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How dinosaurs, fungi, and plants evolved together
2025/2/27
I Know Dino: The Big Dinosaur Podcast
G
Garrett
S
Sabrina
Garrett: 我对恐龙与真菌和植物之间复杂关系的研究始于一个关于恐龙可能因食用真菌而产生幻觉的论点。这促使我深入研究了恐龙与这些生物之间的相互作用，以及它们对彼此的影响。本集中，我们将探讨白垩纪麦角菌的致幻特性，以及恐龙对开花植物的摄食行为，并重新审视恐龙与被子植物的协同进化。我们将探讨关于侏罗纪被子植物的争议，利用系统发育组学研究被子植物的进化，并分析可能存在于白垩纪之前的开花植物的古老花粉。此外，我们将研究白垩纪末期灭绝事件对现代雨林的影响，以及植物在白垩纪末期大灭绝后的生存状况。
Sabrina: 我将从真菌开始，因为这是本集主题的起源。真菌的形态多样，大部分生命周期以微观的菌丝体形态存在，通过分解土壤和木材获取养分。蘑菇是真菌的子实体或性器官，通过释放孢子进行繁殖，这是一种从地下营养生长到地上繁殖的奇妙生命周期。真菌的种类繁多，除了蘑菇，还包括酵母菌和各种霉菌，它们广泛应用于酿造、烘焙和奶酪制作等领域。由于真菌结构脆弱，化石记录相对较少，通常保存在琥珀中。真菌对人类的影响广泛，存在于人体各个部位，并参与细菌的控制。人类较高的体温可能是为了抵御真菌感染，因为真菌通常在较凉的环境中生长。真菌感染可引发多种疾病，从皮肤刺激到危及生命的疾病。一些真菌具有致幻特性，例如麦角菌，其产生的麦角碱被用于合成LSD。麦角菌寄生在禾本科植物上，其化石证据表明它与禾本科植物共同进化。恐龙可能食用过麦角菌感染的植物，但其影响尚不清楚。研究发现，至少有些恐龙会食用草，这基于对蜥脚类恐龙粪化石的分析。粪化石中的真菌可以帮助确定恐龙的栖息地和气候条件。对鸭嘴龙粪化石的研究表明，它们可能有意食用腐烂的木头，以获取其中的营养物质。此外，研究还发现恐龙蛋壳中存在真菌，这可能是寄生真菌在恐龙蛋壳中繁殖的结果。
Sabrina: 对被子植物的研究表明，它们可能在侏罗纪早期甚至更早的时候就已经进化出来。一项研究发现，现存被子植物谱系在侏罗纪晚期和早白垩世早期经历了快速分化。达尔文将被子植物的起源称为“讨厌的谜团”，因为它似乎在早白垩世迅速分化。然而，一些研究对早于白垩纪的被子植物的研究提出了质疑，认为许多研究未能明确定义“花”。这项研究支持被子植物在白垩纪早期快速辐射的观点。一位古植物学家开发了一种技术，可以发现数千万年前的化石花朵，这依赖于野火对植物碳骨架的保存作用。被子植物能够快速繁殖、突变和适应环境，这有助于它们在白垩纪晚期占据主导地位。被子植物与小型动物共同进化，并受益于白垩纪末期小行星撞击后的生态变化。一项研究发现，被子植物在白垩纪末期大灭绝中幸存下来，并变得更加繁盛。昆虫在被子植物的传播和占据主导地位的过程中发挥了重要作用。
Garrett: 热河鸟是最早已知的以果实为食的鸟类，这可能表明鸟类和植物共同进化。对热河鸟标本的研究表明，它可能根据季节食用不同的食物，有时食用种子，有时食用需要胃石磨碎的食物。热河鸟的脑部特征介于非鸟类恐龙和现代鸟类之间，这表明它具有较好的嗅觉和视力。一项研究发现热河鸟的消化道中含有被子植物的叶片，这进一步支持了早鸟类和被子植物共同进化的观点。中国发现了一些巨大的天坑，其中包含古老的森林生态系统，这些天坑为古老森林提供了独特的栖息地，可能包含尚未发现的物种。存在超过200种食肉真菌，它们以线虫等小型动物为食。一项研究在白垩纪琥珀中发现了食肉真菌，这表明食肉真菌在白垩纪就已经存在。
supporting_evidences
To quote from the book Molds, Mushrooms, and Medicines by Nicholas Money, which was published by Princeton University Press, quote, "...for almost all of their lives, these organisms exist as spidery colonies of tiny threads called hyphae.
When this mycelium has grown over a large area and absorbed enough food, it reverses direction and flows to the surface, where the threads merge to form mushrooms.
Think of, in addition to, you know, sauteing and washing and all that, like yeasts used in brewing and baking or cheese making or different kinds of molds.
According to that book, the entire human body is affected by fungi because fungal cells feed on our scalps, they grow in our guts, and they help control bacteria.
