Get ready to have your mind blown as we explore the fascinating question: How much of our bodies is truly 'us'? Prepare to question everything you thought you knew about humanity and identity!
In the late 17th century, an amateur scientist named Antonie van Leeuwenhoek made a groundbreaking discovery. Through his homemade microscope, he observed tiny, living creatures in plaque samples from his teeth and those of others. These 'animalcules,' as he called them, were none other than bacteria! Van Leeuwenhoek's curiosity led him to collect samples from various sources, revealing a hidden world of microscopic life.
But here's where it gets controversial... How much of our bodies are actually human cells?
Fast forward to the 20th century, and scientist Thomas Luckey estimated the ratio of bacterial to human cells in the colon to be 10:1. This ratio was widely accepted until a team of researchers revisited the topic in 2016. Their findings? A more conservative estimate of 1.3:1, indicating that, on average, we are slightly outnumbered by microbial cells.
So, are these microbes just hitchhikers, or are they an integral part of us?
Associate Professor Andrea Stringer suggests that, functionally speaking, they are indeed part of us. Microbes play a crucial role in training our immune system, digesting complex carbohydrates, and synthesizing essential vitamins. Without them, our bodies and minds would suffer greatly.
But what about our genetic code? Most people attribute the discovery of DNA to Francis Crick and James Watson, but the story goes back much further. In 1869, Swiss biochemist Friedrich Miescher discovered a molecule he named 'nucleic,' which we now know as DNA. Miescher was the first to isolate this substance and suggest its role in heredity.
And here's the part most people miss... We share a significant portion of our DNA with other species! Around 98-99% of our DNA is shared with other primates, and 80-90% with most mammals. We even share DNA with plants and yeast!
But what truly sets us apart? Is it our physical matter, the atoms that make up our bodies?
Professor Karen Livesey, a theoretical physicist, explains that our bodies are mostly 'empty space.' Atoms contain a tiny nucleus filled with protons and neutrons, with the rest being mostly empty. However, the behavior of electrons adds a layer of complexity. Electrons' locations are uncertain due to quantum mechanics, so the 'empty space' in atoms can also be seen as a 'cloud' of potential electron positions.
So, when we touch solid objects, we're not just colliding surfaces. The electrostatic force repels the electron clouds of different atoms, preventing them from coming into direct contact.
But what truly defines us as human beings?
As Karen puts it, 'What makes us 'us' is very complicated.' Our individual differences arise from our unique DNA instructions, but consciousness remains a mysterious, elusive concept. Consciousness arises from the complex electrical transmissions between neuron cells in the brain, but we still have much to learn about this essence of 'us.'
This exploration of the human body and its complexities raises many thought-provoking questions. What do you think defines a human being? Is it our genes, our environment, or something else entirely? Share your thoughts in the comments and let's spark a discussion!
