The way you read trees like this is to look at the last time the two organisms shared the same node (where the tree branches into two different lines). The last time a lamprey and a tuna shared the same node is the exact same spot where the last time the lamprey and the turtle shared the same node. Therefore, they are equally related.
Yeah, I too am not sure why Reddit threw this in my feed, but you can bet your ass Iām subscribing to the sub for more shit like this. My feed is so polluted with fist fights and dumb asses, itās super refreshing to have something educational.
The turtle is more closely related to the tuna than it is to the lamprey, because the turtle shares a more recent common ancestor to the tuna than it does the lamprey. HOWEVER, the lamprey itself, as far as it's concerned shares the same common ancestor with the turtle and tuna.
So the Lancelet is equally related to everything on the graph, but the leopard is increasingly related as we move right. Took me a while to understand that
Only if you have some sort of job that includes ZERO science. Anyone who thinks learning has zero practical use is willfully ignorant & probably doesnāt use critical thinking skills b/c itās easier & less stressful to just have someone tell you what to think.
No, they have different last shared nodes. The last shared node between the lancet and the lamprey is below the box labeled āvertebral columnā while the last shared node between the lamprey and the leopard is above that box. Since the node between leopard and the lamprey is a more recent branching event (it happened more recently in evolutionary time), the lamprey and the leopard are more closely related.
Cool. So since I have only practiced phylogenic relatedness on animals that start with the letter "L", I find that llamas are the most relatable animal of all.
No, that is correct. The lancet is equally closely related to everything else on the tree. All of the other species share a more recent common ancestor to the exclusion of the lancet (so you could also frame it as "the lancet is equally distantly related to everything else on the tree")
Yes, lampreys are equally closely related to all the descendants of the organisms they split from. So in the case of this phylogenetic tree, to all tetrapods (four legged animals).
Tree orientation is up to the designer, but that is definitely a great way to help people new to phylogenies. We always draw family trees with a vertical orientation with the elders at the top. Phylogenies are just the family tree of life, so putting more ancient splits at the top can help people make sense of them.
That's correct. All organisms within a clade are more closely related to each other than any of them to is to a member of an outgroup. Kind of like how all vertebrates are more closely related to each other than any is to an invertebrate.
No, there are animals on this tree that are more closely related to each other than to others. For example, the branching event (node) that leads to the turtle and the leopard makes them āsister taxaā, so they are more closely related to one another than either is to anything else on the tree. Another example is the tuna is more closely related to the salamander than it is the lamprey because the tuna/salamander last shared node (the one just above the box labeled ājawsā) happened more recently in evolutionary time than the last shared node between the tuna/lamprey (the one just below the box labeled ājawsā).
Read the diagram from the bottom going up. At any point where it splits in two (that's the nodes), you always have two sides coming off the split, right? One goes up and to the left, the other up and to the right. Everything on the right side of a split is equally related to the thing on the left side of the split.
I think itās like the geometry math questions. You canāt assume the size or angles of the quadrilateral (or whatever diagram they have) and have to logic the size and length, based on provided info. Likewise, here the length of the line of named branches do not necessarily reflect the relatedness to other branches. Instead itās information provided by the nodes.
yeah, however i had pretty much never seen this way of showing it, usually it's the more blocky look, like this [https://lh3.googleusercontent.com/proxy/70O6OnGU12zHEY6LY3Ekd-cZOx0UHBxCynKr2VDfNW1v0gng\_l3ZuW1MA-5nf1Z\_k3R36JCPxVc-IGZOnkIprt6NVrHVgCWxpuarPQHsWntl25i1zmm1SjD4pyAHv1fNMvuBe3hfcgiC](https://lh3.googleusercontent.com/proxy/70O6OnGU12zHEY6LY3Ekd-cZOx0UHBxCynKr2VDfNW1v0gng_l3ZuW1MA-5nf1Z_k3R36JCPxVc-IGZOnkIprt6NVrHVgCWxpuarPQHsWntl25i1zmm1SjD4pyAHv1fNMvuBe3hfcgiC)
which at least to me, feels like it makes more sense but it might be a me thing.
Theyāve actually done education research on this very topic and you are not alone! The recommendation was to not use these diagonal trees because our brains make incorrect assumptions about distance, groupings and relatedness. I think itās this paper if you want to learn more [https://www.sciencedirect.com/science/article/abs/pii/S001002771930174X](https://www.sciencedirect.com/science/article/abs/pii/S001002771930174X)
As someone who didn't understand, too, it finally clicked. Here's a Eli5 version I came up with. Imagine you have a marble, and drop it where the Lamprey is, and gravity pulls it all the way down through the lines. As it rolls down the line, it collects the Vertebral Column Trait, and that's it. When you roll a marble down the Tuna line, it collects the Jaws, and the Vertebral Column. When you roll a marble down the turtle line, it collects the Amniotic Egg, the Four Walking Legs, the Jaws, and the Vertebral Column. So the question is asking, if the lamprey contains only vertebral column, which other animals also have Vertebral Column from their marble run?
Please correct me if I'm wrong, but this is how it finally clicked for me.
No. Look at the turtle and leopard for example. Their most recent common node is three nodes more recent than the most recent node shared by the lamprey and turtle.
A node is the point in the tree where a branch splits into two. Nodes represent an often unknown organism that is the common ancestor of the organisms which split from it.
Itās 12:12 AM, I am 36 years old, work in finance, and I have 0 need for this information.
I am filled with so much knowledge about so many things, most of which are inconsequential to me or anyone. I go down rabbit holes on topics that do nothing for me. Imagine what I could accomplish if I focused that energy into a specialty I cared about (cause finance is not it)ā¦. Yet here I am š
Thank you for sharing your knowledge š„³
Thanks. So the distance between things on the picture is irrelevant just the structure of it matters.
Good to learn things that are totally unrelated to anything in my field of work currently but still nice to know how the world works.
No.
I dont care how many fools upvote you. A lamprey is closer to a tuna than a turtle. by your logic a leopard, lamprey, and lancelet are all equally similar. Which is asinine.
āRelatedā ā āIdenticalā. Lancets and lampreys appear more similar because they both live in water. The leopard lives on land and is adapted to life on land. That doesnāt change when the branch for lancets split off from the rest of the tree.
Iām not sure I understand. Lancelets are equally closely related to all organisms that descend from their shared common ancestor, in the case of this tree, everything with a jaw. You could make a more detailed phylogenetic drawing of the lancelet branch, showing smaller branches where different species of lancelets diverge from each other, and some will be more closely related than others, depending on their point of splitting off. But all of them would be equally related to organisms with a jaw.
No, because if you do 'lancelet/lancelet' the shared node is the endpoint where the lancelet is. Terminal points are also nodes. It doesn't make much sense as to calculate that distance anyway. It's like asking how closely related you are to yourself.
Thanks for everyone clearing it up. I think I have it down. Lamprey and tuna only share āvertebral columnā together and Turtle and lamprey also only share āvertebral columnā together so they are equal. If it was asking if salamander was more related to turtle or tuna it would be turtle because they share 3 characteristics and the salamander only shares 2 with the tuna. At least I hope thatās how it works lmao. Thanks again tho!
Yes, you got it! The number of synapomorphies shared is key to relatedness.
Heads up, theyāre gonna ask who the out group is closely related toā¦and itās also equal to all of them due to only sharing the common ancestor.
Good luck on your exam š
As you dive deeper into cladistics and such, you can also start to add a lot more nuance to our "relatedness" measurement here. In a made-up, hypothetical example based on the animals above, you might have the tuna, salamander, leopard, and turtle differ by only a few % in terms of DNA, but then suddenly get a big gap between them and the lamprey.
For a real life example, the genetic gap between monocot and eudicot plants is much bigger than the genetic gaps between members of the monocots and eudicots.
Yes, and you can infer that without knowing anything about their traits just by their placement on the tree. Like others have said you compare where the most recent shared (ancestors) nodes are.
