Evolution of fungi

Fungi have lived on Earth for a very long time.

They likely started out living in water. Some early fungi had tiny tails to help them swim. Later, they moved to live on land.

Long ago, fungi might have been the most common life on Earth. They grew very fast when many plants and animals died. This helped them turn old things into food for the ground. Fungi are amazing helpers for our world.

Fungi have been on Earth for a very long time. DNA studies show they came from a common ancestor. This ancestor lived at least 1.2 billion years ago.

Early fungi likely lived in water. They had flagella, which are tiny tails used to swim. Most fungi do not have these tails today.

Some fungi moved to live on land. A fossil named Ourasphaira giraldae may have lived on land a billion years ago. This was long before plants lived on land. Fungi might have even helped add oxygen to the air.

Fungi are hard to find in fossils. This is because their parts are often soft and small. They rot easily. However, we do find them in rocks like the Rhynie chert.

Fungi can become very common after big changes. About 251 million years ago, they were very abundant. They may have been the main life form on Earth. After many plants and animals died, fungi grew very fast. This was like a massive compost heap. They used the dead things to grow.

Fungi are a unique group of living things. They are not plants or animals. They belong to their own special kingdom. Scientists use DNA to study how they changed over time. This DNA shows all fungi come from one common ancestor. This ancestor lived at least 1.2 to 1.5 billion years ago.

Many early fungi probably lived in the water. These early fungi had flagella. A flagellum is a tiny tail used for swimming. Most fungi today do not have these tails. They lost them as they changed over time.

Moving from water to land was a big change. This required new ways to get food. Some fungi became parasites that live on others. Others became saprobes that eat dead things. Some even formed helpful partnerships called mycorrhiza. These partnerships help plants grow.

One fossil found in the Canadian Arctic is named Ourasphaira giraldae. It may have lived on land one billion years ago. This was much earlier than scientists once thought. It lived long before plants moved onto land.

Finding old fungi in rocks is a hard job. Most fungi do not make hard parts like shells. Their bodies are often soft and fleshy. This means they rot away very quickly. Many fungal structures are also very tiny. This makes them hard to see in fossils.

Scientists often find them inside fossils of plants or animals. They use special tools like light microscopy to see them. They also use acid to dissolve rock around a fossil. This helps them see the small details on the surface.

Fungal fossils become more common in the Devonian period. This was between 416 and 359.2 million years ago. In a place called the Rhynie chert, fossils are abundant. During this time, different groups like Ascomycota and Basidiomycota split apart.

About 90 million years ago, the first mushrooms appeared. These were called Archaeomarasmius legletti. They were found in amber. Other fossils like Prototaxites may have been very tall organisms. They lived during the late Silurian period.

Fungi can grow very fast when the world changes. About 251 million years ago, there was a huge spike in fungi. They may have been the main life form on Earth then. They also grew a lot 66 million years ago. This happened after many plants and animals died out.

Scientists say this was like a massive compost heap. The dead things provided plenty of food for the fungi. This allowed them to flourish while other life struggled. Fungi are very good at surviving these big changes.

Fungi represent a distinct kingdom of life that is separate from both plants and animals. Scientists use DNA analysis to trace their evolutionary history. This genetic evidence shows that all fungi descended from a single common ancestor. This ancestor likely lived between 1.2 and 1.5 billion years ago.

While many early fungi likely lived in aquatic environments, new evidence suggests they may have been on land much earlier than once thought. For example, a fossil named Ourasphaira giraldae from the Canadian Arctic might have lived on land one billion years ago. This discovery suggests fungi colonized land long before plants arrived.

Early fungi likely lived in water and possessed flagella. A flagellum is a tiny, whip-like structure used for swimming. During the Paleozoic Era, which lasted from 542 to 251 million years ago, many fungi were aquatic. These organisms were similar to modern Chytrids because they used flagellum-bearing spores to move. Over time, most fungal lineages lost the flagellum as they adapted to new environments. Moving from water to land required fungi to develop new ecological strategies. They evolved into saprobes that eat dead organic matter and parasites that live on other organisms. They also developed mutualistic relationships, such as mycorrhiza, which are helpful partnerships with plants.

Finding fossils of fungi is a significant challenge for paleontologists. Unlike many animals, fungi do not biomineralize, meaning they do not create hard shells or bones. Most fungal structures are microscopic or consist of soft, fleshy tissues that decay quickly. This makes the fungal fossil record much more meager than the records for plants or animals. To find them, scientists often look for fungi preserved within a plant or animal host. They use thin-section preparations to study these samples under light or transmission electron microscopy. Researchers also use acid to dissolve the surrounding rock in compression fossils. This process allows them to see tiny surface details using scanning electron microscopy.

Fungal diversity grew significantly during the Devonian period, between 416 and 359.2 million years ago. The Rhynie chert provides a rich record of fungi from this era, including Zygomycota and Chytridiomycota. Around 400 million years ago, the Ascomycota and Basidiomycota lineages diverged from one another. By the Late Carboniferous period, roughly 318 to 299 million years ago, all modern classes of fungi were already present. Some organisms, like Prototaxites, may have been the tallest living things during the late Silurian period. These were likely fungi or lichens that grew very large.

Specific groups of fungi appeared at different points in Earth's history. Lichen-like fossils have been found in the Doushantuo Formation in China, dating back 635 to 551 million years ago. The oldest known fossil of a sporocarp, or a spore-bearing structure, is a species called Paleopyrenomycites from the Rhynie Chert. Much later, the first known mushroom-forming fungi appeared. A species named Archaeomarasmius legletti was found preserved in amber. This fossil dates to the mid-Cretaceous period, approximately 90 million years ago. This shows that while fungi are ancient, the familiar mushrooms we see today are relatively recent.

Fungi show incredible resilience during major biological crises. About 251 million years ago, following the Permian-Triassic extinction event, a "fungal spike" occurred. This was an extraordinary abundance of fungal spores in the sediment. During this time, fungi may have been the dominant life form on Earth. They also experienced a massive bloom approximately 66 million years ago. This occurred immediately after the Cretaceous-Tertiary extinction event. When many plant and animal species died out, the Earth became a massive source of organic matter. Scientists have described this period of fungal growth as being like a massive compost heap.

The ability of fungi to flourish during these times is linked to their role as decomposers. When large-scale deforestation or mass extinctions occur, they provide a sudden wealth of nutrients. This allows fungi to expand rapidly while other life forms struggle to survive. Molecular data supports this resilience, as phylogenetic analyses of over 5,000 agaricomycete species show no sign of a mass extinction at the Cretaceous-Tertiary boundary. While other kingdoms faced collapse, fungi utilized the changing environment to thrive. This connection between fungal evolution and global ecological shifts highlights their vital role in Earth's systems.