Showing posts with label Whale Evolution. Show all posts
Showing posts with label Whale Evolution. Show all posts

Sunday, October 21, 2012

Antlers Vs. Horns, Part 1: Antlers

Antlers and horns often look the same, but underneath, they are actually quite different!  Today we are going to look at not only what defines both antlers and horns, but also take a look at some of the animals that have each of them!  All aboard!

Let's start off with antlers.  As defined by the Google dictionary thing, an antler is "One of the branched horns on the head of an adult (usually male) deer, which are made of bone and are grown and cast off annually."  Something that I would like to add is that antlers are unique to the family Cervidae, which includes:
  • Deer
  • Elk
  • Moose
  • Caribou (Reindeer)
The only member of the family Cervidae that has horns on both the males and the females is the caribou, frequently referred to as the "reindeer."  However, it has been documented, on numerous occasions, for fertile females from other species of the cervids to occasionally grow antlers, but this is typically due to unusually high testosterone levels. 

The family Cervidae is one of the many families in the order Artiodactyla, frequently referred to as the "Even-Toed Ungulates" (so called because they either stand on two or four toes).  There are around 220 extant (still living, as opposed to extinct) species of artiodactyl, and included within this order are many familiar groups.  These groups, broken down by family, include:
  • Camelidae (Camels and llamas)
  • Suidae (Pigs)
  • Tayassuidae (Peccaries, a close relative of pigs)
  • Hippopotamidae (Hippopotamus)
  • Tragulidae (Chevrotains, a type of small deer)
  • Antilocapridae (Pronghorn)
  • Giraffidae (Giraffe and okapi)
  • Moschidae (Musk deer)
  • Cervidae (Deer)
  • Bovidae (Cattle, sheep, goats, antelope)
(Interestingly, the whales, dolphins, and porpoises should be included within the order Artiodactyla, but instead they have been placed within their own, separate order, Cetacea.  This area of the family tree is still messy, and a possible merging of the two orders, Artiodactyla and Cetacea, is being considered, which would create the order Cetartiodactyla.)

Also included within the order Artiodactyla is the extinct family Entelodontidae.  Later today, we will finally be getting around to what was supposed to be the monthly "What Is It?" challenge, but has turned into more of a quarterly or tri-monthly event!  Anyways, we will be announcing the winners of THE LAST CHALLENGE later this evening, after we look at horns!

Wednesday, August 8, 2012

Top Ten: Extinct Sea Monsters (Part 1 of 5)

Since ya'll kinda get gypped on Wednesdays with the "What Is It?" challenge, I decided that, when I do do the challenge, I will also include a "Top Ten" list.  I mean, come on now, who doesn't like lists?  I know some of my friends would be absolutely and completely lost without them!  So for today's "Top Ten," we are going to take a look at some of the world's most amazing, extinct sea monsters.  This is also up for debate, so if you disagree, just give me a holler!  Also, they are not in any particular order, I just kind of threw them all in there!  So without further ado, here we go, with our "Top Ten:  Extinct Sea Monsters!"

1.  Megalodon - This gigantic relative of the extant great white shark was thought to be simply massive: perhaps even sixty feet in length!  Living the world over, Megalodon stalked the seas during the Miocene and Pliocene Epochs, and only died out during the current Pleistocene Epoch, around two million years ago.  It is thought that Megalodon evolved to such gigantic proportions in order to be able to attack the massive whales that had started to evolve in the cooler seas of the Miocene and Pliocene.  Remember now: if it's a shark, then it's a fish!
A tooth fragment from Megalodon at this excellent restaurant called The Crab Shack on Tybee Island off of the coast of Savannah, Georgia. 
2.  Basilosaurus - A massive, predatory whale (and, therefore, a mammal) that cruised the seas in the Late Eocene Epoch, 40 to 34 MYA, fossil discoveries of this massive animal were reportedly so common in the southern United States during the early 19th century, that bones of Basilosaurus would be used as furniture!  It was first discovered in Louisiana, and is the state fossil of both Mississippi and Alabama.  Basilosaurus has also been found in Egypt and Pakistan.  At around sixty feet in length, the same estimated length of Megalodon, Basilosaurus is thought to have been the biggest creature alive at the time.

COMING UP:

3.  Liopleurodon
4.  Shonisaurus
5. Elasmosaurus
6.  Dunkleosteus
7.  Archelon
8.  Leedsichthys
9.  Tanystropheus
10. Tylosaurus

This post is part of the "Top Ten: Extinct Sea Monsters" series.  For the rest of the posts in this series, click HERE

Wednesday, July 18, 2012

What Is It? The Weekly Challenge #2 Answer

 Hello again!  Thank you to our guessers for this week: surprisingly, one of you got it exactly right!  Congratulations to Kristie C., who guessed this weeks mystery animal 100% correct!  The correct animal was Pakicetus, an ancient ancestor of the cetaceans, or the whales, dolphins and porpoises.  Around 53 MYA, Pakicetus lived in a world that was gradually becoming what we see today.  At this time, what we now know as India was its own special island continent, moving steadily northwards until, eventually, India crashed into Asia.  This crash resulted in the largest mountains we have today, the Himalayas

However, 53 MYA, during the Eocene Epoch, India hadn't quite reached Asia, a small sea separating the two, the remains of the vast Tethys Ocean.  The Tethys Sea was high in saline, which is incredibly good for life.  Microscopic organisms like plankton flourished, sending reverberations up the food chain, all of the way to the fish, which exploded in numbers as well.  And on the shore of this Tethys Sea, in what today is Pakistan, stood Pakicetus

As Pakicetus watched the gread abundnace of fish in the waters, he began to take short fishing trips into the water.  Over millennia, as Pakicetus took more and more fishing trips, of longer and longer duration, adaptations that proved beneficial for hunting fish in the water occurred, like a more streamlined shape, most likely webbed feet, and nostrils placed further back on the head.  Over a few million years, Pakicetus evolved into another ancient whale, called Ambulocetus.

Check back in a few hours for your next "What Is It?" challenge?  I promise you, after the last two, this one should seem like a piece of cake!  See you all then!
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