Thursday, February 23, 2012

Homology and Analogy


The Loxodonta (African elephants) and Elephas (Asian elephants) both have a proboscis (an elongated appendage from their head – their trunk).  

The difference between the African and Asian Elephant trunks is that the African trunk has two ‘fingers’ at the snout while the Asian trunk only has one. This is most likely due to geographical differences.

Both species being a part of the Elephantidae family, they diverged from a common ancestor of the Mammutidae, which includes species termed as mastodons.

 African Elephant

Asian Elephant

 African Trunk

Asian Trunk


The Elephantidae and the Tapir both have a proboscis. A tapir is a large browsing mammal, similar to a pig’s shape, with short legs and a snout for grabbing or holding.

The tapir uses it’s just the same as an elephant. The tapir’s snout is highly flexible, able to move in all directions, and allows it to grab food that would otherwise be out of reach. The Elephants trunk is similarly famous for this. These two animals don’t seem to have a common ancestor as the elephants (proboscidea) and tapirs (perissodactyla) order seem too dissimilar.

Elephant

Tapir

3 comments:

  1. Great trait comparisons on both.

    You never identified clearly which was the homologs and which were the analogs. I'm guessing correctly, I think, but in the future, don't make me guess!

    Good job discussing the ancestor issue of the homologous traits, but since both the tapir and the elephant are mammals, won't they have a common ancestor at some point? This issue is whether the common ancestor had a trunk-like proboscis that it passed onto to both descent lines. The word "seem" worries me a little. Appearances can be very misleading, as this assignment was meant to demonstrate.

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  2. I think you did a great job with the trait comparisons. your both reminds me that this is an anthro class!! it was very informative and helped me understand a cuple things a little more.
    chaschatman

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  3. I really enjoyed your post it was extremely interesting! I was really surprised to learn that elephants and tapirs don't have a similar ancestor. They look very similar and use the similar appearing trait for the same reasons. I think somewhere down the line, both the tapir and the elephant do share a common ancestor since they are mammals. Everything originates from something!

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