Cladistics Part 2: Monophyly, Paraphyly, and Polyphyly 

The Law of Monophyly states that you can never grow out of your Ancestry, meaning that once an organism belongs to a clade, it always remains within that clade (& the specific criteria for that clade will always describe them). Humans are *Eukaryotes:* Organisms with cellular *DNA* contained within a *Nucleus* protected by a *Nuclear Envelope.* This characteristic evolved way back when our ancestors were still single-celled microbes (during the Proterozoic Eon, approximately 2.1 - 1.6 Billion years ago), but despite since having evolved into much more complex, multi-cellular lifeforms, we are still members of the Eukaryote Clade & always will be. ~⊚~ Anyone interested in Biology (especially Evolutionary Biology & Cladistics), I highly recommend that you watch *AronRa's* (Paleontologist) brilliant RU-vid Series: *_The Systematic Classification of Life._* Over the series, he follows through most of the *50+ Clades* in the Human / Homo Sapiens lineage (plus discussing the evolution of several other clades) all the way from the beginning (or as close as we can currently get) through to modern day. It's profoundly fascinating & utterly addicting. ; ) [ ru-vid.com/group/PLXJ4dsU0oGMLnubJLPuw0dzD0AvAHAotW ]

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Lol

Lmao

Lmaooo

Kunt will just ignore it, blatant lies make him way to much money for him to ever change his script.. aron ra done a whole series debunking kunts lies in the textbooks series but i think you've already seen it, your name looks familiar

Everything I learned about classification in the 1960s & 70s has been thrown out the window. I first realized this when I was 'corrected' several times by people much younger than me, who learned within the new system. It's weird for a former honors biology student to feel archaic. The obsolete man, so to speak.

@Sage I'm so glad nobody ever subjected me to creationism in school.

Check out aron ra the systematic classification of life.. it's well worth it.. in my opinion it's the best series on RU-vid (sorry professor Dave), I've seen it at least half a dozen times already and i intend watching it again at least a few more times.. it's about 50 10 minute videos and it's easy to understand in little bite size pieces

Plants are covered in the botany series, fungi in the mycology series, and bacteria in the microbiology series. This is the zoology series.

Mmm, whether or not a non-monophyletic group includes the most recent common ancestor of all included organisms is a good diagnostic trait distinguishing between paraphyly (includes MRCA) and polyphyly (does not include MRCA)

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Primitive 1. Of or pertaining to the beginning or origin, or to early times; original; primordial; primeval; first. 2. Of or pertaining to a former time; old-fashioned; characterized by simplicity. 3. Original; primary; radical; not derived.

@@DS127 you seem to have missed the point.

@@QT5656 Primitive isn't misleading. It has a technical definition that's the antonym of derived.

​@@DS127 You *have* missed the point. Primitive is indeed misleading in the context of this video which is discussing taxa in the context of trees and cladograms. As Professor Dave explains at 4:40. ALL animals alive today have been evolving for the same length of time. There are no living animals that represent ancestors. Therefore, it is misleading to refer to any living (extant) taxa as more primitive than another. Individual anatomical traits may be described as primitive relative to other traits and it is possible that some taxa have more traits inferred to be primitive that others. However, *all* living animals are a mixture of primitive and derived anatomical traits. Referring to living taxon as primitive is misleading and leads to circular reasoning when evaluating their anatomical traits: that all or most of their traits are primitive. There are many examples when such assumptions were made and further research showed that these assumptions were incorrect.

@@QT5656 You are correct. I misread you. I blame lack of sleep, skimming your comment, and carelessness. I was talking about possible meanings of the word itself. One could argue that referring to living taxa as basal/primitive is not just misleading, but self contradictory.

@Sage Related means they share a common ancestor and have similar features, but also that they are distinct in some ways as well. The concept of clades tells us that they share a common ancestor with each other that the don't share with any outgroup. The concept of grades tells us that birds have lost certain reptilian traits found in snakes, lizards, turtles and crocodiles and gained special avian traits like wings, beaks and feathers. I guess the trend now is to just include birds as another order of Reptiles rather than having their own status as a class. I can live with that.

Evolution involves both ancestral traits shared by closely related clades and derived traits that are found in descendants. That makes different taxa similar in some ways but different in other ways. It seems to me that clades emphasize common ancestry while evolutionary grades focus on derived traits. Regardless of how we classify organisms, I like to look at both of these views.

That's mythology, this is reality.

How'd your test go?