Homologus Trait :Webbed Feet of Sea Otters and
Beavers
a. Two different species that possess the
homologus trait webbed feet are sea otters (Enhydra lutris) and beavers (Castor canadensis). Both mammals use their webbed feet to help
them swim. Sea otters can be found along the coasts of
the Pacific Ocean in North America and Asia. The sea otter is a carnivore and
spends most of its time in the water but, in some locations, comes ashore to
sleep or rest. Sea otters have webbed feet , water-repellent fur to keep them
dry and warm, and nostrils and ears that close in the water. Beavers are
herbivores and are typically found in the forests of North America, Europe, and
Asia. These large rodents waddle on land but are graceful in the water, where
they use their large, webbed rear feet like swimming fins.
b. Both
sea otters and beavers use their webbed feet trait in different ways. Both
posses the trait for webbed feet, however all four of the paws on a sea otter
are webbed where as on a beaver, only the two rear paws are webbed. Sea otters spend most of their time in the
water floating and swimming on their backs, their webbed feet enable them to
swim fast, helping them avoid predators. Beavers exhibit only two webbed feet,
their front two paws are similar to the human hand in that they have finger
like paws, which enable them to build damns and gather food. Their webbed feet,
like the sea otters allow beavers to swim from predators,
their rear webbed feet allow beavers to swim at speeds of up to five miles an
hour.
c. Although
both species are similar in the way that they look , one might think the two
species are closely associated. However, they are not related, sea otters
belong to the weasel family and beavers belong to the rodent family. The sea
otter and the beaver could both be linked to the platypus, which has webbed
feet as well. The platypus stems from the North American Ptilodus which is part
of the Multituberculates who first appeared in the Jurassic, and went extinct
in the early Oligocene, with the appearance of true rodents. Over 200 species
are known, some as small as the tiniest of mice to the largest the size of
beavers.
d.
| Sea Otter |
| Beaver |
Links to more
information:
Analogous Trait
for Webbed Feet:
a. Two different species that posses the
analogous trait for webbed feet are the Mallard Duck (Anas platyrhynchos) and the Northern Leopard Frog (Rana pipiens). Both species have this trait, however
they differ immensely. The green head and yellow bill of the mallard duck is a
familiar sight to many people living in the Northern hemisphere. In fact, the
mallard is thought to be the most abundant and wide-ranging duck on Earth. The
mallard is an omnivore
Once the most abundant and
widespread frog species in North America, leopard frogs were widely collected
not only for dissection but for the food industry (frog legs) as well. The
northern leopard frog is carnivorous.
b. Both the mallard duck and the
northern leopard frog have webbed feet
similar in that all their toes are connected, there is no separation
between two or more digits of the feet. Both the mallard duck and the northern
leopard frog’s feet look and act very similarly, helping both species not only
to walk but also to swim as well. The two rear feet on the northern leopard are
much more connected then its front to feet enabling the frog to swim much
faster and fluid, and the mallard duck on has two feet, both of which have
webbed toes. Which helps the duck to swim more efficiently as well.
c. The common ancestor to both of
these animals is a type of reptile, possibly the Icthhyostega, which is the
earliest reptile, I have been able to trace back to both frogs and birds.
d.
| Mallard Duck |
| Northern Leopard Frog |
Links to more
information:
Both of your examples here are analogs. Keep in minds that analogous traits have similarity in structure/function but no common ancestry. That describes both sets of traits you have presented here. You presented them well, but you are missing a homologous set of traits. Homologs have common ancestry and distinct differences in the traits that demonstrate evidence of divergent evolution to different environmental conditions.
ReplyDeleteMake sure you review these concepts and read other student posts so you understand the differences between the two types of traits.
One other note: Your images did not come through. I've checked in three different browsers and they are not visible in any of them. Make sure you check your post after you publish to see if it posted as you wanted it to.
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