1.
Two species that contain a homologous trait are humans
and monkeys. Humans have tailbones and
monkeys have tails, which are homologous of each other. The structure of the bone is similar, yet
humans have very small tails that do not have a function hence why it is called
the tailbone and monkeys do. This trait
exhibits differences between the two species as monkeys have visible tails that
have functions and humans do not. Humans
do not need the extra limb. Monkeys use their tails for many functions like
grabbing and holding on to things. I
would conclude that the common ancestor would be a primate that could be within
the Anthropoidia infraorder.
Monkey Tail:
Human Tailbone:
2.
Sharks and dolphins have an analogous set of
traits. They both have fins, yet sharks
originate from the fish family while dolphins are in the mammal family. The use
of the fin with both species is to help the animal swim. Both the fins of a shark and a dolphin protrude
from the body and have a similar structure of a flipper. Dolphins had to adapt to their environment in
order to survive. Dolphins and sharks do
not have a common recent ancestor. The
two species share from the same kingdom and phylum but have different
classes. The common ancestor could not
have possessed this analogous trait because the common ancestor was the
Vertebrata Ubphylum, but then the classes split mammals from reptiles,
amphibians, and fishes. The shark
developed the fins under the fish class, while dolphins developed the fin much
later on through adaptation. We know
these traits are analogous because dolphins do not have family history of
fins. Dolphins had to adapt to its
environment in order to survive.
Dolphin Fins:
Some information found other than
from the textbook at:
Images found on Google
This was a very interesting post. It's amazing to me that dolphins and sharks are not directly related, and that their fins are actually analogous traits. They seem so similar, I thought it obvious.
ReplyDeleteI think I just learned something more on dolphins! When I was thinking of what to write on, dolphins and sharks didn't cross my mind. For the monkey tail and the human tail bone comparison i thought it was pretty cool. It made me think why do humans have tail bone when it doesn't function as a tail to humans than it does for monkeys in particular.
ReplyDeleteHi Laura,
ReplyDeleteI really enjoyed reading your blog because I wanted to compare the monkey's tail with the human tailbone, but I was afraid it would not count as a proper trait because the human tailbone isn't visible. What is fascinating to me is that humans, chimpanzees, gorillas and the other members of the great ape family evolved from monkeys, yet none of the ape species has a visible tail. That means that between 25 million years ago and 8 million years ago, the tail became inessential, yet we still have the tailbone.
Laura, I enjoyed your post! Specially because for the homologous trait, we were really close as to what we choose, however, instead of monkeys I went for gorillas, which are pretty similar. Anyways I enjoyed your post! Thank you also discussing about sharks and dolphins, that ones was really interesting as well.
ReplyDeleteI always knew that dolphins and sharks were in a different class, but I always assumed that both species had obtained the ability to swim, via fins, early on in evolution. I didn't know that Dolphins had no family history of fins. I also like how you put the specific ancestor of both species, Vertebrata Ubphylum, in your post.
ReplyDeleteIn general, good description of your homologous pairing with a couple of clarifications. The human tail bone still functions as important muscle attachments, particularly in the perineum. We will likely never lose it altogether because of these necessary attachments. Also, recognize that not all monkeys have a prehensile tail. That is only the New World Monkeys. Lemurs and old world monkeys don't use their tails to grasp things.
ReplyDeleteWith regard to ancestry, it is correct that the common ancestor was an early primate, but the question is, did that early primate possess the tail. Since that is the generalized structure of not only most primates but also most mammals, the answer is yes. Why is this important to know to confirm homologous status of these traits?
Good discussion of your analogous traits.
Some clarification on the ancestry for the issue of analogy: The common ancestor of the shark and dolphin would be an early fish, who did indeed possess these general aquatic structures and even passed them onto early sharks (who are cartilagenous fish). So why aren't these structures homologous traits? For the very reason you state, that dolphins developed fins later as they split off from land mammals. Good.