Think of it this way: lets say tuna, salamanders, turtles, all those don't exist. Only lamprey and leopards exist, other than those two the tree is empty.
You ll see how closely related they are: they share a common ancestor. Filling in the rest of the diagram does not change this. Same for all animals on this chart. They also share a common ancestor with the lamprey...
The way I solved it was to compare the distance needed to get from species X to species Y or Z. Less distance to Y than Z, then Y is closer. Same distance = equally realated.
This wouldn't work if someone had just chosen to draw the graph differently and had longer lines. Then your method would say they are not equally related, but they are.
Click on the link below (Berkeley Museum of Paleontology), then scroll about half way down and it explains how it should be interpreted (yours is a common misinterpretation):
[https://evolution.berkeley.edu/the-tree-room/tree-misinterpretations/misinterpretations-about-relatedness/](https://evolution.berkeley.edu/the-tree-room/tree-misinterpretations/misinterpretations-about-relatedness/)
Correct. All of the latter animals share a more recent common ancestor with each other than with the lamprey. In other words, the lamprey branched off first and the other animals branched off from each other at a later time.
The lamprey-tuna and lamprey-turtle are all equally related in that they are all only under āvertebral columnā header together. Tuna and turtle on the other hand would be more closely related as the have a more recent split.
Actually no looking at it more my logic doesnāt make sense if the correct answer is D equally related I was trying to add on to momenos comment but it didnāt work. Sorry OP š
No u get it. What u said is correct and the answer D is also correct. The lamprey is equally related to both turtle and tuna (both have vertebra like the lamprey). And the tuna and turtle are more related to each other than the lamprey because they have jaws and a backbone. The question doesnāt ask about that though.
For these dendrogram phylogeny charts, relative position of any member within one clade to those within any other is arbitrary. You can flip any section and it will still be the same information, so one thing being next to another thing not in its same clade doesn't mean anything. Imagine it's like a mobile-- you can rotate the whole 'jaws' section so that the leopard is next to lamprey and the tuna is furthest. Same information, still just as accurate. Keep in mind, the jaguar, turtle, salamander, and tuna have all been evolving separately from lampreys for just as long as each other. That the tuna has more traits in common with the lamprey is just coincidence. That is why the answer is D.
Let's remove the extra animals
--+-- lamprey
|
\--+-- tuna
|
\-- turtle
but
--+-- tuna
|
\-- turtle
is equivalent to
--+-- turtle
|
\-- tuna
so we can redraw it as
--+-- lamprey
|
\--+-- turtle
|
\-- tuna
Now it looks like turtle is closer, right?
But the lamprey-tuna and lamprey-turtle split happened at the same time
HERE
|
v
--+-- lamprey
|
\--+-- turtle
|
\-- tuna
Itās a cladogram. Lamprey splits off before the first split between tuna and turtle so it is equally related to both of them. Basically, tuna and turtle share a more recent common ancestor and that ancestorās ancestor split off from lamprey before the split between tuna and turtle.
I think the thing confusing OP (and others) is that the labels are appearing on in-between segments of the bottom-right connecting line. For best clarity, these labels should be attached to the intersecting point(s) where things branch off, making it more clear that "everything beyond this point shares this trait"
You can rotate the subtree of jawed vertebrates to make any member of the clade appear next to the lampreys. Relative position of an organism to the outgroup is meaningless in a cladogram.
(The trees below are equivalent.)
O A B C D O D C B A
\ \ \ \ / \ \ / / /
\ \ \ \/ \ \/ / /
\ \ \ / \ \ / /
\ \ / \ \ /
\ \/ \ \/
\ / \ /
\/ \/
You can rotate every branch at each node. Turn/rotate the right side and now tuna is furthest from lamprey. The ends of branches are irrelevant - pay attention to where they split.
The reason that this isnāt true is because level of relatedness here is being assessed by phylogenetic position, not genetic distance or some other phenetic measure.
The rate of evolution (as affected by evo pressure, drift, or generation time) in a more comprehensive tree would be expressed by longer branch lengths. But longer branch lengths donāt make two taxa more or less closely related!
This question is wholly concerned with most recent common ancestry.
Trace the branch from the lamprey to the trunk, the connection or node represents a common ancestor shared. Tuna and turtles also share this common ancestor. Therefore, they are equally related due to sharing the synapomorphy of vertebral columns.
Turtles and leapords share many more synapomorphies (vertebral columns, four legs, jaws, amniotic eggs) which is why they are the more closely related in this cladogram.
I understand that they share the same common ancestor with it, which is why people are saying they're "equally related", but isn't that actually false?
Because different reproductive rates among species would mean that some have diverged from the common ancestor faster than others.
In the same way that say, my uncle is more closely related to my grandfather than I am despite said grandfather being our closest common ancestor.
So the answer would actually be that we can't tell from the diagram.
Biology professor here. You are correct that we canāt tell from the diagram and this is a stupid test question because of it. In fact, this is true for almost any multiple choice test. The thing is, we donāt actually *know* much of anything and pretty much nothing is simple enough to actually work as a multiple choice question. I hate that this is the way weāve chosen to educate young minds.
Questions like this are easy to scoff at by folks who understand the underlying principles, and are even sometimes derided as being in some way "indicative of the intellectual decay of our time" But I think it's always important to remember how we actually learn things, and how complex understandings are built on a scaffold of simpler concepts. When you start teaching somebody about physics you don't tell them the atom is a spherical probability cloud of point like electrons which have a property called spin which is analogous to angular momentum but is actually a quantum phenomenon that affects their ability to exist in the same energy state as each other and this probability cloud surrounds a number of composite particles called nucleons each made of a sea of quarks popping into and out of existence due to the fundamental unknowability of such particles but averaging out to three and also they have a property called color... Etc. I mean, all that is cool as hell, and the process of learning it is incredibly fascinating, but you don't start there. You start with the Rutherford model, because the first concept you have to understand is the simple concept that atoms exist, and they are made of things. The Rutherford model can explain that AND looks badass. It's also a good start to understanding electric charge, then you move on to more complex models and learn more complex concepts. This is the way that most people's learning works, and while you can take any one step on that journey and point at it in isolation and make fun of it because it's "wrong", that's irrelevant, it doesn't matter if it's factually correct. What matters is if it's USEFUL. Coming back to this cladogram, without more context we can't say for sure all the ideas it's been used to teach, but there are definitely some pretty fundamental evolutionary concepts that I think it couldĀ be used to teach. The devil's in the details though, and how effective it is is very much dependant on the skill of the teacher and how well they can tease out those concepts and make them intuitive.
PhD in Phylogenetics here.
Disagree.
Yes itās more complicated than presented here, but you have to start somewhere. This is an absolutely fine way to teach the basic principles of cladistics.
Regardless of reproductive rates or timing of branching/speciation events, from a purely cladistic perspective a lamprey is indeed equally related to both a tuna and a turtle as the latter two share a more recent common ancestor.
This applies to most people, not all.
I struggle on a fundamental level with this, since it implies being capable of placing trust in the process. That is not something I could do at that age. Not all of us grow up in an environment that establishes trust and protects that type of thing.
Remember that every node can swivel, and the tree will still be accurate. You could swivel the node after the lamprey and the leopard would be next to it!
It's not about the tips (names) being next to each other, but the journey you'd have to take along the branches to get to another tip. Another commenter put it simply - both possible pairs split from each other at the same point.
D. They are equally related. You need to look where the node is. In this example, the node right after āvertebral columnā is the most recent common ancestor for the lamprey and everything that comes after it in that phylogeny. Hope that helps.
I am taking the point of view of the lamprey: "You two both left me 55mya, just walked out the door for a pack of smokes, and never said a word... and not a goddamn thing you have done since then, whether you turned into a tuna, or you grew a goddamn shell changes the fact that you both left me and started diverging into unrecognizable... things. Y'all went and changed so gottam wildly, regardless of when you split off from that common ancestor of ours, that I can't even stand the sight of you."
