Relationships

Allow me take you on a trip into taxonomy. I have spent a lot of time in the last years studying plant taxonomy so that when I come across an unusual plant in the forest I first start by trying to determine its Family status, and then from there to genus and then species. Some plant families are big and some small. In my state of Massachusetts, the daisy and aster family Asteraceae has 120 genera and hundreds of species. The primrose family Primulaceae on the other hand has but three genera with just four species spread amongst them. 

Now let’s switch to families of mammals. The taxonomic system is the same. A very large family – equivalent to the Asteraceae – would be the Muridae (rodents) with 150 genera worldwide containing 710 species of mice and rats and squirrels etc. A more selective family would be ours – the Hominidae or Great Apes – containing just four genera. Three of these genera – gorillas, orangutans and chimpanzees – have two species each. Then there is the genus Homo and our own species of Homo sapiens. Up until as recent as 40,000 years ago we were not alone, sharing space in Europe with Homo neanderthalensis with whom we did a bit of interbreeding, and possibly a third species in Asia with again some possible interbreeding –Homo denisova. Species of the same genus can sometimes interbreed, but amongst species of different genera interbreeding is extremely rare and mostly impossible.  

Nevertheless, as one goes back in time, not only do those three genera of Primulaceae merge into a common ancestor, but just the same with the genera of the family Hominidae. An significant merger in that journey back in time for us occurs about 5 million years ago when our genus Homo – or actually its direct forerunner – merges with the chimpanzee genus Pan. We’re all familiar now with the letters DNA representing our genetic material. The amount of difference or similarity in one’s DNA is a direct measurement of how long we’ve been apart from these cousins. So my DNA is 99.88% the same as a Neanderthal, and 98.5% the same as a chimp. But then it’s about 70% similar to those rodents, and 30% with those daisies and primulas. So as I walk through the woods, when I see a squirrel or pass by a large handsome oak tree, they are for me my cousins; and I find that thrilling. I hope you might too.