Wednesday, December 29, 2010

Fossil of the Week


12/29/10 – Whale Blowhole

The 44-foot-long skeleton of a modern North Atlantic Right Whale (Eubalaena glacialis), known as Right Whale #2030,* hangs in the atrium above the Museum of the Earth’s Borg Warner Gallery, fully visible from the lobby and from outside the building through its surrounding glass windows. It is an iconic specimen, salvaged for the Museum by PRI staff when the whale washed ashore in late 1999 at Cape May, New Jersey.

The whale’s blowhole is not immediately obvious from many angles of observation in our Museum. From outside the glass windows, however, this view makes it quite clear. It is through this orifice that a whale exhales in a geyser of air, saltwater, mucus, and metabolic wastes – prompting “Thar she blows!” from many a whaler in the past. The blowhole, high on the whale’s forehead, is the equivalent (the homologue** in scientific terms) to our nostrils. Although it looks like a single hole in the photograph, there are actually two holes here, which are angled slightly away from each other, producing the distinctively V-shaped opening characteristic of in right whales. [Toothed whales, such as the sperm whale, have only one opening – both openings are present, but only one opens to the surface.] The advantage to the air-breathing whale in having its nose in such a location is to be able to breathe while mostly submerged in water.

The earliest known fossil “whales” are called archaeocetes, and they were probably at least partly terrestrial (they had hind limbs!). Archaeocetes had nostrils near the tip of the snout, like land mammals do, rather than a blowhole on the top of the head. Genetic evidence suggests that the closest living relatives to whales are members of the family Hippopotamidae, which includes the modern hippopotamus.

The blowhole is also involved in whale sounds and communication. Air sacs just below the blowhole are filled with air, which is released to produce sound as happens when air is released from a balloon. The whale’s trachea or windpipe connects to the blowhole just as ours connects to our nose, but unlike us, there is no connection to the esophagus. So the whale has no risk of food accidentally ending up in the animal's lungs; likewise a whale cannot breathe through its mouth like we and most other mammals can.

*For more about Right Whale #2030, see Fossil of the Week 12/15/10 – Whale Pelvis and Hindlimb, and 12/22/10 – Whale “Hands.

** Homologues are structure in two organisms that are alike or similar due to common ancestry.


Text by Paula Mikkelsen

Wednesday, December 22, 2010

Fossil of the Week


12/22/10 – Whale “Hands”

The 44-foot-long skeleton of a modern North Atlantic Right Whale (Eubalaena glacialis), known as Right Whale #2030,* hangs in the atrium above the Museum of the Earth’s Borg Warner Gallery, fully visible from the lobby and from outside the building through its surrounding glass windows. It is an iconic specimen, salvaged for the Museum by PRI staff when the whale washed ashore in late 1999 at Cape May, New Jersey.

The front flippers of the right whale are large, broad, and blunt. According to PRI’s director Warren Allmon in his book A Leviathan of our Own: the Tragic and Amazing Story of North Atlantic Right Whale #2030 (Paleontological Research Institution, © 2004), the flippers of this whale weighed more than 400 pounds (150 kilograms) each. As you can see in the photograph, the front flipper of the whale has five digits or fingers. Despite their vastly different size and function, the arrangement and the relative size and shape of the bones in the human hand and whale flipper are remarkably similar, and are evidence of a common evolutionary ancestor.

In the photograph, you can see the triangular shoulder blade (scapula) in the upper left, connected to the upper arm bone (humerus), connected in turn to the two parallel bones of the lower arm (radius and ulna). The five loosely floating bones that follow (mounted on a large piece of plastic in our whale) are the homologues** of our wrist bones (carpels). Notice that each finger has five bones instead of the four that you can count on your own hand. The distalmost four bones of each finger are equivalent to our finger bones (phalanges). But the fifth or basalmost bones of the fingers are homologous to the bones in the back of your hand (metacarpals) – this is identical to their position in our hands, but in humans is covered by the fleshy palm – the similarity is more clearly visible when one looks at the hand bones of a skeleton.

Although the bones of the whale’s flippers are real, calcified bones, they are apparently a little "spongier" and less stiff than those of most land animal. They merely serve as supports for the solid flipper, and do not have to support the animal.

*For more about Right Whale #2030, see Fossil of the Week 12/15/10 – Whale Pelvis and Hindlimb.

** Homologues are structure in two organisms that are alike or similar due to common ancestry.

Text by Paula Mikkelsen

Friday, December 17, 2010

This Weekend at the Museum...

Genetically Engineered Fish: Threats or Food?
with Craig Altier, Associate Professor, Cornell University
Saturday, December 18
Noon
at the Museum of the Earth
Ocean populations of fish are being rapidly depleted by over-fishing.  With the increase in the world’s human population, the need for stable fish production is acute.  One way to mitigate this problem is through the increased use of aquaculture, but this practice itself can have damaging environmental consequences.  In an attempt to produce farmed fish more efficiently, the Aquabounty company has created a genetically engineered salmon that grows at twice the rate of conventional salmon.  This company is presently seeking approval from the US Food and Drug Administration to market the fish as the first genetically modified animal to be used for food in the US.  This discussion will focus on the important societal and scientific issues inherent to such approval, including food safety, environmental, and animal welfare concerns.

Wednesday, December 15, 2010

Fossil of the Week



12/15/10 – The Hind Legs of a Whale

The 44-foot-long skeleton of a modern North Atlantic Right Whale (Eubalaena glacialis) hangs in the atrium above the Museum of the Earth’s Borg Warner Gallery, fully visible from the lobby and from outside the building through its surrounding glass windows. It is an iconic specimen, salvaged for the Museum by PRI staff when the whale washed ashore in late 1999 at Cape May, New Jersey.