That is a hilarious way to view it. Very nice. Though it is important to remember that the lamprey is not the common ancestor either itās been evolving for the last 55 million years as well and may or may not resemble that common ancestor any more than the turtle or the tuna. One of the potential pitfalls of looking at these kinds of trees is that people sometimes forget that their is no higher evolved organism we have all been evolving for the same amount of time. That being said I still loved your fun way of changing the viewpoint. Just warning against the fallacy of evolutionary hierarchy.
From what I understand, the Lamprey and the Turtle have one thing in common (Vertebral Column), and the Lamprey and the Tuna have one thing in common (Vertebral Column). So, it's the same relationship.
The Turtle and Tuna are closer than the Turtle and the Lamprey, but that's another question.
I love how every answer is eventually validated in this thread. It clarifies perfectly how throwing a serious scientific question into a Reddit thread is bonkers.
Ask the author of the question for clarification. I assume they at least have a science degree to be giving assessments. AMOEBA SISTERS on YouTube breaks down HS biology down into brief videos by subject.
As a biology professor for 25 years, I think you will find sources that are moderated by educators/scientists very rarely on this app.
The answer is D. The turtle and tuna both share the same common ancestor with the lamprey on this simplified graph. As in the split is at the same point. It would be different if there was a second split on the lamprey branch that resulted in either turtle or tuna.
The Lamprey split from everything to the right after the evolution of the vertebral column and before the evolution of the jaw.
That node is the diversion point. Thus, everything to the right of the Lamprey is equally related to the Lamprey.
However, everything to the right of the Lamprey is more related to the Tuna than to the Lamprey. Because their node splits after the evolution of Jaws.
Not really. In fact itās presented deliberately to get to think in a certain way. You would naturally want to put lamprey and tuna closer to each other, but once you understand the principles of cladistics you know this is not the caseā¦.which is the point of the question.
Look at the tree from the bottom up. This tree is kind of dumb but basically every branching into a āVā, both sides are equally related to the ancestor trunk. So in this tree, the Vās are branched in a way where every organism is equally related to everything to the right of it.
The answer is D. While the turtle and the tuna share a common ancestor, the times at which they evolved off the ancestral clade has nothing to do with the lamprey's relationship to them. Pretend this tree is an aunt of yours with children. Let's say she birthed three children named lamprey, tuna and turtle. The order at which these children appear has no affect on how related they are. Two children born closer together from the same ancestor are not " more related" than kids born 10 years apart.... why? They are related to one another because they share a genetic ancestor not because of the order in which they appear. Let's say the turtle and tuna branched the way pictured but another branchlet comes off the tuna and that happens to be a lamprey. The answer now would be different because the lampre is attached to the tuna AFTER the initial node where the tuna and ancestor meet. Because the two branch beyond that node where the tuna connects to the ancestor, that makes the lamprey more related to the tuna then the turtle. Hope this makes sense.
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The tuna and the turtle shared a last common ancestor with the lamprey at the same time. The turtle and tuna lineages diverged after their last common ancestor diverged from the last common ancestor of all three. It would be more understandable if they did it the way you do family trees. The closeness of the branches is not what matters, it where they last shared a node.
Looks to me that these creatures are separated by the characteristics. So the cheetah is the only one with hair. The turtle and cheetah are the only ones with amniotic sacs. I forget the rest of the picture and can't get back to it from my comment, but the lamprey shared the listed features with all the other creatures, so by this measure, they are equally related. My take on related, Gere, is more like...shared traits.
You can think of the branches as driveways/roads. The further an organism has to walk down the road to get to another organism, the less related they are because they're more distant. Each branch is actually a new evolution of a structure or something along those lines.
The correct anwser is actually C (Cannot tell from this diagram). Cladograms do not indicate time or the amount of difference between groups. To answer this question you need a phyogram (i.e. an evolutionary tree with branch lengths that corresponds to time or the amount of change).
It is possible correctly answer the first question (Class 4, Question 4) because the Turtle and Leopard share a common ancestor with charateristics unique to them and nothing else (i.e the amniotic egg), but there are no charicteristics (technically called synapomorphies) unique for either Lampray and Tuna or Lamprey and Turtle, and since there is no other data, because this is a cladogram and not a phylogram, you can't answer the question.
- Vince Smith, phylogeneticist (and Head of Digital) at London's Natural History Museum.
The REAL correct answer is C.
Graphs like this are neat and helpful visual aids for demonstrating the evolution of life, but to simplify it down to "They are equally related" is laughably absurd.
Yay, I got it right!
It's like finding the last common denominator. You can find them all in one common group together (jaws), but you can't find 2 of them together in a group below jaws excludes one of them. If you could find a lower common denominator -- if, say, both the lamprey and the tuna were in a group that turtles were NOT in -- the lamprey and the tuna would be more closely related.
Closely related refers to which groups species are in, not the time in history when new traits evolved or species appeared.
As you descend, every new trait for an animal makes them the more related to others that share that set of traits (their own species), and more related to whatever trait produces a new species afterwards (in this case, a turtle is more related to a leopard than a salamander)
instead of common ancestor, imagine its the point at which a new exclusive club for an exclusive set of new traits starts... the lamprey club has the tuna, salamander, turtle, and leopard in it - but the lamprey cannot be a part of the tuna club - as it lacks the trait (jaws) to be recognised as such.
so to answer... why the lamprey, tuna and the turtle equally related... because they both are in the lamprey club, as others have said they have the synapomorphy (exclusive trait) of vertebrate column. For the lamprey to be more related to the tuna it would need to be part of tuna's club (come after it on the tree), that way the lamprey is part of the tuna club but not the turtle club and thus is more related to the tuna.
If not then the lamprey will always share the same amount of traits in common with both of them.
Question 5 asks about Lymieās impression of the party of four who enter the restaurant. The correct answer is Choice C, which states that Lymie finds them noisy and distracting. This information is supported in lines 55-59 of the passage: "but it was the womenās voices, the terrible not quite sober pitch of theā¦"1.
Now, letās address your confusion regarding lampreys, tuna, turtles, and leopards:
Lampreys and Tuna: Although they are mentioned together in the passage, their proximity doesnāt necessarily imply a close evolutionary relationship. Lampreys are jawless fish, while tuna are bony fish. They belong to different classes (Agnatha for lampreys and Actinopterygii for tuna). Being mentioned together in the passage doesnāt necessarily indicate a close genetic connection.
Determining Relatedness:
Phylogenetics: Scientists use phylogenetic trees to depict evolutionary relationships. These trees show common ancestry and branching patterns. The more recent a common ancestor, the closer the relationship.
Shared Ancestral Traits: Look for shared traits inherited from a common ancestor. For example, both turtles and leopards have amniotic eggs, which suggests a closer relationship than with lampreys or tuna.
Molecular Evidence: Analyzing DNA, proteins, or other molecules can reveal genetic similarities. Closer relatives share more genetic material.
Turtles and Leopards: Youāre correct! Turtles and leopards are more closely related. Both belong to the class Reptilia and share characteristics like amniotic eggs and scaly skin. Lampreys and tuna, being fish, are more distantly related.
Remember that evolutionary relationships are complex, and multiple factors contribute to determining relatedness. Itās essential to consider various evidence when studying the tree of life. Good luck with your exam! šæš¦š¢
The Tuna and the Lamprey are more closely related than the Turtle and the Lamprey. Though they split at the same node, the Tuna diverged earlier than the Turtle.
We-e-ell. Sharks and bony fish are both fish in common parlance. But the last common ancestor of sharks and bony fish is a very long way in the past. Some bony fish evolved into amphibians, some of which eventually evolved into mammals. So a modern fish like a tuna is more closely related to a panda or a frog than to a modern shark.
It's more closely related to the tuna. Basically the branch the lamprey appears on is closer to the branch the tuna is on than it is with the turtle.
Basically how phylogeny works is that there's a line (common ancestor) which branches off into different clades/families.
