1. Black bears and Pandas are very similar animals,
both share the homologous trait of fur and a closely resembled body structure,
but have a difference in paw structure.
b. Black bears have paws that are sharpened at the
end with five fingers. The black bears diet consists of many different types of
foods from insects, fish, fruit, and small mammals. Black bears are also
extremely hungry animals because of their choice of food within their diet it
is likely that black bears developed sharper claws than pandas so they can
gather their food. The panda bear has a paw with 6 fingers extending from it
with less sharpened claws than the black bear. This 6th finger is
called the radial sesamoid. The radial sesamoid was likely to develop since
panda bears have a strict diet of only bamboo. The radial sesamoid acts as a
thumb and allows the panda to grasp the bamboo. Although both animals have a
very similar paw structure there is a slight difference to both of them.
c. It is likely that both animals may have descended
from early dog like creatures. They share the resemblance of dogs in some ways
such as their paws and their facial structure is a bit similar.
2. Dolphins and beavers are two animals that both
have tails. However the use of their tails is vastly different.
b. Dolphins use their tails to swim and maneuver themselves
while they are underwater. Beavers use their tails to help build shelters or dams.
While both of these animals have tails the uses for them are extremely
different. The dolphin is a primarily aquatic animal, while the beaver is only
a semi aquatic animal. Both share an aquatic habitat and have a similar
structure to them, however it is used differently. The beaver’s tail does not
provide much aid in swimming since it has webbed feet however the dolphin
relies on its tail to maneuver underwater. Both animals have a tail bone as
well.
c. It is possible that the dolphin and the beaver
could be traced back to a common ancestor. Both animals live in aquatic environments
and are mammals that breathe. The beaver may have came from the same ancestor
as the dolphin but managed to evolve over time and adapt to a lifestyle
partially on land.
Hello!
ReplyDeleteFirst off, I love all the information you gave! It was very informative and really helped explain the function of the traits that you were focusing on. Giving very specific examples of how they are used helped me understand how these animals use their traits to survive! The pictures are good, however, they don't showcase the traits very much. Maybe getting pictures that are more specific to the traits would help show the structure of them and make the text easier to understand. Good post!
While I see that the paw structure is similar, I'm trying to figure out how the thumb fits in. The panda's thumb is a derived structure. It is analogous to one of the bones in the bear's wrist, so it depends upon how you are comparing it. The "hand" structure as a whole could be argued to be homologous structures but you are doing it using analogous traits. I'll go with it, but you need to understand the distinction here.
ReplyDeleteWe don't need to get too specific on ancestors. Both organisms are mammals and share a common mammalian ancestor that did possess this ancestral "hand" or "paw" structure.
Regarding your analogous trait: Remember that analogs must not share a common ancestry. Beavers and dolphins do have distinctly different tails, but they share a common mammalian ancestor that did posses an ancestral tail structure, as do most mammals. With that genetic ancestry for this trait, with distinct structural/functional differences arising from different environmental pressures, that makes this a perfect example of a homologous trait, not analogous.
Good images.
Thank you for your response Professor, i am a bit confused on this topic and will need to review it more. Are you saying that i had my examples for homologous traits and analogous traits backwards ? Is the reason my analogous trait not a well example because dolphins and beavers are both mammals ? If i were to compare an animal in the reptile class with a tail to that of one in the mammal class that would be an example of an analogous trait ?
DeleteNo, your homologous trait was fine, but I wanted you to see that if you had approached that section from a slightly different perspective (just from the thumb/sesamoid bone itself), it would have been an analogous comparison. By comparing the whole hand, it was a homologous comparison. Yes, tiny distinction, but an important one. Let me know if you still need clarification on that.
DeleteYour analogous trait was indeed a homologous one in actuality. It had the common genetic origin and the different functions/structure resulting from environmental differences. All characteristics of a homologous pair.
Thank you for the response.
I learned some things I did not previously know about the panda and the black bear reading your post. Thank you for sharing.
ReplyDelete