Images from Fieldtrip to KU Natural History Museum, July 2013. We are examining the fossil of the Mosasaur that is the “mascot” of the Museum. This specimen was found in Western Kansas, which used to be part of the Inland Sea during the Cretaceous Period, about 80 million years ago.
In these images Dr. Pierotti is explaining the evolutionary concept of Homology, which reveals evolutionary relationships between animals that look very different. The students are learning about how the bones in the Mosasaur’s foreflipper are basically the same bones that humans have in their arms and hands.
Dr. Pierotti is holding his hand next to the flipper for comparison.
In this image Dr. Pierotti is showing the students that the bones in the human arm: Humerus, Radius and Ulna, can also be seen in the flipper in the classic vertebrate pattern of one bone (Humerus) connected to shoulder or pelvis, two bones (radius and ulna) below the Humerus, and then multiple bones forming the wrist, palm, and digits. This pattern is the same even if the bones may look different because of adaptations to different environmental conditions by different species. In this case the Mosasaur uses its forelimb as a flipper for swimming, whereas humans use their arms for a wide range of functions.
Dr. Pierotti and students are discussing the similarities and differences between fossil whales from the Eocene Period and Contemporary Dolphins. This exhibit in KU's Natural History Museum shows an evolutionary series of whales from four-legged dog-sized ancestors, through crocodile like whales to modern whales. The skulls on display show how the front of whale skulls became longer over time by extending the bones at the front of the jaw creating a snout.
Dr. Pierotti is showing the students a model of the structure of the DNA molecule. This molecule is the basis of all life and its ability to reproduce itself so that all members of the same species look basically the same in overall appearance. The students had previously studied DNA in their classroom exercises and all of them recognized the model when they saw it so we were able to discuss hydrogen bonds and how they work in DNA.
Teacher Tammy Jones and a Summer Academy student examine a model of the HIV Virus that causes AIDS. This model led to a discussion of whether or not viruses are actually living organisms. Some students felt that because they contain DNA or RNA that they are alive. Other students argued that because they cannot reproduce on their own and depend completely on other life forms for energy and the ability to replicate their DNA means that although they resemble life, and have some features of life, they are not truly alive.
Dr. Pierotti and students examine an exhibit that shows how Leaf-cutter Ants in the Tropics have "domesticated" species of fungus that provide their main source of food. The ants actively take care of these fungi, protecting them from bacterial infection. Many different species of ant do this and each has its own species of fungus that it has domesticated and cares for as a food source.