Our Planet: Why the Earth is one living creature
We generally think of living things as “particular” organisms – a tree, a mouse a bird. However, it doesn’t always make sense to think of creatures as individual living things. All life on Earth is fundamentally linked, all part of the same big system. All creatures rely on other creatures, either to eat them, live inside them, or live alongside them. Through the ecosystem, from plants to herbivores, to predators to fungi, all is connected. All life on Earth is linked in terms of evolutionary history, with every single creature sharing the same type of underlying genetic code and evolving from a single ancestor. Really, at the end of the day, there is just life. All of it special and all of it sacred. Let’s dive in.
The Connection of Life
All life on the planet is connected. And it is connected in many ways.
The most obvious way is with food chains. Almost every creature relies on other creatures to eat. As a general rule, plants and algae take energy from the sun. Herbivores eat these algae and plants and carnivores eat these herbivores. Eventually, even the things that don’t get eaten by other animals die and microbes and fungi eat their bodies as they decompose, turning back into nutrients that the plants and algae use, forming new living things. In this manner, plants and algae play a crucial role in holding up all the other living things, the start of every food chain. They are the foundation on which all other life is built.
These food chains are delicate things and can topple under pressure. When conditions aren’t right for plants or algae and they don’t grow, herbivores starve, and carnivores go hungry. If plants and algae disappeared from the planet today, life on Earth would almost completely collapse. Very quickly, almost all animals would starve. However, this is true on an ecosystem level as well – a few plants dying out in an area can have a massive effect on all the surrounding animals and plants.
However, it’s not just plants that are important to ecosystems – animals play their role as well. If something were to reduce the carnivores of a system, the herbivores become more abundant, eat all the plants and then they starve. A particularly spectacular example of this is the removal and subsequent reintroduction of wolves from Yellowstone National Park, see how wolves shaped a river. Basically, when the wolves were removed, the deer populations in the Park flourished and this resulted in the young sapling trees being eaten, affecting the growth of forests. This had a flow on effect to hundreds of different species which relied on the woods – birds, beavers, otters, coyotes and other different plants and animals. When the wolves were re-introduced, the deer populations shrank and many of these animals started to return. It wasn’t just that one species was taken away, a part of the entire ecosystem was removed.
All things are also connected through the shared history of life on Earth. Every living creature has DNA and shares a common ancestor. This is something that most people understand, but we don’t think most people have really absorbed it. Everything single living thing is in some way related to you. It is so easy to imagine, a different world where we had a few different types of creatures – maybe some carbon-based creatures that were all related, some silicon-based creatures, some metal ones, each type unable to interbreed, each having different chemistry. But we don’t live in this world. Instead, every single organism, from the smallest mushroom to the largest whale has come from the same source over billions of years of evolution.
The idea of a single organism is kinda dodgy. Every complex creature generally has thousands of other organisms living on it, or inside it, helping it survive. The human body has more bacteria cells in its gut than actual human cells. The bacteria help humans digest food, breaking it down into chemical compounds and even fight off other types of bacteria that are harmful to our health. Different humans have different profiles of these bacteria and when they get sick or ill the profiles change. This even occurs with single-celled organisms – almost all protists swallow smaller organisms to help them digest certain foods. The trees in forests all link their roots together and share resources like water and nutrients as one large organism via fungal networks. Even some species we think of as a single species are actually several living together – lichens are a fungi combined with a cyanobacteria, almost all trees have a large number of fungi living on them, performing various functions to help the tree out, a lot of jellyfish are actually just colonies of smaller single-celled animals.
And it even goes deeper than this. The earth itself is part of this system. All the oxygen in the Earth’s atmosphere was created and is replenished by plants and other photosynthesizing creatures, who take out the carbon dioxide in the atmosphere created by animals breathing and things decomposing. When these photosynthetic organisms initially evolved, they became so successful that they fundamentally changed the Earth’s atmosphere (see our post). This new atmosphere changed the earth by allowing new life to form and created a deep red band of iron rust, from rusting a large amount of exposed iron for the first time. Many of the rocks of the Earth itself are made from long-dead creatures – coal is made of decomposed Jurassic and Triassic ferns, and all limestone is made from the fossilized shells of algae. There has been life on Earth for so long that every atom has been in many things – some alive, others not – entering in and out of these cycles in one closed dynamic system, the Earth.