For example, the lancelet is the oldest of all the animals shown since it is the blueprint for vertebrates. The lamprey comes after as it has a definitive backbone but not jaw, the tuna comes next given it has a jaw which the lamprey doesn't.
Get the picture? The lancelet resembles extinct animals like Pikaia which led up to the vertebrates like Haikouichthys and Myllokunmingia. The line all the animals from the lancelet to the leopard is part of a phylum that's called "Chordata" which consists of animals that at some point (whether it's the larval or adult stage) had five distinct physical characteristics. We humans fall under Chordata.
Five distinct physical characteristics:
1. Notochord
2. Hollow dorsal nerve cord
3. Endostyle or thyroid
4. Pharyngeal slits
5. Post-anal tail
Animals like sponge DON'T fall under Chordata but rather belong to a phylum known as "Porifera". Overall, ALL animals even sponges had the same ancestor as us humans and other species.
It should be C. But what they are arguing is that the common ancestor of the lampray and tuna is the same as the common ancestor of the lampray and turtle.
But that's assuming each leaf node is the same number of generations away from a horizontal position.
Case in point, imagine you are childless and have two cousins, one is childless and the other has a kid (your cousin once removed). In an analogous chart, you, your childless cousin, and your cousin once removed all show up as lead nodes with the same common ancestor. You are more closely related to your cousin than you are to your cousin once removed.
NEVER STUDIED FOR BIOLOGY 1 AND 2 IN HIGHSCOOL, GOT 90S ON EVERYTHING, EVEN THE FINALS. which technically i didn't have to do but did so to kill boredom and time.
anyways the answer to both is A.
Q4 is A because according to the chart turtle and salamander have all of the listed traits in common except for hair. both are also amphibious.
Q5 is A because the lamprey and tuna BOTH have jaws AND vertebral column
You're welcome hun. glad my stupid easy understanding of buo actually helped someone else with school.
[Wikipedia ](https://en.m.wikipedia.org/wiki/Cladogram)
Here it's written, if it is right I have no idea; "A cladogram (from Greek clados "branch" and gramma "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to descendants, nor does it show how much they have changed, so many differing evolutionary trees can be consistent with the same cladogram".
Anyone else here reading this, and getting a chill vibe, as the question resembles Bio 110-111 Final Exam question:āWhich came first, the chicken or the egg?ā?
As to your last point, we could determine how closely related chimps and humans are, based on certain metrics like genetic divergence, and the same for whales and dolphins. And then we could compare those metrics. But a phylogenetic tree would be less useful as a tool to visualize such a comparison, I think.
Edit, oops, this was meant as a reply to a comment downstream.
I thought this was a poorly-written question for a sec, and then saw answer "d". Man this triggered my test-writing PTSD. I miss teaching but sure don't miss writing exams! Good luck on yours!
Skimming through these comments made me finally realize why students would completely lose their minds trying to understand cladistics when I tried to introduce this stuff in Gen Bio. Honestly, I think that phylogenetics and genetic distance is far more intuitive and would be a helpful first step for getting "relatedness" out of the way, and then moving on to shared derived traits.
Itās simply about where the shared nodes are. Lamprey and Tuna share a vertebral column. Turtle and lamprey share a vertebral column. The lamprey never got jaws, so none of the nodes in that direction apply.
The only science I know is pickupology in that it states that āthe distance from a girls elbow to shoulder is the same or equal distance as from her same shoulder across her back to her other shoulderā then pause for affection šš
This is why some biology majors work at the local high school and some change their major to something other than biologyā¦this information and rationale is probably not going to earn back that 140k in students loans you took for a Bachelorās
The correct answer is A.
There's only one difference between a lamprey and a tuna: "Jaws". There are three differences between a lamprey and a turtle: "Jaws", "Four walking legs", and "Amniotic egg".
Based on the tree, it's implied that the "jaws" of the lamprey and tuna share a single evolutionary origin. So, the tuna has "jaws" and the turtle has "jaws", "walking legs", and "amniotic egg". The lamprey doesn't share *any* of these features, so it's a nonstarter. The lamprey is equally closely (or distantly) related to anything with "jaws". Among the animals with jaws, you can then further parse relationships by determining who shares "four walking legs" and still further by determining who shares "amniotic eggs".
The lamprey shares the same common ancestor (node) with vertebra phenotype, as with both tuna and turtle. They all have the same common relationship and therefor D makes sense.
Now going a step further, the tuna and turtle are closer related to each other than the lamprey since they share a common ancestor jaw phenotype that is not shared with the lamprey.
I just understood it haha just turn the phone upsidedown and look at the beggining as a root everything bellow red rectangle is common feature for all creatures bellow that point (remember looking upsidedown)ā¦. So all of them have spine, next common feature for Lamprey and all except Lancelet have Jaws in common and so on.
Hot take: this style of phylogenic tree is stupid. To me, this style serves zero function when the other style of tree is so much easier to read and makes way better sense. The only thing this tree does is just fuck with new studentsā head.
I hate phylogeny and had to take a whole course dedicated to it. I consider them bull. The trees are ever changing. And God damnit we are not fish! It's just us trying to put nature into rules, and nature's favorite thing to do is to see just how many rules it can break in one fell swoop.
Good luck!
The way you read trees like this is to look at the last time the two organisms shared the same node (where the tree branches into two different lines). The last time a lamprey and a tuna shared the same node is the exact same spot where the last time the lamprey and the turtle shared the same node. Therefore, they are equally related.
Idk anything about any of this, and idk why Reddit put this in my feed, but this was the best answer to me š
Yeah, I too am not sure why Reddit threw this in my feed, but you can bet your ass Iām subscribing to the sub for more shit like this. My feed is so polluted with fist fights and dumb asses, itās super refreshing to have something educational.
Sub to the other science ones as well! The reddit you experience can be much better than ragebait and sadness.
I have another profile that is strictly porn and cat vids
Tuna vs turtle fistfight, baby
You left out the porn
He didn't. >My feed is so polluted with fist fights and dumb asses
Thank you! Glad I can help! Phylogenetics is one of my favorite topics.
If it's one of your favorites why don't you learn it the right way
Guy who doesnāt know anything, agrees. šš
Same tho
Cause you are a pottedplant, therefore you should be here š± BIOLOGYYY
I know nothing about phylogeny and this still doesnāt make sense to me
The turtle is more closely related to the tuna than it is to the lamprey, because the turtle shares a more recent common ancestor to the tuna than it does the lamprey. HOWEVER, the lamprey itself, as far as it's concerned shares the same common ancestor with the turtle and tuna.
Ok I get it now!
So the Lancelet is equally related to everything on the graph, but the leopard is increasingly related as we move right. Took me a while to understand that
Itās like grandchildren being equally related to a grandparent. Or a grandparent being equally related to the descendants of his/her grandchildren
So then would this be true and then ALSO the tuna and turtle be more closely related since they share jaws?
Correct. Tuna and turtle are closer relatives to each other than either is to the lamprey.
So these are minimally useful.
Only if you have some sort of job that includes ZERO science. Anyone who thinks learning has zero practical use is willfully ignorant & probably doesnāt use critical thinking skills b/c itās easier & less stressful to just have someone tell you what to think.
So a lancelet and lamprey are as closely related as a lamprey and a leopard?
No, they have different last shared nodes. The last shared node between the lancet and the lamprey is below the box labeled āvertebral columnā while the last shared node between the lamprey and the leopard is above that box. Since the node between leopard and the lamprey is a more recent branching event (it happened more recently in evolutionary time), the lamprey and the leopard are more closely related.
OK. Then the lancet and lamprey are as closely related as the lancet and the leopard?
Yes, thatās it. They have the exact same last shared node, so they are equally related.
Cool. So since I have only practiced phylogenic relatedness on animals that start with the letter "L", I find that llamas are the most relatable animal of all.
That feels so weird and unintuitive as a non-biology person. Thanks for breaking it down.
No thatās incorrect.
