An introduction to PhyloTree, a browser for the Tree of Life (or at least a very rough approximation of the Tree of Life) available at dunnlab.org/phylotree .
This video demonstrates some of the features of PhyloTree. It then shows the early explosive discovery of mammal species (most major mammal groups were discovered early on), and then shows the slow and steady discovery of cnidarians (many cnidarians remain to be described). The tool can also be used to quickly find the first species that was described in a group. The first siphonophore to be described, for example, was Physalia physalis (the Portuguese man o’ war).
Léon-Eugène Méhédin was a photo-journalist in the mid 1800s. After documenting the Crimean War, the Italian Campaign of Napoleon III, and taking pictures in Egypt and Nubia for a photographic encyclopedia, he traveled to Mexico with the French Expeditionary Forces. There he claims to have discovered the ruins of Xochicalco. He took papier machê molds and many photographs, all of which were reported to have been too artistic to be of any scientific value, and have never been seen since. Upon their return from Mexico, the French Expeditionary Forces brought 34 funny mexican salamander-like animals back to give to the Natural History Museum of Paris.
These animals, called axolotls, were first seen as a scientific oddity; they spend their whole lives looking like the larval state of a salamander, but they become sexually mature and can reproduce without metamorphosing into the adult form. In 1863, Méhédin gave 6 of these animals (and then one more, a few years later) to a local biologist named August Duméril, who started breeding them and enthusiastically sharing thousands of them with his colleagues all over Europe.
Since then axolotls have become one of developmental biology‘s model organisms, mostly because they are easy to raise, their embryos are large and transparent, and axolotls can regenerate their limbs and heart. In that same time, the original populations of wild axolotls, which live solely in the lakes in and near Mexico City, have dwindled to the point of near-extinction. The vast majority of axolotls alive today are being bred in developmental biology labs across the globe. Most individuals can be traced back to two of those 7 axolotls from Méhédin in the 1860s.