London Natural History Museum: Marine Reptiles of the Dinosaur Age

Wednesday, December 15, 2010
By Student Group

The 9th grade biology students recently traveled to London for a week-long field trip to many historical sites.  The students spent three hours exploring the Natural History Museum.  The following is the seventh in a series of posts written by the students to discuss what they learned.


by Deirdre, Gurk, and Josh B

This past month our school took a trip to London to see a various amount of historic places. One day we went to the Natural History Museum where we looked into the Darwin Centre with the entire grade then split off into groups to visit separate exhibits. At the Darwin Centre our group particularly enjoyed an exhibit where scientists discussed how to make specimens ready for examination. We learned that while preparing insects, the scientist will first pin a needle into the side of the insect after being watered down and place it on a white board. Smaller pins are then placed to secure the insect’s smaller limbs. Before the insects are examined closely, they are left for a week while they dry. To make plant presses, there is an entirely different process. The scientist first takes the plant and lays it on acid free paper (to reduce deterioration). They will then take glue and apply it to the underside of the plant and lay it down again on the paper gently. Wax paper is laid on top before the paper is put into a press for 10 to 15 minutes. Plant presses are constructed with a wooden frame, with cardboard ventilators, made so that air can pass through the press. To tighten a press the scientist will use straps with buckles. To prepare slides to put under a microscope you need to take apart whatever you are studying (animal or plant) so that only the part you are interested is placed on the slide. Then place water on top of the animal or plant part, cover it with glass, and then put the slide into an oven for a week to dry off.

In the Fossil Marine exhibit there were many fossils of extinct animals. Most of these fossils were found by one person, Mary Anning. She was otherwise known as the “Fossil Woman”. She was born in 1795 and died in 1855 of cancer. She got her fossil hunting knack from her father Richard.  But, her mother, also named Mary, hunted and sold fossils to keep the family afloat. Mary Anning married Gideon Mantell, a British fossil collector, and he donated all of their collections to the British Museum. She lived in Lyme Regis which was a good fossil hunting spot; because 200 million years ago it stood in an area near the equator. This was a tropical spot where marine fossils were rich in the seabed.

All of the fossils we saw in the exhibit were types of ichthyosaurs and plesiosaurs. After some additional research we found out that ichthyosaurs were reptiles of the dinosaur age that were strongly adapted to life in the waters. Ichthyosaurs dwelled in dark places of the water and gave birth to live animals, making them mammals. Ichthyosaurs dived so deep that scientists believe that these animals had to have been nocturnal to see at these amazing depths. Ichthyosaur eyes have been shown to be similair to cat eyes, showing their adjustments to dark areas. We learned that plesiosaurs are less fish-like than icthyosuars and had long necks with very short tails. The name plesiosaur actually means “near reptile” or “almost lizard.” A difference from ichthyosaurs is that plesiousaurs are believed to have layed eggs in the sand, similar to the method used by modern-day sea turtles. Another interesting fact we discovered is that these pleasiosuars are actually the animals that some people believe to be the Loch Ness Monster.

After looking into the evolution of icthyosuars, our group was surprised to see that these animals of the dinosuar age were actually closely related to some animals we know of today. Ichthyosaurs were lizard-shaped and the way they moved about the water changed the body shape of swimmers in evolution. Ichthyosaurs share some characteristics of living catsharks. They both have a slender trunk, skinny backbone, and high number of vertebrae (alowing them to swim in squiggly shapes). When researching the evolution of plesiosuars, we couldn’t find many leads on what animals have become like these sea serpants, but we did discover what the animal had evolved from. This animal was originally called a Thalassoidracon, an animal that averaged at only 6-feet. The plesiosuar was an animal that was discovered at 55 feet long. Over the time from the late Jurassic period to the Cretaceous period, these animals grew greatly in size. Fossils of these incredible animals are fairly rare and the Natural History Museum is lucky to have acquired them.

In conclusion, we have learned a lot on our trip to London. It was a great experience going to the Natural HIstory Museum. We expected to learn new things about the fossils we saw and it was cool to see into the life of a scientist at the Darwin Centre.

What other museums hold fossils of ichthyosaurs and plesiousuars?  How are fossils such as these prepared for examination and display?

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  • Leyla

    Fantastic post, Deirdre, Gurk, and Josh! In response to your question “What other museums hold fossils of ichthtosaurs and plesiousaurs?” I found that there is a 240 million year old ichthosaur fossil at a museum in Norway called Tromsø University Museum. It was discovered between 2006-’07 and went up on display in 2008. The fossil was found in a deposit of sandstone and is a particularly large specimen of it’s species, having been approximately 10-12 metres long in life. About half of it–six metres–was actually discovered. Though I could not find many details, I also discovered that many scientists prepare the fossils for display using methods like acid baths and vacuum impregnation.
    http://www.science20.com/news_releases/unique_240_million_year_old_ichthyosaur_fossil_goes_on_display
    http://www.ucmp.berkeley.edu/faq.php

  • Anonymous

    Great post guys! After reading your question ” How are fossils such as these prepared for examination and display? ” i was really curious to see how fossils are prepared, knowing from prior knowledge that they are brittle objects, that require very special care. First they have to remove the matrix which is also known as the sedimentary rock that surrounds the fossil but they must do this cautiously to make sure that the fossil is not damaged, because they could lose important information about our past. After this they can carefully observe and take note of the fossil.

  • Anonymous

    Hi guys, fascinating post! Congratulations on all the information you were able to get out of your time at the exhibit! I did a little more research on how fossils are prepared for examination and display. The first step is documenting and actually discovering the fossil. There is a greast story that is told by every fossil and so every detail is written down. The next step is collecting the fossil. A fossil can be very fragile because of how old it is so they use a process called feild jacketing. Feild jacketing is when the area around the fossil is extracted to determine the extent of the fossil. Then the fossil is “covered in a plaster and burlap cast. This cast supports the fossil and protects it while it is cut out of the surrounding rock and transported to the laboratory where more delicate cleaning of the fossil can take place.” If a fossil is extremely fragile, the preparer may coat it with consolideants (resins that strengthen the fossil). The next step is preparing the fossil. When a fossil is collected it is usally cleaned up to to remove and dirt and sediments present on the fossil. To do this, many tools are used such as brushes and mini air hammers. If a fossil is unstable and may not withstand this type of cleaning, adhesives are applied to it in moderation to prevent it from degrading. The prefered content to clean the fossil soaks into the fossil to give it support from the inside out.

    http://animals.about.com/od/evolutio1/qt/fossil-preparation.htm

  • http://extremebiology.net/blog Ms Baker

    Source? Be more specific. How do they remove the matrix?

  • Anonymous

    Great post, guys! Unfortunately I was not able to see this exhibit, but our exhibit was dinosaurs so I feel like I can relate a bit! I decided to do research on your question of where you can find a fossil from the Plesiosaur and there is one in the Natural History Museum of Olten. It’s 15 in long, has the head and snout, containing 200 teeth. It contains a few neck vertebrae and a small part of its rib cage.

    Source:
    http://www.plesiosaur.com/creationism/swissichthyosaur/index.php

  • http://extremebiology.net/blog Ms Baker

    Sources? Maybe to add something new, where did the following phrase come from? Ever heard of it?

    “She sells seashells by the seashore”

  • http://extremebiology.net/blog Ms Baker

    Cool! Where is your source of this information?

  • Anonymous
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