Did you ever wish your skin was covered in fingernails, or that you could shoot blood out of your eyes? Have you ever tried to breathe through your skin? This week, we talk about reptiles and amphibians, and have a very special guest: a real, live horned lizard!
THE BASICS:
Amphibians have moist skin that they use to take up water and also oxygen from their environment! They also have what we call a "complex" life cycle, meaning they start as one thing (like a tadpole) and then change into something else (like a frog) over their lifetime. Amphibians have to lay their eggs in water.
There are 3 groups of amphibians: frogs (& toads), salamanders, and caecilians.
Reptiles have skin covered in scales - a protective covering made of the same material as your fingernails or hair, a protein called keratin. They can lay their eggs on land because the eggs are covered in a leathery shell which keeps them from drying out.
There are 5 groups of reptiles: lizards, snakes, turtles, crocodilians, and tuatara.
VOCABULARY
Reptiles and amphibians are alike in that they're both ECTOTHERMIC. This means that their body temperature is controlled by the outside environment (like laying on a rock in the sun to warm up). The opposite of this is ENDOTHERMIC, which is what we are - our bodies do all the work to keep us the right temperature, and we never need to lay in the sun (unless we want to).
This horned lizard helpfully demonstrated a trait called TONIC IMMOBILITY. It's a natural state of paralysis that nobody can really explain, though it might be like playing dead to deter a predator.
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This production is brought to you by the University of Arizona's Community and School Garden Program and Penny the cat (even though she was hiding behind the couch for this one).
Thanks to the Thomas R. Brown Foundation, Cox Communications, and the Roche Foundation for their support.
PS: my t-shirt this week features another awesome lizard, the gila monster! This shirt was designed by a local Tucson artist who could probably use your support about now. It also comes in kid sizes! popcycleshop.c...
22 авг 2024
