If you study evolution and palaeontology, whether it is diplodocus or drosophila, hadrosaurs or hominids, at some point you are likely to make use of, or even make your own, phylogenetic tree. These trees are really the holy grail of evolution studies, showing the relationships between species, what evolved from what and, in some cases, how long ago their common ancestor lived. They can be built by comparing similar characters in a creature’s appearance, like number of legs, or how they reproduce. Alternatively, modern evolutionary biologists use the information-rich genetic code in living organisms to make and compare many trees, ultimately resulting in one that most accurately represents the true course of evolution.
Making a tree inevitably involves a lot of number crunching, but the resulting diagram is elegant and informative. Try this general one of eukaryotic life
Phylogenetic Tree of Eukaryotes
Here, Bacteria have been used as an ‘outlier’ to compare all the other members of the Eukaryotes. Each branch marks an evolutionary ‘divergence’ – a novel change that created that group of organisms. For instance, the invention of chloroplasts led to the all the members of the plant kingdom, just as the invention of feathers led uniquely to birds. The fewer the number of branches between two creatures, the more closely related they are. For instance, we are more closely related to cows and whales, than we are to marsupials.
So to a graphically minded palaeontologist, a phylogenetic tree is quite a thing to behold, but there is a way of making them even better. For many, more detailed trees, you may be dealing with specific species, and lots of them. Take this now-famous ‘megatree’ of all the dinosaurs:
Dinosaur Phylogenetic Tree. Lloyd et al Royal Society
While it is undoubtedly a breathtaking piece of work, with a striking design, its usefulness is questionable to all but the most dedicated head-tilting members of the vertebrate palaeontological community. More and more trees are appearing with more and more information crammed into them, and they are no longer the elegantly informative diagrams they once were.
But there is a growing trend to making phylogenetic trees beautiful and readable again, using silhouettes of the creatures being compared, rather than, or in addition to, their names. And hopefully this graphically gorgeous trend will continue with the launch of PhyloPic a new open database of life form silhouettes for use in phylogenetic and other applications. Here’s an example:
Rangifer tarandus (reindeer) from PhyloPic
The open source database is encouraging submissions from registered users (registration is as easy as pie) of silhouettes of any creature, in solid black, to be used under a creative commons license. Users can search the database for the latin or the common name, and download the image in a variety of sizes and manipulable formats.
At the moment, the search and browse facilities are still a little clunky, and the database is rather sparsely populated with some odd looking silhouetted. What on earth are these?
Mystery silhouettes from PhyloPic
They are, in actual fact (from left to right): a single-celled symbiotic euakryote, a placozoan, a human baby, a choanoflagellate, and a pterosaur. Perhaps a little more contecxt will make these silhouettes a little less mysterious.
Needless to day, as an artist and a palaeontologist, I heartily approve of this new resource and I know I’m not alone – the young palaeo-community has got silhouetted ants in their pants with excitement over it. I will certainly be contributing some images over the coming weeks, and I encourage any other artistically minded palaeontologist, zoologist or miscellaneous scientist to help to build this wonderful database.
Browse or contribute to PhyloPic here: http://phylopic.org