The first land animals appeared on Earth about 350 million years ago but the runway for creatures of our kind to take off was bumpy. Long before that, the first plants had used the Sun’s energy to colonise land but there was nowhere for their waste to go. This upset Earth’s chemistry, causing climate change and contributed to the loss of three-quarters of animal species. At the time, wildlife was living almost exclusively in the ocean. History tells us that upsetting the balance of ocean life has been the trigger for our planet’s worst extinction events. How do animals make our planet liveable? Animal life, like ours, converts dangerous plant energy into a place we can find food.
Energy capture
Everything runs on energy from the Sun and plants are the foundation. ‘Plants’ include the trees, grass and flowers we are familiar with. They also include single-celled algae that live in freshwater and oceans. Seaweed is a type of colonial algae. There are also blue-green algae, which are similar to bacteria.
Plants capture the Sun’s energy and with water & CO2, trap it inside sugars in a process called photosynthesisMeaning how plants extract energy by absorbing water and using radiation from the Sun to combine it with carbon dioxide to create sugars. More. This allows them to create an excess of greenery, comprising billions of tonnes of new material each day. There is more than enough energy in the Sun and elements in the ground for plants to thrive alone. But by doing so, they generate their own waste (energy) and as they die, or shed greenery, it piles up.
The physical impacts of rain, wind and ocean currents redistributes this waste in the landscape according to its topography. Valleys fill with it. This is why we have fertile river floodplains. The fossil fuel we burn today is plant waste that gathered in between mountains 300 million years ago. Left unchecked, this waste will eventually flow into the ocean and end up on the seabed.
This is the way Earth provides a container for life but that isn’t the way we can exist.
The domain of plants
Plants are powerful, abundant and great at distributing energy but it’s not in a form that’s much use to big-bodied animals like us. Plants, bacteria and fungi make up almost 90% of the weight of all lifeforms. It’s often argued that they are more influential than animals. That’s true, if we disregard our own existence and needs.
First, free surplus energyThe energy of a system that is emitted as waste and is not part of ecosystem processes. There is always some free surplus energy as this creates the basis for evolution where new species exploit gaps in the ecosystem where free energy becomes available. Surplus energy can occur as a result of disruption or disturbance. When free surplus energy reaches More from plants will dangerously destabilise the planet without animals.
Second, it’s unfeasible for tiny animals to process energy that can be ‘farmed’ efficiently enough by a big animal like us.
Humans cannot live in the plant, bacteria and fungi domain. There aren’t enough energy hotspots to fulfil our needs. This is the role that all animals play together and it’s how animals make our planet liveable. It is also one of the missing pieces in global discussions about nature, wildlife and conservationWhy is animal conservation important? Animal conservation is important, because animals are the only mechanism to create biodiversity, which is the mechanism that creates a habitable planet for humans. Without animals, the energy from today’s plants (algae, trees, flowers etc) will eventually reach the atmosphere and ocean, much of it as carbon. The quantity of this plant-based waste is so More.
The animal domain we live in
Human beings live in the animal domain, which is built on top of the plant domain. The reason why the smallest animals evolved first, is because energy was very dilute. If you’re microscopic, you don’t need to travel very far to find enough sustenance. You’re literally bathing in it. As you get bigger, you have to move further and that takes more effort. There is a balance between your survival and where you can find food.
This is why there are many more small animals than there are larger ones. In energy terms, humans are about half way up the pyramid. If any part of this collapses, our future becomes less certain.
There are three interlocking mechanisms that make a habitable Earth and all of them are made by animals.
Transfer of energy
This is the movement of energy across the planet. It happens at every scale imaginable. If you’re reading this at night, there may be flowers opening outside, attracting insects and bats. During the day, billions of caterpillars walk from hiding spots, out onto the underside of leaves. Wildebeest continue their annual peregrinations following the emergence of fresh grass, songbirds migrate across continents and whales make their way from the Antarctic.
Migration, either daily or seasonally, follow the Sun and transfer(of nutrients) the thing that sets animals apart from plants, is that they can move. Some of the biggest migrations on Earth every day, are the movement of insects like caterpillars, from the stem of a plant to a leaf and back, before turning into butterflies and transferring the energy elsewhere. Large-scale migration of grazing animals and migratory songbirds moves More plant energy from one place to another. The biggest animals on Earth congregate in spectacular numbers and this is often where we have our richest fisheries and farming.
Amplification of energy
Amplification of energyAmplification (of nutrients and energy). Animals consume plants and other animals and in doing so, reintroduce important energy-containing nutrients back into the environment, at even higher concentrations and in patches. Amplification of energy is driven by migration and happens at every scale, from insects moving daily in and out of your vegetable patch, to African wildebeest herds and the seasonal More happens when animals move into a place and stay there for a while. Migration amplifies ecosystem energy, as millions of animals move in at springtime. They reduce and reuse the waste made by plants, that fungi and bacteria broke down into reusable nutrientsEnergy and nutrients are the same thing. Plants capture energy from the Sun and store it in chemicals, via the process of photosynthesis. The excess greenery and waste that plants create, contain chemicals that animals can eat, in order to build their own bodies and reproduce. When a chemical is used this way, we call it a nutrient. As we More over winter.
Animals are the ultimate recyclers, which lengthens the time energy is available to other animals. Animals re-use the resource as often as they can, until almost all the energy is fully consumed into food chains.
Concentration of energy in patches
Concentration happens when abundant animals continuously transfer or amplify energy in certain places. Higher up the food chainA single thread in a food web illustrating the chain of animals that eat each other. At the base of the food chain are small high-energy (fast metabolism) animals and at the other end large low metabolism animals. An example would be whales eating krill that eat plankton that eat algae. Or lions that eat gazelles that eat grass. More are also bigger animals like us. Birds, mammals, reptiles, amphibians and some insects that form heavy aggregations. The bigger the animal, the greater the concentration of waste it produces but this energy isn’t distributed randomly. It’s patchy and more importantly, those patches are just the right size and distance apart, for big-bodied animals like us.
Over tens of thousands of years, animals have developed patterns of behaviour that make these places predictable. When animals know where to find food, it keeps the quantity of dangerous and surplus plant energy to a minimum. This is how humans could evolve and until 12,000 years ago, we were part of those processes, despite having altered 95% of our environment.
Animals are essential to making our planet liveable
How do animals make our planet liveable? It’s because of wildlife that we can survive by finding enough food to eat. The role of animals in transferring, amplifying and concentrating nutrients is the very foundation for ecosystemsHow ecosystems function An ecosystem is a community of lifeforms that interact in such an optimal way that how ecosystems function best, is when all components (including humans and other animals) can persist and live alongside each other for the longest time possible. Ecosystems are fuelled by the energy created by plants (primary producers) that convert the Sun's heat energy More. Without this, human life couldn’t even exist. There is no sense in focusing on tree planting or imagining that we can beat climate change, unless we also reverse extinction and value animals as the solution, front and centre.
Spotlight
It’s not only about carbon storage by plants
This study from Frontiers in Plant Science shows the carbon cycle from a plant perspective. It’s easy to assume that capture and storage by microscopic diatoms is most relevant, because it’s the largest-scale process. But humans don’t forage at this scale. This image shows squid and mentions ‘trophic transfer’ but the article and accompanying interpretation (e.g. World Economic Forum) don’t mention the role of transfer, amplification and concentration of carbon by animals. That’s the process that creates a habitable ocean system. It’s the basis for ecosystem integrity and is therefore, the fundamental underlying mechanism for climate stability too.
