Fungi through the ages

Compared to the Plant and Animal Kingdoms, the Fungi Kingdom is fairly unchartered territory in the world of science. It wasn’t until the mid-20th century that fungi were designated their own Kingdom in taxonomy, previously having been considered part of the Plant Kingdom. 

As it turns out, fungi are vastly different to plants. Surprisingly, fungi are more closely related to humans than you’d assume, sharing a common ancestor around 1.3 billion years ago. This also means that humans are more closely related to fungi than to plants.  

With more than 90% of fungal species still unknown to science, there’s a lot we don’t yet know about fungi. Research into fossil records paints an intriguing story of how fungal life on earth may have evolved, but what does the evolutionary story of this remarkable Kingdom tell us? 

 

500 million years ago: Plants and fungi team up 

The first plants to colonise land on Earth, approximately 500 million years ago, were mosses, liverworts, and hornworts. 

We are not certain exactly how these early plant ancestors emerged from the sea to thrive on land, but it's thought that fungi played a crucial role. It is widely believed that these pioneering plants must have relied on symbiotic relationships with fungi to get the nutrients they needed to survive on hostile, barren land. 

We know that fungi are vital to modern ecosystems, but this means they might have played a more important role than we ever imagined in the evolution of plant and animal life on planet Earth.

 

The first plants to colonise land on Earth were mosses, liverworts, and hornworts.

 

430 million years ago - Giant fungi rule the Earth 

Giant fungi sound spooky, right? Ancient fossils known as Prototaxities suggest that during the Devonian period (around 430 million years ago) a forest of giant structures loomed over the limited plant life existing on land. At up to eight metres tall and one metre wide, they were the largest terrestrial organisms of the time, before large woody plants such as trees existed. It’s now widely accepted in science that these structures were actually huge fungal organisms.

 

Fungi today 

Fungi are hugely diverse - the second largest Kingdom after animals, with an estimated 2,500,000 species - and can be found in every corner of the planet, from the bottom of the deep seas to Antarctic glaciers, to the stratosphere on the edge of our planet.  

Although plants and animals now dominate the land, fungi are our unseen heroes, supporting all life on Earth.  

Over 90% of plants rely on mutually beneficial relationships with fungi (mycorrhizal fungi, which are associated with plant roots, and endophytic fungi, which live within plants).  Mycorrhizal fungi help plants take up water, provide nutrients, and protect them against pests and drought. In return, plants provide the fungi with sugars from photosynthesis. Endophytic fungi live in the roots, shoots and leaves of plants. They can support plant growth and improve resistance to stresses such as disease or drought.

 

Chanterelle forms mycorrhizal associations with trees including oak, birch and pine.

 

Fungi can be tiny and invisible: one teaspoon of soil can contain hundreds of fungal species. But they can also be immense: the largest organism on Earth is not the blue whale or giant redwood tree, but thought to be an individual of the dark honey fungus, Armillaria ostoyae, in the forest of Oregon, recorded as extending across more than 10 km2!  

Fungi are also vital for ecosystems because many of them decompose organic matter.  Fungi called ‘saprotrophs’ break down dead and decaying matter to obtain nutrients. In doing so, they cycle carbon and nitrogen back into the soil for other organisms to use.  

 

 

We can also thank fungi for delicious food sources (mushrooms, but also fermented food and drink), and medicines (such as the antibiotic penicillin). 

A fungi future 

Fungi underpin all human life on earth, but they’ve more to give! 

Fungi might be our biggest aid in combating food insecurity, pollution and climate change. Scientists are developing how different fungal species can be used to make sustainable clothing, building materials, clean polluted sites and plastic waste, in addition to being used as eco-friendly biopesticides and biofertilisers in agriculture.  

With roughly 95% of fungi yet to be scientifically described, there’s still realms of unearthed potential to be discovered. Who knows how these present-day wonders will change the future of humankind.

 

Some fungal species can degrade plastics and help reduce plastic pollution