The Evolution Of The Four Chamber Heart
I know this isn’t exactly the most beautiful picture so I doubt it will stop many of my fellow tumbl-weeds scrolling down through their dash but I think this is incredible.
We began life with a heart that merely acted as a nutrient pump. An axial tube which pushed blood from one end of the body too the other by peristalsis (if you’re not a med that’s the evolutionary equivalent of pushing toothpaste out of a tube).
As we evolved we had to develop a more organised system so we moved to the fish heart on the top left. Which pumped blood through the gills for O2 and the residual pressure pumped it through the rest of the body.
As our amphibian ancestors developed lungs we had to develop a parallel system with a mixing chamber when we were above water.
As we evolved even more a progression toward the four chambered heart and parallel pumps was favoured by evolution.
N.B. Another beautiful observation is how closely related our embryonic heart tube and fish hearts are. If that’s not support for evolution, I don’t know what is.