1. Homologus
Traits: Echidna and platypuses are both
mammals that are able to lay eggs.
a. Echidnas
are monotremes mammals that lay eggs.
They are covered with coarse hair and spines. Their mouth and nose is elongated and
slender. Echidnas have short strong
limbs with large claws. Like an
anteater, they feed by tearing open soft logs and use a sticky tongue to collect their prey.
The platypus is a
wooly, furry coat mammal that is a species of monotremes. They have a bill and webbed feet like a duck,
a tail like a beaver, and their body and fur is like that of an otter. Platypuses hunt underwater, where they use
their webbed feet and tail to swim. They
have folds of skin that cover their eyes and ears to prevent water from
entering.
b. Monotremes
are mammals that that lay eggs like reptiles and birds. Echidnas lay a single
soft shelled leathery egg. It deposits
directly into her pouch. The egg hatches
after 10 days. The platypus lays one to
three eggs. The eggs are small and
leathery. The mother keeps them warm by
holding them between her body and her tail.
They hatch in about ten days. These
differences are minor yet very specific because of the amount and the placement
of the eggs.
The platypus has both
ovaries but only the left ovary is functional.
The echidna has two functional ovaries.
c.
The common ancestor of these two species
is the Steropodon. They lived alongside dinosaurs
and early mammals. They were a small
mammal with short limbs and would have been an egg-layer. Due to the fossils found the scientists have
theorized that the Steropodons were mammals that laid eggs.
2. Analogous
Traits: A duck (bird) and a platypus (mammal) both lay eggs.
a. A
duck is a bird that lays eggs. Ducks
usually have elongated and b road bodies.
They have bills which contain serrated lamellae. Ducks have scaled legs and web feet. They also have very strong wings.
b. Ducks
and platypuses both lay eggs. Their
cloaca is the exit for the urinary, reproductive, and excretory systems.
c. There
is no known common ancestor between the platypus and the duck. However, both of their ancestors have the
trait of laying eggs.
DISCLAIMER:
Not sure why the second paragraph posted the way it did. Everything else pasted properly. Hmmmmm inquiring minds wanna know!
I really like how you used the trait of laying eggs for both your analogous and homologous example. Although these animals all posses many of the same traits, such as way of reproducing, style of their beak and body shape, as well as the terrain of which they reside, they are not all considered to be of the same species. Although their are many different species which use laying eggs as their form of reproduction, I never really stepped back to think about the origin of the species itself. Very interesting blog post! Thanks for sharing!
ReplyDeleteI enjoyed your blog and felt it was an very informative read. I appreciate the detailed gestational description above and beyond the easier description of they both lay eggs. i felt your descriptions were well thought out and complete.
ReplyDeleteMSAbloggin13,
ReplyDeleteThanks for taking the time to read the blog. I was intrigued with the animals I chose and I enjoyed looking them up. The fact that these animals are so similar and yet are so far apart in the world of evolution fascinated me.
Very interesting example of a homologous trait! Very creative. Good description on the differences but can you speculate on why those differences exist? What environmental pressures resulted in these differences evolving and the two organisms diverging in their egg production styles? Good work on their ancestry.
ReplyDeleteI like how you used the same trait for both examples. It helps highlight the differences between homologous and analogous traits.
The only caution is that all organisms share a common ancestor if you go back far enough. Birds and mammals both branched off of reptiles some 65 million years ago, so the common ancestor between the two was likely a reptile. That leads to a quandry here. Many reptiles lay eggs. So did birds inherit this trait directly from their reptilian ancestors? Regardless, we do know that the ability to lay eggs in the platypus arose independently long after mammals branched off from reptiles, so this is a case of parallel evolution and these are analogs.
I liked the trait you used for the animals. I also thought it was smart to use the same trait for both homologous and analogous showing their differences. I didn't know that mammals laid eggs either. I found that interesting.
ReplyDeleteWow I had never even heard of an enchidna prior to reading your blog post and I found it interesting that it has a pouch because I had only associated that characteristic with marsupials like kangaroos. The platypus probably has several traits from different species in order to increase it's survival in different environments. Great post!
ReplyDeleteThank you very much kimboslice. I happy to hear you not only enjoyed it, but got something out of my post. We don't always take the time to learn new things but when we do I get a lot of enjoyment out of it.
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