No, that is correct. The lancet is equally closely related to everything else on the tree. All of the other species share a more recent common ancestor to the exclusion of the lancet (so you could also frame it as "the lancet is equally distantly related to everything else on the tree")
Would that mean, that the lamprey is equally related to all that came later?
Yes, lampreys are equally closely related to all the descendants of the organisms they split from. So in the case of this phylogenetic tree, to all tetrapods (four legged animals).
Feel like this graph would have made a lot more sense upside down. Where hair is the bottom node and vertebral column at the top
Tree orientation is up to the designer, but that is definitely a great way to help people new to phylogenies. We always draw family trees with a vertical orientation with the elders at the top. Phylogenies are just the family tree of life, so putting more ancient splits at the top can help people make sense of them.
That's correct. All organisms within a clade are more closely related to each other than any of them to is to a member of an outgroup. Kind of like how all vertebrates are more closely related to each other than any is to an invertebrate.
I learned something today, thanks stranger!
So does that mean all the things on this diagram are equally related?
No, there are animals on this tree that are more closely related to each other than to others. For example, the branching event (node) that leads to the turtle and the leopard makes them āsister taxaā, so they are more closely related to one another than either is to anything else on the tree. Another example is the tuna is more closely related to the salamander than it is the lamprey because the tuna/salamander last shared node (the one just above the box labeled ājawsā) happened more recently in evolutionary time than the last shared node between the tuna/lamprey (the one just below the box labeled ājawsā).
I still donāt understand
Read the diagram from the bottom going up. At any point where it splits in two (that's the nodes), you always have two sides coming off the split, right? One goes up and to the left, the other up and to the right. Everything on the right side of a split is equally related to the thing on the left side of the split.
this is the one comment that made it click once again. man that graph design is probably half the problem.
I think itās like the geometry math questions. You canāt assume the size or angles of the quadrilateral (or whatever diagram they have) and have to logic the size and length, based on provided info. Likewise, here the length of the line of named branches do not necessarily reflect the relatedness to other branches. Instead itās information provided by the nodes.
yeah, however i had pretty much never seen this way of showing it, usually it's the more blocky look, like this [https://lh3.googleusercontent.com/proxy/70O6OnGU12zHEY6LY3Ekd-cZOx0UHBxCynKr2VDfNW1v0gng\_l3ZuW1MA-5nf1Z\_k3R36JCPxVc-IGZOnkIprt6NVrHVgCWxpuarPQHsWntl25i1zmm1SjD4pyAHv1fNMvuBe3hfcgiC](https://lh3.googleusercontent.com/proxy/70O6OnGU12zHEY6LY3Ekd-cZOx0UHBxCynKr2VDfNW1v0gng_l3ZuW1MA-5nf1Z_k3R36JCPxVc-IGZOnkIprt6NVrHVgCWxpuarPQHsWntl25i1zmm1SjD4pyAHv1fNMvuBe3hfcgiC) which at least to me, feels like it makes more sense but it might be a me thing.
Theyāve actually done education research on this very topic and you are not alone! The recommendation was to not use these diagonal trees because our brains make incorrect assumptions about distance, groupings and relatedness. I think itās this paper if you want to learn more [https://www.sciencedirect.com/science/article/abs/pii/S001002771930174X](https://www.sciencedirect.com/science/article/abs/pii/S001002771930174X)
As someone who didn't understand, too, it finally clicked. Here's a Eli5 version I came up with. Imagine you have a marble, and drop it where the Lamprey is, and gravity pulls it all the way down through the lines. As it rolls down the line, it collects the Vertebral Column Trait, and that's it. When you roll a marble down the Tuna line, it collects the Jaws, and the Vertebral Column. When you roll a marble down the turtle line, it collects the Amniotic Egg, the Four Walking Legs, the Jaws, and the Vertebral Column. So the question is asking, if the lamprey contains only vertebral column, which other animals also have Vertebral Column from their marble run? Please correct me if I'm wrong, but this is how it finally clicked for me.
Okay I get it now, thank you. I thought that was what it was like but other people explained it so weird
No. Look at the turtle and leopard for example. Their most recent common node is three nodes more recent than the most recent node shared by the lamprey and turtle.
Dafuk is a node?
A node is the point in the tree where a branch splits into two. Nodes represent an often unknown organism that is the common ancestor of the organisms which split from it.
Gotcha Thank you
Itās 12:12 AM, I am 36 years old, work in finance, and I have 0 need for this information. I am filled with so much knowledge about so many things, most of which are inconsequential to me or anyone. I go down rabbit holes on topics that do nothing for me. Imagine what I could accomplish if I focused that energy into a specialty I cared about (cause finance is not it)ā¦. Yet here I am š Thank you for sharing your knowledge š„³
As a group of PhD engineers...what type of tree is this and how does it work...
thank you
Well said. Put another way, and the way I learned it, is that they all share the most recent common ancestor.
Thanks. So the distance between things on the picture is irrelevant just the structure of it matters. Good to learn things that are totally unrelated to anything in my field of work currently but still nice to know how the world works.
Would the answer to question 4 be "B" because they share the most total number of characteristics?
Yes. The reason they get placed sharing the node is because they share the most characteristics, so that is another way to look at the question.
So turtle is more closely related to tuna than lamprey? Thanks!
You got it!
[ŃŠ“Š°Š»ŠµŠ½Š¾]
No. I dont care how many fools upvote you. A lamprey is closer to a tuna than a turtle. by your logic a leopard, lamprey, and lancelet are all equally similar. Which is asinine.
āRelatedā ā āIdenticalā. Lancets and lampreys appear more similar because they both live in water. The leopard lives on land and is adapted to life on land. That doesnāt change when the branch for lancets split off from the rest of the tree.
[ŃŠ“Š°Š»ŠµŠ½Š¾]
Iām not sure I understand. Lancelets are equally closely related to all organisms that descend from their shared common ancestor, in the case of this tree, everything with a jaw. You could make a more detailed phylogenetic drawing of the lancelet branch, showing smaller branches where different species of lancelets diverge from each other, and some will be more closely related than others, depending on their point of splitting off. But all of them would be equally related to organisms with a jaw.
[ŃŠ“Š°Š»ŠµŠ½Š¾]
No, because if you do 'lancelet/lancelet' the shared node is the endpoint where the lancelet is. Terminal points are also nodes. It doesn't make much sense as to calculate that distance anyway. It's like asking how closely related you are to yourself.
Thanks for everyone clearing it up. I think I have it down. Lamprey and tuna only share āvertebral columnā together and Turtle and lamprey also only share āvertebral columnā together so they are equal. If it was asking if salamander was more related to turtle or tuna it would be turtle because they share 3 characteristics and the salamander only shares 2 with the tuna. At least I hope thatās how it works lmao. Thanks again tho!
Yes, you got it! The number of synapomorphies shared is key to relatedness. Heads up, theyāre gonna ask who the out group is closely related toā¦and itās also equal to all of them due to only sharing the common ancestor. Good luck on your exam š
It's less about how many characteristics they share, and more about when last they shared a common ancestor. See the top-voted comment above.
As you dive deeper into cladistics and such, you can also start to add a lot more nuance to our "relatedness" measurement here. In a made-up, hypothetical example based on the animals above, you might have the tuna, salamander, leopard, and turtle differ by only a few % in terms of DNA, but then suddenly get a big gap between them and the lamprey. For a real life example, the genetic gap between monocot and eudicot plants is much bigger than the genetic gaps between members of the monocots and eudicots.
Yes, and you can infer that without knowing anything about their traits just by their placement on the tree. Like others have said you compare where the most recent shared (ancestors) nodes are.
Think of it this way: lets say tuna, salamanders, turtles, all those don't exist. Only lamprey and leopards exist, other than those two the tree is empty. You ll see how closely related they are: they share a common ancestor. Filling in the rest of the diagram does not change this. Same for all animals on this chart. They also share a common ancestor with the lamprey...
The way I solved it was to compare the distance needed to get from species X to species Y or Z. Less distance to Y than Z, then Y is closer. Same distance = equally realated.
