Comprehensive coverage

Why did the flowering plants suddenly take over the earth a short geological time ago?

Dr. Ofir Katz The Dead Sea delivery of Dead Sea and Arava Science Center Recently published an article in the journal Annals of botany who tries to answer this riddle. The answer to his words depends on the feature of evolution to create an increasing variety of species over time, and he also has something to say about the sixth extinction - man-made

"How did it happen that the flowering plants, which evolved the latest from an evolutionary point of view, make up 90% of all land plant species we know today?" Photo: Bernard DUPONT.
"How did it happen that the flowering plants, which evolved the latest from an evolutionary point of view, make up 90% of all land plant species we know today?" Photo: Bernard DUPONT.

"How did it happen that the flowering plants, which evolved the latest from an evolutionary point of view, make up 90% of all land plant species we know today?" Says in an interview to the site the scientist Dr. Ofir Katz of the Dead Sea Branch of the Dead Sea and Arabah Science Center. Dr. Katz Recently published an article in the journal Annals of Botany, a journal published by the University of Oxford that is considered one of the oldest journals in the field of plant sciences and botany. In the article, Katz tries to answer this riddle, while examining the overall sequence of evolution, and not just that of the plants themselves.

"Darwin was the first to put the riddle on the agenda, but was unable to solve it. Actually the question is still open. Over the years, many, many theories have been created, some more well-founded, some less so. In the article I show that we know most of what we need to know to answer the question, but we look at things in a suboptimal way." says Dr. Katz.

The flowering plants appeared for the first time about 140 million years ago, in the middle of the time of the dinosaurs, who fed mainly on ferns and needles. Shortly after their appearance they have already filled every possible ecological niche. According to Katz, fossils found in the steppe from that period showed that the vegetation there was dominated by plants with flowers shortly after they first appeared.

So far, the researchers trying to answer the question of the origin and early evolution of the flowering plants have examined the plant world since their appearance 150 million years ago to 50 million years ago. "I suggest examining the broader picture, which includes everything that has happened in the last 450 million years, more or less since advanced multicellular organisms began to appear, and not limit ourselves only to plants."

In other words, Katz suggests looking for the broader context, not only between the herbivores and the plants themselves but everything around them. It turns out that the concept according to which biodiversity recovers after a mass extinction is not correct. Biodiversity increases with each development of a new trait in plants, animals (and probably also in "inferior" creatures). Today there are more species on Earth than there were 100 million years ago, and 100 million years ago there were many more species than 300 years ago. The younger a group, the more diverse it is. A good example of this are the birds and mammals that established themselves on Earth with the end of the age of dinosaurs. There are more species of birds and mammals than there were species of dinosaurs at their peak, and there were more species of dinosaurs than amphibians when they ruled the earth. the same size,

In addition to the increase in biodiversity, the ecological complexity also increases, because more animals and plants begin to influence each other.

"The world where the flowering plants evolved 150 million years ago was ecologically different from the world where the ferns and conifers established themselves, which took over the world but did not diversify like the flowering plants. First, pollinators didn't exist yet, and there certainly wasn't a situation where a plant depended on a single pollinator like Darwin's orchid that only had one moth capable of fertilizing it." says Katz.

It turns out that the concept according to which biodiversity recovers after a mass extinction is not correct. Biodiversity increases with each development of a new trait in plants, animals (and probably also in "inferior" creatures). Today there are more species on Earth than there were 100 million years ago, and 100 million years ago there were many more species than 300 years ago. The younger a group, the more diverse it is. You can see that there are many more species of butterflies, which evolved together with the seed-covered plants, compared to scorpions - a much older group. Photo: Böhringer Friedrich, Wikimedia.
It turns out that the concept according to which biodiversity recovers after a mass extinction is not correct. Biodiversity increases with each development of a new trait in plants, animals (and probably also in "inferior" creatures). Today there are more species on Earth than there were 100 million years ago, and 100 million years ago there were many more species than 300 years ago. The younger a group, the more diverse it is. You can see that there are many more species of butterflies, which evolved together with the seed-covered plants, compared to scorpions - a much older group. Photo: Böhringer Friedrich, Wikimedia.

The coal connection

As proof of this, Katz brings the coal - remains of trees from a period about 350 million years ago when there were very few plant eaters on the land and there were no fungi capable of breaking down cellulose. As a result, when these trees died, they did not decompose and their remains became the coal that we burn in the power plants.

On the other hand, 150 million years ago the picture was completely different, Katz explains that an evolutionary race arose between the plant-eating animals and their 'prey', because the plants also had to defend themselves against their eaters. But the animals also return their organic matter to the soil when they die and serve as fertilizer for the next generation of plants. The seed covered plants also recycled themselves well due to their short lifespan.

"We see time and time again in evolution that when a new and useful feature appears, it becomes widespread, and then more and more species with this feature develop, until after a period a uniform, slow pace is reached until the next revolution occurs in the same evolutionary branch. 150 million years ago, when the first features of the flowering plants appeared, they already found themselves in a rich and complex environment with many factors that accelerated evolution. The result is a very large variety of species even today."

"In my opinion, this is the point in the story that has not yet been fully considered. The main contribution of the article I published is that it changes the time scale and the biological scale. Instead of looking at plants 150 million years ago we need to look at all land creatures since they first came onto land. It gives a proportion to how biodiversity in general has developed."

Like all life on earth, plants also experienced periods of extinction such as the one in which the dinosaurs were destroyed, however according to Dr. Katz, plants with flowers were less affected because their seeds can survive in the soil for long periods of time.

Now we are at the height of the sixth mass extinction, the one caused by man, what is the effect of this extinction?

"We are destroying biological diversity that has painstakingly developed step by step for over 400 million years, at least on land. More than that, apparently there are critical points in the evolution of certain groups - their early stages. Today we have groups that we are at the beginning of their evolution, for example C4 plants that can carry out photosynthesis more efficiently, the best known of which is millet. The reason it thrives is that it is able to photosynthesize more efficiently than wheat or rice. These plants appeared tens of millions of years ago but their big breakthrough was in the last 10-20 million years. Precisely at the critical stage in the evolution of what may be new groups of organisms that we are unable to imagine what they will look like, that may dominate the world in 20-50-100 million years, we come and harm the biological diversity, and reduce their chances. It can be said that we are also carrying out the seventh extinction - we are exterminating species that could have been created and actually slowing down evolution.

See more on the subject on the science website:

Leave a Reply

Email will not be published. Required fields are marked *

This site uses Akismat to prevent spam messages. Click here to learn how your response data is processed.

Skip to content