So life is connected – why should we care?
One of the worst things about the Western-educated way of thinking is a tendency to dissect as opposed to connect. To understand life on Earth, we have divided it down into species, then into organisms, then into particular body parts and tissues and cells. We want to understand incredibly complex systems, and so we break them down into ever smaller and smaller compartments: isolating, disentangling, dissecting. This all makes sense and is very useful to understand and treat ailments of an individual organism like doctors do. It also is useful to engineer better organisms, like agricultural scientists do, to try and grow more food. It is a really good way of understanding the world and it has taught us a lot.
However, the problems of the 21st century are about connection. The health problems our species suffers from now, like obesity, heart disease and global pandemics tend to come from the interconnectedness of society, as much as they do the biology of an individual organism. The environmental problems we face, like pollution and climate change, are at a much larger and more systemic scale. As much as we try to think about ecosystems and assess things at a higher level, we always tend to think in an isolated way, focussing on the actions of particular individuals, companies or countries. Our legal, cultural and political systems are designed to protect individual animals, individual species, and individual places – not the Earth itself. At the end of the day, we still drive our cars, buy things in plastic, all under the justification of, “Well I’m not doing that much damage”.
A lot of scientific research focuses on individual species. For example over the past few decades, the insect population of the Earth has been decimated – falling by up to 60%. People even have anecdotal experience of this. Think back to when you were a child and going for a drive through the country. Think about how many insects used to get splattered on the windscreen? When you ran through a field, how many bugs used to suddenly fly up out of the grass to avoid you? Now think about the last time you did either of those things. Was it different?
People don’t care about a lot of animals – certainly not insects. They aren’t cute. So falling insect populations don’t trigger much of an emotional response. We see it as a change affecting one group of animals – a group we don’t care about that much. But insects do so much, as part of the Earth’s ecosystems. Some species of plants are entirely dependent on being pollinated by exactly one species of wasp – so if that species of insect dies, then that plant dies. In order for most fruits to grow or crops to seed, they need to be pollinated by one of a few species of insect, so if those insects start to decline, it suddenly becomes much harder to grow crops. Roughly $600 billion dollars worth of annual labor is created by these pollinating insects every year. In areas where insects are already dying out, we are starting to need to pay people to hand pollinate plants – and it’s hard, it takes thousands of hours of work to pollenate a field of crops. We take it for granted that when we bury dead things they decompose, and we don’t stop to think that something does that – insects. Insects are actually great, some are bright rainbow-colored and can punch through glass walls, but even if you don’t think that the role they play in life on Earth is absolutely essential.
Now combine this effect from falling insect populations with the other effects of human pollution. Half of all amphibians are endangered with 2.5% having gone extinct within the last decade. We have lost half the coral on the planet since 1950 and at current rates, reefs will not exist in thirty years. A third of all marine mammals are threatened. All of these things are combining together to affect the Earth’s biological systems. In fact, most biologists now agree that the world has entered its sixth mass extinction event, which is starting to look comparable to the meteor that hit the Earth 50 million years ago and wiped out the dinosaurs and 80% of life on Earth. But aside from a few researchers screaming into the void, most people really struggle to see that. They only see countries and borders and individual species and animals. They don’t see the Earth itself.
We don’t have to think in this isolated way. A lot of other cultures don’t – particularly Indigenous cultures. Many native people had a much better intuition about ecosystems and the connectedness of life. For example, Indigenous Australian tribes were often separated into different groups and each group was assigned to a particular animal or plant – a magpie, a kangaroo a wattle shrub. People in these groups would then learn about the animal and its relationship to other animals in the country, how and where it lived, with knowledge passed down from the elders. They would be responsible for managing the population of this animal throughout their lives and ensuring it was in its proper place. These animal totems played and continue to play a central role in a lot of Indigenous societies, with families and ceremonies all structured around them – they thought of it as a central part of being a person.
There are such limitations in the way we see the world. And they are having devastating consequences. To solve the problems of the 21st century, we need to start seeing things differently. To see the Earth as it actually is, one living thing.