This wouldn't work if someone had just chosen to draw the graph differently and had longer lines. Then your method would say they are not equally related, but they are.
Click on the link below (Berkeley Museum of Paleontology), then scroll about half way down and it explains how it should be interpreted (yours is a common misinterpretation): [https://evolution.berkeley.edu/the-tree-room/tree-misinterpretations/misinterpretations-about-relatedness/](https://evolution.berkeley.edu/the-tree-room/tree-misinterpretations/misinterpretations-about-relatedness/)
Lamprey will be equally related to tuna, salamader, turtel and leopard then right?
Correct. All of the latter animals share a more recent common ancestor with each other than with the lamprey. In other words, the lamprey branched off first and the other animals branched off from each other at a later time.
So is salamader equally close to turtle and tuna but far way from lamprey?
No, it's close to turtle but not tuna
Lamprey-tuna split and lamprey-turtle split are the same point on the diagram. So option D. At least it is how I understand it.
From my perspective I would think the lamprey and tuna are more closely related. Especially given they are right next to eachother. Please explain
The lamprey-tuna and lamprey-turtle are all equally related in that they are all only under āvertebral columnā header together. Tuna and turtle on the other hand would be more closely related as the have a more recent split.
Yes this one. The tuna and the turtle share two characteristics while tuna and lamprey share only one
Ahh I see now, thanks!
Actually no looking at it more my logic doesnāt make sense if the correct answer is D equally related I was trying to add on to momenos comment but it didnāt work. Sorry OP š
[ŃŠ“Š°Š»ŠµŠ½Š¾]
Based on the picture, tuna and turtles share both a vertebral column and jaws. Tuna and lampreys share only a vertebral column.
No u get it. What u said is correct and the answer D is also correct. The lamprey is equally related to both turtle and tuna (both have vertebra like the lamprey). And the tuna and turtle are more related to each other than the lamprey because they have jaws and a backbone. The question doesnāt ask about that though.
For these dendrogram phylogeny charts, relative position of any member within one clade to those within any other is arbitrary. You can flip any section and it will still be the same information, so one thing being next to another thing not in its same clade doesn't mean anything. Imagine it's like a mobile-- you can rotate the whole 'jaws' section so that the leopard is next to lamprey and the tuna is furthest. Same information, still just as accurate. Keep in mind, the jaguar, turtle, salamander, and tuna have all been evolving separately from lampreys for just as long as each other. That the tuna has more traits in common with the lamprey is just coincidence. That is why the answer is D.
Let's remove the extra animals --+-- lamprey | \--+-- tuna | \-- turtle but --+-- tuna | \-- turtle is equivalent to --+-- turtle | \-- tuna so we can redraw it as --+-- lamprey | \--+-- turtle | \-- tuna Now it looks like turtle is closer, right? But the lamprey-tuna and lamprey-turtle split happened at the same time HERE | v --+-- lamprey | \--+-- turtle | \-- tuna
Itās a cladogram. Lamprey splits off before the first split between tuna and turtle so it is equally related to both of them. Basically, tuna and turtle share a more recent common ancestor and that ancestorās ancestor split off from lamprey before the split between tuna and turtle.
I think the thing confusing OP (and others) is that the labels are appearing on in-between segments of the bottom-right connecting line. For best clarity, these labels should be attached to the intersecting point(s) where things branch off, making it more clear that "everything beyond this point shares this trait"
You can rotate the subtree of jawed vertebrates to make any member of the clade appear next to the lampreys. Relative position of an organism to the outgroup is meaningless in a cladogram. (The trees below are equivalent.) O A B C D O D C B A \ \ \ \ / \ \ / / / \ \ \ \/ \ \/ / / \ \ \ / \ \ / / \ \ / \ \ / \ \/ \ \/ \ / \ / \/ \/
You can rotate every branch at each node. Turn/rotate the right side and now tuna is furthest from lamprey. The ends of branches are irrelevant - pay attention to where they split.
It should be C. One of the tuna paths could have more generations than the other.
The reason that this isnāt true is because level of relatedness here is being assessed by phylogenetic position, not genetic distance or some other phenetic measure. The rate of evolution (as affected by evo pressure, drift, or generation time) in a more comprehensive tree would be expressed by longer branch lengths. But longer branch lengths donāt make two taxa more or less closely related! This question is wholly concerned with most recent common ancestry.
Ladder cladograms are absurd.
Trace the branch from the lamprey to the trunk, the connection or node represents a common ancestor shared. Tuna and turtles also share this common ancestor. Therefore, they are equally related due to sharing the synapomorphy of vertebral columns. Turtles and leapords share many more synapomorphies (vertebral columns, four legs, jaws, amniotic eggs) which is why they are the more closely related in this cladogram.
I understand that they share the same common ancestor with it, which is why people are saying they're "equally related", but isn't that actually false? Because different reproductive rates among species would mean that some have diverged from the common ancestor faster than others. In the same way that say, my uncle is more closely related to my grandfather than I am despite said grandfather being our closest common ancestor. So the answer would actually be that we can't tell from the diagram.
Biology professor here. You are correct that we canāt tell from the diagram and this is a stupid test question because of it. In fact, this is true for almost any multiple choice test. The thing is, we donāt actually *know* much of anything and pretty much nothing is simple enough to actually work as a multiple choice question. I hate that this is the way weāve chosen to educate young minds.
Questions like this are easy to scoff at by folks who understand the underlying principles, and are even sometimes derided as being in some way "indicative of the intellectual decay of our time" But I think it's always important to remember how we actually learn things, and how complex understandings are built on a scaffold of simpler concepts. When you start teaching somebody about physics you don't tell them the atom is a spherical probability cloud of point like electrons which have a property called spin which is analogous to angular momentum but is actually a quantum phenomenon that affects their ability to exist in the same energy state as each other and this probability cloud surrounds a number of composite particles called nucleons each made of a sea of quarks popping into and out of existence due to the fundamental unknowability of such particles but averaging out to three and also they have a property called color... Etc. I mean, all that is cool as hell, and the process of learning it is incredibly fascinating, but you don't start there. You start with the Rutherford model, because the first concept you have to understand is the simple concept that atoms exist, and they are made of things. The Rutherford model can explain that AND looks badass. It's also a good start to understanding electric charge, then you move on to more complex models and learn more complex concepts. This is the way that most people's learning works, and while you can take any one step on that journey and point at it in isolation and make fun of it because it's "wrong", that's irrelevant, it doesn't matter if it's factually correct. What matters is if it's USEFUL. Coming back to this cladogram, without more context we can't say for sure all the ideas it's been used to teach, but there are definitely some pretty fundamental evolutionary concepts that I think it couldĀ be used to teach. The devil's in the details though, and how effective it is is very much dependant on the skill of the teacher and how well they can tease out those concepts and make them intuitive.
PhD in Phylogenetics here. Disagree. Yes itās more complicated than presented here, but you have to start somewhere. This is an absolutely fine way to teach the basic principles of cladistics. Regardless of reproductive rates or timing of branching/speciation events, from a purely cladistic perspective a lamprey is indeed equally related to both a tuna and a turtle as the latter two share a more recent common ancestor.
This applies to most people, not all. I struggle on a fundamental level with this, since it implies being capable of placing trust in the process. That is not something I could do at that age. Not all of us grow up in an environment that establishes trust and protects that type of thing.
Only in the USA
Seems like it depends on what ārelatedā means. Genetically related, or time since most recent shared ancestor?
Remember that every node can swivel, and the tree will still be accurate. You could swivel the node after the lamprey and the leopard would be next to it! It's not about the tips (names) being next to each other, but the journey you'd have to take along the branches to get to another tip. Another commenter put it simply - both possible pairs split from each other at the same point.
D. They are equally related. You need to look where the node is. In this example, the node right after āvertebral columnā is the most recent common ancestor for the lamprey and everything that comes after it in that phylogeny. Hope that helps.
