Reptiles
In our reptile lecture, we will be talking about the characteristics of reptiles, their scales, development of the snake embryos, and a few of the orders of class reptilia.
Characteristics of Class Reptilia
Pets on webcam during class time is fun.
There are five characteristics that we will talk about for class reptilia. One of the characteristics that we will spend a little time on is the fact that they are covered with tough, dry scales. They breath with lungs. How many chambers do they have in their heart? Why will that type of heart work for a cold-blooded creature? Their eggs are leathery unlike a bird's egg which is brittle due to lime (contains calcium) in their shells. If they have any legs (remember that lizards and turtles are in this category too, not just snakes) they will come as t
Snake Embryology
Briggs' egg incubators
Snake eggs are leathery and have an interesting internal structure in a fertilized egg. The yolk is the embryo's food supply. The allantois (all-en-toe-is) is the sac of blood vessels that allow for respiration and excretion of the embryo. The amnion grows around the developing embryo in which it floats. This structure also is responsible for the immune system of the developing embryo. The shell has to be porous enough to allow gasses to be exchanged and sometimes the shell will become damaged. Pathogens can get past the shell and the amnion will ward of the dangers of infection. The skin-like layer between the shell and the contents of the egg is called the chorion (kor-ee-on).
Snake Venoms
Another interesting topic is snake venom. There are several types. Some are neurotoxins. Coral snakes will give you a good dose of this type of toxin. If you are unfortunate enough to be bitten by one you will find that the toxin will seize up your nerve centers causing paralysis that can stop breathing. There are hemotoxins too. Copperheads give this type of venom. Hemo means blood and this toxin goes after the circulatory system. It will weaken blood vessels until they rupture. The last one we will talk about are cardiotoxins. These deteriorate the muscles of the heart specifically. This toxin is the one that is in cobras.
Class Squamata
Snakes are not the only embers of class reptilia. We will talk about geckos, chameleons, horned toads (not toads at all), and gila monsters.
Order Testudines
Do you know what the difference is between a turtle and a tortoise?
Order Crocodilia
Do you know the difference between an alligator and a crocodile?
Dinosaurs
Reptiles keep growing their whole lives. Could that by why the dinosaurs got so big? Could they have existed when life spans were longer and because they kept growing their long life span gave them great size? Since dinosaurs do not exist anymore other than the tuataras (two-ah-torrah), it is fun to ponder possible explanations.
Reptiles Slideshow
Enjoy the slide show of VHSG students and families that have made reptiles a part of their lives for a module or for a life's work.