Image Credit: mstk east, CC BY 2.0, Image Cropped
Thanks to DNA sequencing, there is no escape from the reality that every organism is an ecosystem. I like to think of myself as an individual human organism but actually, I am a holobiont, playing host to thousands of other species. Back in college, my body was an ecosystem in distress. A diet of coffee, beer, and bagels coupled with a steady dip of stress led to a series of health issues and an eventual diagnosis of ‘dysbiosis’. Dysbiosis is a term that describes a loss of microbial biodiversity or departure from a balanced ecology.
Image Credit: ForestWander.com CC BY-SA 3.0 US, Image Cropped
Somewhere in my education, I distinctly remember a video that explained ecosystem succession moving towards a climax condition. The film depicted the gradual filling of a lake and subsequent encroachment of saplings as the system aged towards its inevitable end as a hardwood forest in the eastern United States. I remember thinking even then, “but where do lakes come from?” I couldn’t work out how there could be a mosaic of habitats if there was a steady progression towards a single endpoint.
Using eDNA, we can figure out where shy animals like this platypus live without disturbing them (Image credit: Amber Noseda, Great Ocean Photography, CC BY 2.0)
As an undergraduate student, more than twenty years ago, discussions of species often referenced ‘lumpers’ and ‘splitters’. Some biologists were more likely to ‘lump’ all variation within a single species while others attributed variation to distinct subspecies, and ‘split’ organisms as such. Back then, we talked about biomes such as forests and grasslands but the term ‘microbiome’ barely existed. Now, even the concept of an organism is questioned as some scientists argue that the individual cannot be separated from the microbiome it hosts. Thanks to advances in molecular biology, every organism is now an ecosystem.