Another way that I've heard recently is that it's possible that the reason that we developed a higher body temperature is basically to ward off fungus.
According to that book, quote, insect attraction seems the best reason for a a mushroom to make psychedelics, though the evidence for this is slim.
There are more than 10 times more fungi than angiosperms.
Oh, I didn't realize that that was originally synthesized or extracted from a mushroom.
And when the grain is made into bread or eaten, it causes ergotism, known as St. Anthony's fire or devil's curse, because you get convulsions, vomiting, hallucinations, and pain that feels like you're on fire.
But it's not all bad because some of its compounds have been used to treat migraines and help with childbirth.
This is based on an amber fossil from Myanmar from about 100 million years ago when the earliest flowering plants and grasses were starting to evolve.
And this find helps show that grasses were established by the early mid-Cretaceous.
And it seems likely that a dinosaur could have eaten this, but it's unclear what effect it would have on a large dinosaur.
There was also a study in 2005 that found grass in coprolites, fossilized poop, of a Cretaceous sauropod.
I guess some of them did once in a while, at least.
The things you learn from fungi.
And they're irregular in shape. And there's a lot of fragmented conifer wood.
And maybe myasora ate decomposing wood and maybe got the resources or nutrients released after the fungal attack.
There was a study in 2008 and it had needle ribbon and silk like filaments.
They named it Paleo-Ufeo-Corticeps cockaphagus from Myanmar amber from the Cretaceous.
Dinosaurs may have also developed endothermy, basically being warm-blooded to fight off fungal infections.
And fungus may have driven about 200 frog species to extinction.
So you could see that really being a good way to get rid of all that fungus that might have been around them.
The difference between them is in the seeds.
The idea is that large herbivores ate cycads and conifers in the Jurassic and early Cretaceous, and they just ate a lot of plants.
A 2008 study found that sauropods probably went after conifers and ferns for nutritional and energy needs.
They became large, well-protected cones like in monkey puzzle trees.
A 2024 study found fossilized seeds in the stomach of Longeterrax, an early Cretaceous bird.
There was also a 2010 study that found gut contents of a small early Cretaceous ankylosaur found with fossilized angiosperm fruit.
You mean... covered seed plants yes not flowering plants so to kind of expand on that again angiosperms are different from gymnosperms by having an ovary which acts like a container to protect the seeds inside and it becomes a fruit so i guess plants and fungi have that in common where we kind of eat their reproductive organs yeah or kind of eating the eggs of the plants yeah a little different
The oldest uncontested fossil angiosperms are from the early Cretaceous, about 130 to 125 million years ago.
A 2024 phylogeny study found an, quote, explosive early phase of diversification of extant lineages during the late Jurassic and early Cretaceous periods.
Charles Darwin called angiosperms an abominable mystery because for a while, angiosperms appeared to originate in the early Cretaceous and just quickly diversify,
There's a 2018 study that found a flowering plant from the early Jurassic in what's now China.
They found oleanane in rock deposits hundreds of millions of years old.
Quote, with rare exceptions, these papers fail to define a flower.
So, quote, all features suggest a primary radiation.
It wasn't until Elsie Marie Friess, a paleobotanist and professor emerita at the Swedish Museum of Natural History, developed a technique to find fossil flowers that scientists found more fossilized flowers.
Heat vaporizes the moisture and plant tissue and may leave behind a black carbon skeleton, which can survive in geological strata for tens of millions of years.
They could cram more cells into leaves and be more efficient for photosynthesis, transpiration, and growth.
So angiosperms worked with small animals after the extinction, not just insects.
A 2023 study found that angiosperms came out of the end Cretaceous extinction relatively unscathed and good for them.
It's a tumbling flower beetle carrying pollen grains that belong to angiosperms, and it helped show that insects did help angiosperms dominate.
Jehalornis looked somewhat similar to Archaeopteryx, but the tail fanned out more and the head was smaller and shorter and it had shorter legs.
Birds diversified and became abundant about 135 million years ago.
They studied 90 specimens of Jeholornis because it's one of those species where there's just so many skeletons found.
They studied dozens of specimens and they compared the jaws of Jeholornis to modern birds, including species that grind seeds, species that crack seeds, and species that eat fruit.
So it was somewhere in between.
They found fossil plant phytoliths, rigid microscopic particles of silicon dioxide that form in plant tissues that in the digestive tract of a Jehalornis specimen.
There was a study from 2024 by Li Li Zheng and others that described a sinkhole.
It's a natural refuge for ancient forests, meaning it's home to species not seen anywhere else, like endangered plants and primitive forest ecosystems.
Actually, there's more than 200 described carnivorous species.
There were four fragments with fungi found, and one fragment has a piece of decomposed wood with the fungus and the trapping ring, as well as yeast cells and several nematodes.
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