The Classification and Taxonomy of Life (+Amphibians & Reptiles)

This is more interesting than it sounds, I swear!

Okay, first for some definitions. Taxonomy is the science of naming organisms based on one set of criteria. Classification is the sorting of a variety of items into manageable groups. And systematics is the arrangement of groups based on status/taxon in this case.

So it’s likely that you’ve memorized the order of the taxons at some point in your life. Here it is again: Kingdom, Phylum, Class, Order, Family, Genus, Species. You also probably know that we use the binomial system (mainly Latin words) universally to prevent miscommunication.

Now, the natural system of classification is based on a number of things:

  • Morphological characteristics (how they look)
  • Behavioral characteristics (how they behave)
  • Biochemical/chromosomal comparisons (DNA) – according to phylogenetic (evolutionary) relationships
  • Homologous characteristics (similarities of origin)
  • Analogous features (similar functions but no common ancestor)

Together, scientists have created (and are still adding onto) an evolutionary tree of life. We can track the evolution of primates through these phylogenetic trees.

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So why do we do this? What is the purpose? What is so valuable about classifying all these species? Well, we can see evolutionary relationships, we can name and identify organisms reliably, and importantly, we can fight against invasive species.


All right, now we’re going to get into the fun stuff, now that I’ve forced you to learn something new, or at the very least, I’ve made you review something you already knew.

Do you know your reptiles and amphibians?

Turtles, crocodiles, caecilians, snakes, salamanders, toads, frogs, lizards, which ones are which?

Well, hopefully you do know. (Turtles, crocodiles, lizards, and snakes are reptiles, and the salamanders, caecilians, frogs, and toads are amphibians.)

So what makes these two groups of animals different, anyhow?

Reptiles have tough, scaly skin to prevent water loss. Their hearts are divided into more chambers for a more efficient, sustained muscular activity. They are oviparous (egg-laying) creatures. Some are oviparous – their eggs are hatched outside the womb. Some are viviparous – they give birth to live young.

Amphibians are an abundant group. They are sometimes foragers, or they sit and wait for their food. They have wet, thin skin, and except for Caecilians, have developed legs. Some of them have webbed feet, and adults are carnivorous.

  • Snakes rely less on their sight and more on sensing smell and vibration. They capture their prey either by constriction or by injecting them with venom from their salivary glands. There are four groups of snakes, based on their teeth and their venoms.
  1. Aglyphous – the constrictors, have no venom
  2. Opisthoglyphous – weak venom, their rear teeth are haemotoxic, and have rear ward grooves
  3. Proteroglyphous – venoms are neurotoxins, have short front fangs, have forward grooves, and the juveniles are particularly more dangerous because they have less control over their venom
  4. Solenoglyphous – cytotoxic venom (breaks down cellular tissue), they open their mouths 180 degrees, fangs are folded back into the roof, and have pipe grooves
  • Often, amphibians such as salamanders and frogs can be used as habitat indicator species. They can be sensitive to environmental changes and their population can indicate the health of the forest. This also means that they are really sensitive to global warming and all the terrible things that we are doing to our planet, and may be the first to go.

Thanks for reading! Hope you learned something new. ~Gloria

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