Evidence of Evolution 5- Homologous structures
– So the fossil recordalso gives us– and simply living critters, there’s tons of way thatwe’re going to seem at this, however a different piece of evidencethat speciation has– that we’re relatedto each different, that we’re relatedto different critters, and the extra associated we arethe extra similarities we have– more evidence of that’s this inspiration calledhomologous structures. And what does that do for you? Does that make you go hello, i know what homologousstructures are given that i like homologouschromosomes and homologous chromosomes arevery an identical to each other? And so you may expecthomologous constructions to be very similarto each different, and in fact that they’re.Check out these fossils. This is goingto blow your mind. Here is a cladogram. You might have noticeable somethinglike this earlier than. You’ll find who’s mostclosely concerning whom. We now have a ray-finned fishwhich is sort of a trout. That is not a trout. That appears like a tunaor some thing like that. Ray-finned fish have fins. They shouldn’t have palms. They’ve acquired– what are they? Little rays, which maybe whythey’re called ray-finned fish when you consider that they’ve gotall these rays that go out and let them swim. However they’re no longer fingers, and they do not need palms. But there’s a fish calledthe lungfish, and that– ok, it looks like we don’thave lungfish body materials, but these are fossils that theyhave determined. Look at this factor. The Eusthenopteron hasinside the fin– that is a fin– they have these bonesthat are homologous constructions to a residing tetrapodwhich has a humerus– that is a humerus– an ulna, and a radius to your forearm,your whole wrist bones, your metacarpals,and your phalanges.And that pattern– seem, here they are:your phalanges, your ulna, and your radiusand your humerus– one enormous bone, two long bones, a whole bunch of littleblobby bones, after which fingers. These guys have it: finger bones, blobby bones, two forearm bones,and an arm bone. Fingers, blobby bones,two forearm bones, and a humerus,one lengthy arm bone. And then look at this,even this man. Who is this man?That’s Tiktaalik. That’s the primary onethat came out of the water. In case you have this setup occurring, you’re now not goingto floppy-flap your fingers.You could walk on those matters. You have bought bones in thereto support these fins which is a steptoward having a limb. So you realize what I justsaid considering that I began going backwards for the reason that we variety ofhad to grasp what our anatomy is. Residing tetrapods are livingcritters which have 4 legs, and we’re includedin that despite the fact that we get up on two of them and usethe different two for hello now. So this right right here is actuallyevidence of macroevolution, of speciation. It can be proof of critters movingfrom the ocean and onto land. I believe i have a further visual.Right here is an extra visible. This one isall dwelling creatures, so these are residing tetrapods.The opposite one was fossilcreatures which is fairly cool. But this one, you’ll find thatthey’ve colour-coded the bones so to visualize whichones are homologous buildings. It is the same bone. It’s been fairly modifiedfor a different function. The structure has been relatively modified for a differentfunction. However look, gorilla, canine pound,looks just like us.A bat– appear at those longfingers, and this can be a wing, but these bones areall still in there, same pattern– long bone, two lengthy bones, plenty of blobbybones, and fingers. Fingers, blobby bones,two lengthy bones, and one long bone. And then here is a whale. That’s its bones within its fin.Wow, that’s powerful. We would appear at a fowl as well, and we’d see the exactsame identical sample due to the fact that it’s the exactsame equivalent sample.Now, homologousstructures point out relatedness. It’s really importantthat that works on your mind. If a structure is homologous, it suggests thatthese creatures are concerning each different. The bones are homologous. There may be one more kindof structure, and it is calledan analogous constitution. And let’s talkabout that one next..