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?" Says in an interview to the website 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. In fact, the question is still open. Over the years, 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 that 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 looking at 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 to just 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 feature in plants, animals (and probably also in "inferior" creatures). There are more species on Earth today 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 at the end of the dinosaur age. 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. equally,
In addition to the increase in biodiversity, the ecological complexity also increases, because more animals and plants begin to influence each other.
"The world in which the flowering plants evolved 150 million years ago was ecologically different from the world in which the ferns and conifers established themselves, which took over the world but did not diversify like the flowering plants. First, pollinators did not exist yet, and there was certainly no situation where a plant depended on a single pollinator like A Darwin's orchid that has only one moth capable of fertilizing it." says Katz.
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 are used 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 appeared of the flowering plants, 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 we haven't paid attention to until the end. 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 began to come onto land .It gives proportion to how biodiversity has developed in general."
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 perform 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 cannot imagine what they will look like in 20- 50-100 million years we come and harm the biological diversity, and reduce their chances. You can say that we also carry out the seventh extinction - we exterminate species that were made to form and actually slow down evolution.
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