Some of the most fascinating features of a whale are those clearly linking it as a mammal to its terrestrial ancestors. Perhaps the best example in this category is the vestigial pelvis and hind limbs. Shown here is the left pelvic bone, with the thick thigh bone or femur at the center in the photograph. According to PRI’s director Warren Allmon in his book A Leviathan of our Own: the Tragic and Amazing Story of North Atlantic Right Whale #2030 (Paleontological Research Institution, © 2004):

“The pelvis of a whale is an inherently fascinating structure because it is so clearly a vestige of evolutionary history, retained from the distant past when the whale’s ancestors had four legs and walked on dry land. Although fossils have been found that show that early whales did have external hind limbs, modern whales normally lack any such appendages, except as unusual “freak” occurrences. The “pelvic” bones of modern whales (which actually often include vestiges of the femur or thigh bone, and even the shin bone or tibia, as well as the pelvis or hips) are normally buried inside the flesh of the body, underneath the base of the tail. Although these bones are the site of attachment of several sets of muscles … they are clearly much reduced from their former size and function…”

“Almost everything we know about the pelvic bones of right whales is derived from the work of John Struthers M.D., who in 1880 published results of detailed dissections of at least 10 animals. The pelvic bones of #2030* consist of two bones, one from each side of the animal. Comparing these bones to the illustrations of Struthers … indicates that they represent the pelvic or hip bones and the femur, all fused together. Struthers’ work indicates that right whales are variable in the form of their pelvic bones; some are completely fused while others have the femur, and even the tibia, present as separate bones.”

Right Whale #2030 provides a striking visual display at the Museum of the Earth. It also illustrates two major themes of the Museum – evolution and conservation – in one unforgettable specimen.

*The number 2030 was assigned to this female right whale in Massachusetts Bay in June 1990 by the National Marine Fisheries Service. Subsequent sightings included the Bay of Fundy in 1994-1997 as well as several sightings off the southeastern U.S. in 1996. She became entangled in fishing gear in May 1999 and despite attempts to free her, she died off the New Jersey coast in October 1999.

Text by Paula Mikkelsen

Friday, December 10, 2010

Art at the Museum



Join us this weekend for the fifth annual Ithaca Fine Craft Show from 11 a.m. to 5 p.m. This invitational gallery show features unique crafts by twenty of the area's finest artists in the Borg Warner Gallery of the Museum.  Ceramics, Jewelry, Fiber, Wood and Photography will be available for viewing and purchase in a range of prices.  This year's artwork includes porcelain functional ceramics by Stacy Esslinger, photographs by Dede Hatch, Marc Freedman's distinctive wood sculpture, handmade bags by Diane Richards and the fine jewelry of Brooklyn based artist, Cassandra Jackson. A percentage of sales will go to support the Museum of the Earth. Entrance to the show is included with regular museum admission.

Wednesday, December 8, 2010

Fossil of the Week



12/8/10 – Bubble Snail with Borehole

This is a fossil “bubble snail,” so named because of its “involute” spire – the normally pointed tip of the snail shell is sunken into the top of the shell, so that all you see is the last whorl (the “body whorl”), creating a bubble-like shape with a dimple at the top. Bubble snails are members of several families of the gastropod order Cephalaspidea, which are very closely related to the shell-less sea slugs or nudibranchs. About 20 families of bubble snails are alive today. The word Cephalaspidea refers to the head shield – a shovel-shaped head that protects the opening of the shell and allows these snails to plow their way through soft sand.

This bubble snail is Abderospira leblanci, described by Katherine Palmer* in 1946 in the family Cylichnidae. It is from the Late Eocene Epoch (Jackson Group, Yazoo Formation) of Danville Landing, Louisiana. It is a paratype** specimen, described in Bulletins of American Paleontology no. 117, in a 560-page monograph entitled “The Mollusca of the Jackson Eocene of the Mississippi Embayment (Sabine River To the Alabama River).” The shell is only 4.5 mm in height (that’s 3/16ths of an inch).

The shell here is still filled with sand and tiny pebbles from the excavation, but another thing is really interesting. The round hole in the shell tells us how the snail died! This hole was created by another snail – probably a moon snail (family Naticidae) or a rock snail (family Muricidae) – that attacked, bored, and ate the bubble snail. The beveled sides of the hole reveal this kind predator, as opposed to other mollusks that drill (for instance, octopuses drill shells in this way, but the holes that they leave behind are straight-sided). The hole was made by a combination of acidic chemicals that softened the shell’s calcium carbonate and the teeth or radula of the predator that physically scraped it away. Once the hole was made, the predatory snail could squirt digestive enzymes into the bubble to turn it into a liquid lunch! So, traces like these left on fossils can often tell us a lot about the ecology of the animal, including how it lived and died.

*For more about Katherine Palmer, see Fossil of the Week 2/3/10 – A Rib-less Wentletrap.

**For a definition of paratype specimens, see Fossil of the Week 10/14/09 - Atrypa aperanta Crickmay.





Text by Paula Mikkelsen

Friday, December 3, 2010

This Weekend at the Museum



Looking for something fun to do this weekend? Head out to the Museum of the Earth for Cecil's Dinosaur Holiday Party from 11 a.m. to 3 p.m.

Touch and feel history through hands-on exploration of fossils at the Fossil Lab and Dino Lab Discovery Stations. Take your picture with Cecil, make a fun winter snow globe, and more!

From 11:30 a.m. to 1:30 p.m. watch Amazing Pete create fantastical balloon sculptures and take one home with you!

Included with Museum admission, free for members.

This event made possible with generous support from the Cayuga Medical Center.