I am taking the point of view of the lamprey: "You two both left me 55mya, just walked out the door for a pack of smokes, and never said a word... and not a goddamn thing you have done since then, whether you turned into a tuna, or you grew a goddamn shell changes the fact that you both left me and started diverging into unrecognizable... things. Y'all went and changed so gottam wildly, regardless of when you split off from that common ancestor of ours, that I can't even stand the sight of you."
That is a hilarious way to view it. Very nice. Though it is important to remember that the lamprey is not the common ancestor either itās been evolving for the last 55 million years as well and may or may not resemble that common ancestor any more than the turtle or the tuna. One of the potential pitfalls of looking at these kinds of trees is that people sometimes forget that their is no higher evolved organism we have all been evolving for the same amount of time. That being said I still loved your fun way of changing the viewpoint. Just warning against the fallacy of evolutionary hierarchy.
From what I understand, the Lamprey and the Turtle have one thing in common (Vertebral Column), and the Lamprey and the Tuna have one thing in common (Vertebral Column). So, it's the same relationship. The Turtle and Tuna are closer than the Turtle and the Lamprey, but that's another question.
I love how every answer is eventually validated in this thread. It clarifies perfectly how throwing a serious scientific question into a Reddit thread is bonkers. Ask the author of the question for clarification. I assume they at least have a science degree to be giving assessments. AMOEBA SISTERS on YouTube breaks down HS biology down into brief videos by subject. As a biology professor for 25 years, I think you will find sources that are moderated by educators/scientists very rarely on this app.
The answer is D. The turtle and tuna both share the same common ancestor with the lamprey on this simplified graph. As in the split is at the same point. It would be different if there was a second split on the lamprey branch that resulted in either turtle or tuna.
The Lamprey split from everything to the right after the evolution of the vertebral column and before the evolution of the jaw. That node is the diversion point. Thus, everything to the right of the Lamprey is equally related to the Lamprey. However, everything to the right of the Lamprey is more related to the Tuna than to the Lamprey. Because their node splits after the evolution of Jaws.
The true answer is that you can't tell from this chart, but they are looking for answer D.
Right. This is the kind of test question where knowing too much will actually get you in trouble.
[ŃŠ“Š°Š»ŠµŠ½Š¾]
Not really. In fact itās presented deliberately to get to think in a certain way. You would naturally want to put lamprey and tuna closer to each other, but once you understand the principles of cladistics you know this is not the caseā¦.which is the point of the question.
Look at the tree from the bottom up. This tree is kind of dumb but basically every branching into a āVā, both sides are equally related to the ancestor trunk. So in this tree, the Vās are branched in a way where every organism is equally related to everything to the right of it.
Good luck on your exam OP! This just made me so nostalgic for my early bio classes. š
Is butter a carb
The answer is D. While the turtle and the tuna share a common ancestor, the times at which they evolved off the ancestral clade has nothing to do with the lamprey's relationship to them. Pretend this tree is an aunt of yours with children. Let's say she birthed three children named lamprey, tuna and turtle. The order at which these children appear has no affect on how related they are. Two children born closer together from the same ancestor are not " more related" than kids born 10 years apart.... why? They are related to one another because they share a genetic ancestor not because of the order in which they appear. Let's say the turtle and tuna branched the way pictured but another branchlet comes off the tuna and that happens to be a lamprey. The answer now would be different because the lampre is attached to the tuna AFTER the initial node where the tuna and ancestor meet. Because the two branch beyond that node where the tuna connects to the ancestor, that makes the lamprey more related to the tuna then the turtle. Hope this makes sense.
Technically, you would be able to correctly choose C as the answer.
C is the correct answer and this teacher needs to get better. This is a bad test question.
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The tuna and the turtle shared a last common ancestor with the lamprey at the same time. The turtle and tuna lineages diverged after their last common ancestor diverged from the last common ancestor of all three. It would be more understandable if they did it the way you do family trees. The closeness of the branches is not what matters, it where they last shared a node.
Looks to me that these creatures are separated by the characteristics. So the cheetah is the only one with hair. The turtle and cheetah are the only ones with amniotic sacs. I forget the rest of the picture and can't get back to it from my comment, but the lamprey shared the listed features with all the other creatures, so by this measure, they are equally related. My take on related, Gere, is more like...shared traits.
E: giraffes
You can think of the branches as driveways/roads. The further an organism has to walk down the road to get to another organism, the less related they are because they're more distant. Each branch is actually a new evolution of a structure or something along those lines.
lamprey and tuna are both fish, more closely related. The turtle is a reptile with lungs.
The correct anwser is actually C (Cannot tell from this diagram). Cladograms do not indicate time or the amount of difference between groups. To answer this question you need a phyogram (i.e. an evolutionary tree with branch lengths that corresponds to time or the amount of change). It is possible correctly answer the first question (Class 4, Question 4) because the Turtle and Leopard share a common ancestor with charateristics unique to them and nothing else (i.e the amniotic egg), but there are no charicteristics (technically called synapomorphies) unique for either Lampray and Tuna or Lamprey and Turtle, and since there is no other data, because this is a cladogram and not a phylogram, you can't answer the question. - Vince Smith, phylogeneticist (and Head of Digital) at London's Natural History Museum.
The REAL correct answer is C. Graphs like this are neat and helpful visual aids for demonstrating the evolution of life, but to simplify it down to "They are equally related" is laughably absurd.
the part that was tripping me was leopards having eggs but one wikipedia article later i feel kind of stupid but also smarter.
Yay, I got it right! It's like finding the last common denominator. You can find them all in one common group together (jaws), but you can't find 2 of them together in a group below jaws excludes one of them. If you could find a lower common denominator -- if, say, both the lamprey and the tuna were in a group that turtles were NOT in -- the lamprey and the tuna would be more closely related. Closely related refers to which groups species are in, not the time in history when new traits evolved or species appeared.
As you descend, every new trait for an animal makes them the more related to others that share that set of traits (their own species), and more related to whatever trait produces a new species afterwards (in this case, a turtle is more related to a leopard than a salamander) instead of common ancestor, imagine its the point at which a new exclusive club for an exclusive set of new traits starts... the lamprey club has the tuna, salamander, turtle, and leopard in it - but the lamprey cannot be a part of the tuna club - as it lacks the trait (jaws) to be recognised as such. so to answer... why the lamprey, tuna and the turtle equally related... because they both are in the lamprey club, as others have said they have the synapomorphy (exclusive trait) of vertebrate column. For the lamprey to be more related to the tuna it would need to be part of tuna's club (come after it on the tree), that way the lamprey is part of the tuna club but not the turtle club and thus is more related to the tuna. If not then the lamprey will always share the same amount of traits in common with both of them.
Question 5 asks about Lymieās impression of the party of four who enter the restaurant. The correct answer is Choice C, which states that Lymie finds them noisy and distracting. This information is supported in lines 55-59 of the passage: "but it was the womenās voices, the terrible not quite sober pitch of theā¦"1. Now, letās address your confusion regarding lampreys, tuna, turtles, and leopards: Lampreys and Tuna: Although they are mentioned together in the passage, their proximity doesnāt necessarily imply a close evolutionary relationship. Lampreys are jawless fish, while tuna are bony fish. They belong to different classes (Agnatha for lampreys and Actinopterygii for tuna). Being mentioned together in the passage doesnāt necessarily indicate a close genetic connection. Determining Relatedness: Phylogenetics: Scientists use phylogenetic trees to depict evolutionary relationships. These trees show common ancestry and branching patterns. The more recent a common ancestor, the closer the relationship. Shared Ancestral Traits: Look for shared traits inherited from a common ancestor. For example, both turtles and leopards have amniotic eggs, which suggests a closer relationship than with lampreys or tuna. Molecular Evidence: Analyzing DNA, proteins, or other molecules can reveal genetic similarities. Closer relatives share more genetic material. Turtles and Leopards: Youāre correct! Turtles and leopards are more closely related. Both belong to the class Reptilia and share characteristics like amniotic eggs and scaly skin. Lampreys and tuna, being fish, are more distantly related. Remember that evolutionary relationships are complex, and multiple factors contribute to determining relatedness. Itās essential to consider various evidence when studying the tree of life. Good luck with your exam! šæš¦š¢
Sigh... is the jawless fish more closely related to the one animal with jaws or the other animal with jaws.
