52 - Salamanders (w/ Mike Itgen!)
52. Salamanders
Some of my earliest memories of science were simply hunting for the elusive Pacific giant salamander in the coastal northwest. Today, we’ll talk about these slimy amphibians and how they contribute to scientific research. Let’s learn to be scientifically conversational.
General Learning Concepts
1) What is a Salamander?
a. What is a lizard? Lizards are part of a group of animals known as reptiles. Many lizards today resemble the ancient reptiles of the dinosaur era. Their ancestors appeared on Earth over 200 million years ago. In general, lizards have a small head, short neck, and long body and tail. Unlike snakes, most lizards have moveable eyelids.
b. What is an amphibian? First evolved around 350 million years ago. Vertebrate, cold-blooded animals that reproduce in water (or a moist environment). Scaleless. Include frogs, toads, salamanders, and newts. Earliest tetrapod to evolve. [2]
i. Caecilians (pronounced “see-seal-ee-un”) are long, slender, legless amphibians superficially resembling earthworms or snakes
c. What is a salamander? Looks like a lizard, but not the same thing! Salamanders are moist, lacking scales and claws, and many use their wet skin in order to breathe. In most species, the male places sperm packets into a pool of water which is later inserted into the female cloaca. Salamanders tend to eat small animals like insects or worms.
2) What are some distinctive characteristics of salamanders?
a. How are salamanders breathing through their skin? Research shows that within the dusky salamander, lungs start to form but never fully develop. Studying the gene activity within the extra blood vessels in the skin identified a gene that encodes for a protein to help membranes increase their ability to do gas exchange.
b. Parenting: Ambystoma, a six-million-year-old salamander lineage that produces only female offspring, is capable of balancing gene expression from contributions of three separate salamander species’ males. When the female mates, she undergoes kleptogenesis (taking genetic material from the male donor for eventual downstream reproduction).
c. Venomous salamander: When toxins are ejected from an organism into another, that organism is venomous. If the organism is eaten, or its secretions are eaten, poisonous animals are toxic. Some salamanders are venomous and can push their ribs through pores that run down their bodies and begin secreting toxins from internal glands.
3) Why are salamanders relevant in research today?
4) Fun Tidbits
a. What is a group of salamanders called? A herd or congress.
b. What is the largest salamander? Chinese giant salamander (Andrias davidianus). It can be up to 6 feet long!
5) Solicited Questions
a. Is a salamander a lizard?
b. Why do we need to prevent salamander extinction?