Isn't the opposable thumb a autapomorphy for the taxon Primates? Because it is a apomorphy which differentiates Primates from other taxons, or is the origin of the opposable on a other level/from an older ancestor?
it's all about what you're comparison group is, the terms are annoyingly relative. For example; opposable thumbs are apomorphic when comparing primates to the last common ancestor between primates and rodents. But if you compare humans and chimpanzees, the opposable thumbs of humans are plesiomorphic - the comparison group (chimps) has the character, so it's ancestral in humans. Loss of odorant receptor expression in humans is autapomorphic compared to chimpanzees (we express far fewer smell receptor types than chimps), it's a change from the ancestral condition. You need at least two ingroups for anything to be synapmorphic or symplesiomorphic, that's a good soundbyte to remember for exams.... i hope anyway, I'll be remembering it on my vertebrate zoology exam tomorrow 🥴
This is a good question--in this instance, I would still call it a synapomorphy, since there are many different species within primates that all share this trait. We tend to only use the word autapomorphy when it refers to a single species, though Order Primates is the only taxon of that particular level with an opposable thumb.
Hahahaha, I can definitely see where you are coming from. And yes, when speaking in more informal contexts, I do tend to use simpler words such as primitive instead of plesiomorphic, or derived instead of apomorphic. That said, there is still a utility to this more precise, if sometimes cumbersome, terminology. Use of specifically defined jargon allows us to communicate more precise meanings within our field, and that is how these terms are intended to be used. So we will talk about things such as how symplesiomorphy tends to make people surprised to uncover phylogenetic relationships. The use of sympleisomorphy specifically implies we are talking about similar traits that come from an old ancestor that were retained in multiple lineages, but not all. This is the reason why people were initially surprised to learn that humans are more related to chimpanzees, rather than chimpanzees and gorillas being more closely related to other. The reason they have a lot of overall morphological similarity is due to symplesiomorphy, chimpanzees and gorillas retained a lot of similar characteristics from the common ancestor all three of us (humans, chimps, and gorillas) all share. We're the odd ones of the bunch, that had a whole lot of evolution and just look much different.
A synapomorphy is something that is shared between two or more lineages (syn), and is relatively new (apo). An example is the opposable thumbs of primates, as this is a trait that all primates share. We comparing primates to other mammals, this is a relatively new trait, since other mammals don't have opposable thumbs. We use synapomorphies like this to help figure out who is closely related to each other. Does this help?
yeeeah you're literally saving my life with this high-quality format, thank you
you are really good in what your doing ma'am,
Zoology Exam coming up next week. Very helpful
Good luck! Glad I can help people outside of anthropology.
Thanks for the explanation . It helps a lot !
Glad to help!
Same
just want to learn something new. Thank you very much!
Glad you learned something new! Thank you for the lovely note.
Thank you, this was really helpful before my biology test!
I am so glad to hear this! Thank you so much for your kind comment.
Love your wall!
Thank you! I had a lot of fun setting up my virtual classroom.
Isn't the opposable thumb a autapomorphy for the taxon Primates? Because it is a apomorphy which differentiates Primates from other taxons, or is the origin of the opposable on a other level/from an older ancestor?
it's all about what you're comparison group is, the terms are annoyingly relative. For example; opposable thumbs are apomorphic when comparing primates to the last common ancestor between primates and rodents. But if you compare humans and chimpanzees, the opposable thumbs of humans are plesiomorphic - the comparison group (chimps) has the character, so it's ancestral in humans.
Loss of odorant receptor expression in humans is autapomorphic compared to chimpanzees (we express far fewer smell receptor types than chimps), it's a change from the ancestral condition. You need at least two ingroups for anything to be synapmorphic or symplesiomorphic, that's a good soundbyte to remember for exams.... i hope anyway, I'll be remembering it on my vertebrate zoology exam tomorrow 🥴
This is a good question--in this instance, I would still call it a synapomorphy, since there are many different species within primates that all share this trait. We tend to only use the word autapomorphy when it refers to a single species, though Order Primates is the only taxon of that particular level with an opposable thumb.
I feel like simpler, more unique words could be used to define each term.
Hahahaha, I can definitely see where you are coming from. And yes, when speaking in more informal contexts, I do tend to use simpler words such as primitive instead of plesiomorphic, or derived instead of apomorphic.
That said, there is still a utility to this more precise, if sometimes cumbersome, terminology. Use of specifically defined jargon allows us to communicate more precise meanings within our field, and that is how these terms are intended to be used. So we will talk about things such as how symplesiomorphy tends to make people surprised to uncover phylogenetic relationships. The use of sympleisomorphy specifically implies we are talking about similar traits that come from an old ancestor that were retained in multiple lineages, but not all. This is the reason why people were initially surprised to learn that humans are more related to chimpanzees, rather than chimpanzees and gorillas being more closely related to other. The reason they have a lot of overall morphological similarity is due to symplesiomorphy, chimpanzees and gorillas retained a lot of similar characteristics from the common ancestor all three of us (humans, chimps, and gorillas) all share. We're the odd ones of the bunch, that had a whole lot of evolution and just look much different.
I still can't understand what synapomorphy is? :(
A synapomorphy is something that is shared between two or more lineages (syn), and is relatively new (apo). An example is the opposable thumbs of primates, as this is a trait that all primates share. We comparing primates to other mammals, this is a relatively new trait, since other mammals don't have opposable thumbs. We use synapomorphies like this to help figure out who is closely related to each other.
Does this help?
I donot know these concepts, honestly speaking 🥸🥸😊😜🙏🙏🙏
can you be my professor instead??
Aww, that's sweet. I mean, if you want to come to Brooklyn College you're more than welcome to register for my classes!