPlect what do you mean?

[@Dr.IanPlect]

@@tfdinformation7534 ffs! Read your comment...now mine!

[@tfdinformation7534]

@@Dr.IanPlect 🌚🌝 how can i understand Greek language or latin , it's stupid to use it , it just make things worst , why don't they invent a new language and teaches for us instead of this mess

[@Dr.IanPlect]

@@tfdinformation7534 Nil to do with Greek or Latin! It's YOUR comment!

[@hollikistvanfodrasza6937]

Dr. Kent Hovind dislikes this.

[@bighairyviking387]

I think you give that charlatan to much respect by referring to him as a doctor, considering his degree is a fake that he bought.

[@rickrhay]

Dave, how are you still pronouncing it 'spee-shees'? It's "species," like "specific." We don't say "spe-shific" so we don't say "spee-shees."

[@ProfessorDaveExplains]

That's not how English phonetics works. I'm saying it correctly.

[@rheiagreenland4714]

Both 'speeshees' and 'speesees' are valid and common ways of p pronouncing it

[@rickrhay]

@@rheiagreenland4714 Amongst us biologists, it's something of a shibboleth, to tell the difference between fellow scientists and media presenters.

[@rheiagreenland4714]

@@rickrhay i think if you're determining expertise or scientifc integrity based on minor pronunciation differences in already ambiguous words you're doing it wrong

[@rickrhay]

@@rheiagreenland4714 I don't know about that. Specificity matters in science. But hey, feel free to pronounce it any way you want.

[@handsome.mr.papa.________2711]

Earht is flat

[@ProfessorDaveExplains]

You're a little lost, sweetie.