Today’s Wonder of the Day was inspired by Eliza from Melbourne. Eliza Wonders, “Is planet earth living or nonliving?” Thanks for WONDERing with us, Eliza!
Do you like to learn about the solar system and the other planets that revolve around the Sun? If you've spent much time reading about Mercury, Mars, Saturn, Jupiter, or even former-planet Pluto, there's one conclusion you've probably come to: Earth is the place to be!
The conditions on other planets are often too hot, too cold, or simply too brutal to sustain life of any kind. Earth, on the other hand, boasts the perfect conditions for an astounding variety of life forms.
There are billions of human beings, countless fish in the sea, and an amazing number of animal species. If you add in the insects, bacteria, fungi, and overwhelming number of different types of plants, it's clear that Earth is full of abundant life.
In one sense, it's an easy question to dismiss. No, planet Earth is not a living entity like a human being, a badger, a mosquito, or even a tomato plant. That fact, however, hasn't stopped people from treating Earth like a living creature throughout time.
For example, Native Americans and other native peoples around the globe have long held the belief that Earth is alive. Even the ancient Greeks had a goddess of the Earth that they called Gaia (pronounced "Guy-uh").
The ancient Greek goddess Gaia also lends her name to a hypothesis developed in the 1970s by British chemist James Lovelock and American biologist Lynn Margulis. The Gaia hypothesis, as it's known, is a bit of a misnomer, though.
It's not really a scientific hypothesis that can be tested through experimentation. Instead, the Gaia hypothesis is more like a viewpoint, a perspective, or a way of looking at the world. According to Margulis and Lovelock, Earth, rather than acting like an inanimate, non-living object, instead behaves like a living system.
For example, Lovelock and Margulis noted that Earth appears to display a form of self-regulation, otherwise known as homeostasis. Life-sustaining attributes, such as temperature, atmospheric oxygen content, and ocean salinity, have all been maintained with remarkably little variability.
Furthermore, all of those attributes depend in many ways on living things to sustain them. While the Gaia hypothesis didn't attract much support early on, many scientists in recent years have started to look at complex systems on Earth in a new light thanks to the ideas of Lovelock and Margulis.
In essence, many scientists are now beginning to believe that Earth itself and life on Earth have evolved together over time in such a way that each has affected the other every step of the way. Rather than life on Earth simply reacting to the environment, life on Earth also affects and changes the environment around it.
Viewed in this way, Earth can be seen as a huge, complex system in which the environment and living things interact constantly to form a self-regulating whole. While still not a living organism like a plant, animal, or human being, Earth can nonetheless be seen as a living system that behaves in significant ways like a living organism.