“Ontogeny recapitulates phylogeny” is a phrase that many of us learned in our biology classes. It describes the theory that an organism’s development (ontogeny) reflects its evolutionary history (phylogeny). The theory was popularized by Ernst Haeckel in the 1800s, and is also known as the biogenetic law or embryological parallelism.
However, the theory has been criticized since embryos don’t always develop in the strict progression that Haeckel claimed. For example, echidnas develop their limbs later than most other mammals, and human embryos have gill slits and a tail that are later resorbed. Even when the theory was introduced, many scientists recognized that it wasn’t true and by the mid-20th century, it was considered “biological mythology”.
The theory is too orderly and clean, and biology is messy.
However, biology does seem to conserve useful structure development and implement different uses for these in different phylogenetic branches.
Examples that come to mind are the gill lamellae of fish and the fine structure of a bird’s feather. I never noticed this one until I once took a macro photo of one of Gizmo’s feathers and under that level of magnification the resemblance was remarkable.
Walking home today another one was soobviaous on the surface of the trail. Weather and footsteps have worn the loose soil and sand away, exposing the root structure of an old tree. The branching structure is so reminiscent of a vertebrate nervous system, or even the circulatory system.
Today was a challenging day for me, I’ve been struggling with some things for a few weeks and I am trying to find my way through to the other side. But these paths do give me a little bit of sanctuary at both ends of the work day. They give me time to think, they give me time to redirect my mind if I allow it.
On some level it heightens a bit of my sense of loneliness.
On another it gives me a bit of peace.
Are those so different?
I think, experience, and/or learn new things every time I walk the trails.
A tree and a human, we are more alike than we usually consider, and spending a bit of time together does seem to lower the blood pressure and, sometimes, give a little bit of a reset.
