Homologus
Trait
Monkey rib cage and human rib cage
1. A. I chose a monkey and a human for my homologus
traits. My primary focus is the rib cage. The humans and monkey rib cages are practically
the same in structure but shaped and curved a bit different. I
believe these two share the homolugus trait because of their skeletal system.
B. The homologus trait I chose of
both subjects are the skeletal system (like I described in part a) What I’m
focusing on is their similar rib cage. Humans have 12 ribs and monkeys have 13
ribs which both have the same function which is to protect, support and respiration.
It holds the lungs and heart and mainly protects the vital organs. Humans have
a barrel-shaped rib cage and
monkeys have a funnel-shaped rib cage, meaning humans rib cages are more round
and not flat and monkeys have a flat chest. I think that these traits exhibit
differences because of their different posture. Monkeys can walk on all four
which has made them slouch or have a hunch back type body when humans just walk
on two feet.
C. The closest ancestor to share
similar traits to a human and monkey
would be the homo antecessor. The homo antecessor goes back millions of years
ago and have the same or similar body structure of a human and monkey. Which
they also share similar genes/dna. They have the same skeletal system and its
more similar t the human body than monkey.
Analogous Trait
1. A.
The analogous traits ive chosen is the hand of a human and a the fin on a
dolphin. They have different structures but practically the same bones needed
for use. They both have phalanges, metacarpal, ulnas, and radius and humerus
bones. Both have full function but with different bony structure that they both
use on the daily.
B. The analogous trait of both
species is the hand/fin. Like I said before the structures are completely
different but serve the same purpose. They could both radiate up and down, side
to side. Unlike humans dolphins can’t grab things or make a fist. Their structure
is straight and humans have more range of motion. The fin is actually smaller
but has 5 phalanges like the humans. Human’s humerus bones are longer than
dolphins as well. The main point is that they both have similarities to the
skeletal system (hand/fin). Primarily they both have the same bones needed to
complete the structure but are different in size and shape and function or capabilities.
C. I believe that
the ancestor for both the humans and dolphins could of shared the same traits.
What I researched was that the mesonix has the same body structure of a dolphin
which this animal goes back millions of years ago. Only thing was that this
animal was on ground rather than water but they would spend most of their time
by water and getting into the water. Their limbs then got smaller and attached
more to the body which made it perfect for underwater movement. I think that
these traits are analogous and not from common descent because humans evolved
to walk upright and to use hand for many things when dolphins evolved to be in
water and swim using their fins/back to move and have less functions on their
fins.
That's so funny! I also chose a monkey and a human for my homologous trait! Isn't it so cool how we relate?! And for our analogous trait, I had absolutely no idea that dolphins and humans have the same skeletal system when it comes to our hands and their fins! That was way cool to read and I even had to show this to my friend! Thanks for posting!
ReplyDeleteah nice! I thought it was probably the easiest to do some research and find answers to! But yeah i thought that was pretty amazing how they have the same skeletal system when it came to that body part! I also shared with some of my friends! It is awesome though!
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ReplyDeleteOkay on your homologous trait. They are two differently shaped structures, though I am not sure that they demonstrate different functions. The differences aren't due to different functions but are the residual and incidental affects (as you note) from different modes of locomotion.
ReplyDeleteHomo antecessor is indeed an ancestor of modern humans but is it an ancestor of modern monkeys and apes? This is a little like saying that your father is the ancestor of both you and your cousin. He isn't. He's part of the same family tree but you have to go back farther to find your common ancestor with your cousin, namely a grandparent. That said, we do know that both monkeys and humans are primates and share a common primate ancestor with the ancestral rib cage structure, passed onto these two organisms. That demonstrates the genetic relationship.
Remember that an analogous trait arises due to similar selection pressures but not from genetic relatedness. Your example of a human and dolphin fin is just the opposite. It does share a common genetic ancestry, namely an archaic mammals with the ancestral limb structure, but changes have evolved due to environmental differences. Similarities are due to genetics and differences are due to the environments. That defines a homologous trait, not an analogous one.
Good images.
Thank you for your comment Mrs. Rodriguez! I do understand what your saying and I like how you made me understand it clearly! It was an interesting assignment and i probably need some work to fully understand it.
ReplyDeleteYou are welcome. Thank you for replying back.
DeleteI never knew that dolphins ands humans shared any similar traits before reading your post. When you look at their appearances from the outside you would never guess that they have the same functioning bones as one another. Also the fact that humans and dolphins developed both these traits separately is crazy to think since they literally have nothing in common but had to develop this structure for very different reasons which gets me to think how is it possible that very different animals with no common ancestor can still develop relatively similar traits. Great post!
ReplyDeleteI would like to give some constructive feedback with this comment, if you do not mind. For me, this post was pretty hard to follow because the responses to questions A, B, and C were all together. maybe if you put a line in between those responses, it would have been better.
ReplyDeleteOther than that, I love the fact that you were able to find one picture of both organisms unlike many other people who had to post 2 pictures for each homologous traits and analogous traits.