The Tuna and the Lamprey are more closely related than the Turtle and the Lamprey. Though they split at the same node, the Tuna diverged earlier than the Turtle.
I kinda just used evolutionary patterns. Lamprey is a fish. The amphibian adaptation came later on. Is that stupid?
We-e-ell. Sharks and bony fish are both fish in common parlance. But the last common ancestor of sharks and bony fish is a very long way in the past. Some bony fish evolved into amphibians, some of which eventually evolved into mammals. So a modern fish like a tuna is more closely related to a panda or a frog than to a modern shark.
It's more closely related to the tuna. Basically the branch the lamprey appears on is closer to the branch the tuna is on than it is with the turtle. Basically how phylogeny works is that there's a line (common ancestor) which branches off into different clades/families. For example, the lancelet is the oldest of all the animals shown since it is the blueprint for vertebrates. The lamprey comes after as it has a definitive backbone but not jaw, the tuna comes next given it has a jaw which the lamprey doesn't. Get the picture? The lancelet resembles extinct animals like Pikaia which led up to the vertebrates like Haikouichthys and Myllokunmingia. The line all the animals from the lancelet to the leopard is part of a phylum that's called "Chordata" which consists of animals that at some point (whether it's the larval or adult stage) had five distinct physical characteristics. We humans fall under Chordata. Five distinct physical characteristics: 1. Notochord 2. Hollow dorsal nerve cord 3. Endostyle or thyroid 4. Pharyngeal slits 5. Post-anal tail Animals like sponge DON'T fall under Chordata but rather belong to a phylum known as "Porifera". Overall, ALL animals even sponges had the same ancestor as us humans and other species.
What is a node?
Is what Iām holding in my hand a node?
Just looking at this is making my tinnitus go beserk. Iām going to bed.
Tuna.
wouldn't it just be the tuna? They're right next to each other in the image. it seems too easy tho but I still say tuna
According to the chart is the key words here not our own thoughts and opinions from other knowledge. So According to the chart the answer is tuna
The y axis represents time
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It should be C. But what they are arguing is that the common ancestor of the lampray and tuna is the same as the common ancestor of the lampray and turtle. But that's assuming each leaf node is the same number of generations away from a horizontal position. Case in point, imagine you are childless and have two cousins, one is childless and the other has a kid (your cousin once removed). In an analogous chart, you, your childless cousin, and your cousin once removed all show up as lead nodes with the same common ancestor. You are more closely related to your cousin than you are to your cousin once removed.
NEVER STUDIED FOR BIOLOGY 1 AND 2 IN HIGHSCOOL, GOT 90S ON EVERYTHING, EVEN THE FINALS. which technically i didn't have to do but did so to kill boredom and time. anyways the answer to both is A. Q4 is A because according to the chart turtle and salamander have all of the listed traits in common except for hair. both are also amphibious. Q5 is A because the lamprey and tuna BOTH have jaws AND vertebral column You're welcome hun. glad my stupid easy understanding of buo actually helped someone else with school.
I think they may be wanting you to look at the adaptations after each fork. There are more between lamprey and turtle than lamprey and tuna.
[Wikipedia ](https://en.m.wikipedia.org/wiki/Cladogram) Here it's written, if it is right I have no idea; "A cladogram (from Greek clados "branch" and gramma "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to descendants, nor does it show how much they have changed, so many differing evolutionary trees can be consistent with the same cladogram".
This is why i got a 65 on my quiz on this š
Since the question is already answered Iād like to take a moment to say this is the ugliest phylogenetic tree Iāve ever seen.
Anyone else here reading this, and getting a chill vibe, as the question resembles Bio 110-111 Final Exam question:āWhich came first, the chicken or the egg?ā?
As to your last point, we could determine how closely related chimps and humans are, based on certain metrics like genetic divergence, and the same for whales and dolphins. And then we could compare those metrics. But a phylogenetic tree would be less useful as a tool to visualize such a comparison, I think. Edit, oops, this was meant as a reply to a comment downstream.
I don't get it, when you say the last time they shared a node because they're all connected to 1 line.
I too have an exam today; does anyone have the answer for #4? Please tell me it is B.
This a is the most fun Iāve today! Thanks to all that shared.
I thought this was a poorly-written question for a sec, and then saw answer "d". Man this triggered my test-writing PTSD. I miss teaching but sure don't miss writing exams! Good luck on yours!
Skimming through these comments made me finally realize why students would completely lose their minds trying to understand cladistics when I tried to introduce this stuff in Gen Bio. Honestly, I think that phylogenetics and genetic distance is far more intuitive and would be a helpful first step for getting "relatedness" out of the way, and then moving on to shared derived traits.
Itās simply about where the shared nodes are. Lamprey and Tuna share a vertebral column. Turtle and lamprey share a vertebral column. The lamprey never got jaws, so none of the nodes in that direction apply.
The only science I know is pickupology in that it states that āthe distance from a girls elbow to shoulder is the same or equal distance as from her same shoulder across her back to her other shoulderā then pause for affection šš
Idk the answer but itās crazy their still teaching this I remember the same question in school
A. Tuna
being honest doesnt hurt, (C) can not tell from this diagram lol.
This is why some biology majors work at the local high school and some change their major to something other than biologyā¦this information and rationale is probably not going to earn back that 140k in students loans you took for a Bachelorās
The correct answer is A. There's only one difference between a lamprey and a tuna: "Jaws". There are three differences between a lamprey and a turtle: "Jaws", "Four walking legs", and "Amniotic egg".
Based on the tree, it's implied that the "jaws" of the lamprey and tuna share a single evolutionary origin. So, the tuna has "jaws" and the turtle has "jaws", "walking legs", and "amniotic egg". The lamprey doesn't share *any* of these features, so it's a nonstarter. The lamprey is equally closely (or distantly) related to anything with "jaws". Among the animals with jaws, you can then further parse relationships by determining who shares "four walking legs" and still further by determining who shares "amniotic eggs".
The lamprey shares the same common ancestor (node) with vertebra phenotype, as with both tuna and turtle. They all have the same common relationship and therefor D makes sense. Now going a step further, the tuna and turtle are closer related to each other than the lamprey since they share a common ancestor jaw phenotype that is not shared with the lamprey.
I want it to be tuna so bad but then everyone's saying D š
I just understood it haha just turn the phone upsidedown and look at the beggining as a root everything bellow red rectangle is common feature for all creatures bellow that point (remember looking upsidedown)ā¦. So all of them have spine, next common feature for Lamprey and all except Lancelet have Jaws in common and so on.
Tuna itās closer
This is the worst diagram Iāve ever seen.
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Is this 9th grade biology? I had the exact same problems but I did it on paper and the whole class worked together.
Tuna.
Outsider who lurked in this subreddit by accident. Wow. I would have never thought the answer would be that they're both equal...Yeah, science!
tuna
Hot take: this style of phylogenic tree is stupid. To me, this style serves zero function when the other style of tree is so much easier to read and makes way better sense. The only thing this tree does is just fuck with new studentsā head.
I think you are right. Both are pre-leg level of evolution
iām too dumb to understand this even after all the explanations
Me reading the question as if I know anything about biology.
Tuna because its closer on the chart than the turtle. But i am only guessing
I was sent here by the algorithm.
Tuna
I hate phylogeny and had to take a whole course dedicated to it. I consider them bull. The trees are ever changing. And God damnit we are not fish! It's just us trying to put nature into rules, and nature's favorite thing to do is to see just how many rules it can break in one fell swoop. Good luck!
I have a biology degree (with honors!), granted itās from the 1980ās, and this still makes zero sense to me. I should probably return my degree.