Evolution – Darwinism
The term Darwinism can refer to a variety of things, but often it simply means Charles Darwin’s theory of evolution. Evolution is development or change, and in biology it means the development of life. Darwin discovered the phenomenon of spontaneous mutation. In his day it was only half understood, but nowadays we all get it a little better.
The origin of DNA
About 4 billion years ago, Earth existed for half a billion years. There was still (almost) no oxygen. The atmosphere consisted mainly of carbon dioxide (CO2) and methane (CH4), there was water (H2O) and perhaps some other substances are essential for life. Amino acids and other substances were created together with energy sources such as the sun and lightning. Ultimately, the first RNA molecules were created. RNA (Ribo Nucleic Acid) is a simpler version of DNA (Desoxyribo Nucleic Acid). These complicated molecules copy themselves through a complicated chemical reaction. But sometimes a small part of that molecule changed when it was copied. This often has no obvious reason and is therefore called a spontaneous mutation. At some point, DNA emerged, and the first real cells were born.
Because every now and then an error (mutation) arose in such a DNA molecule when a single-celled organism divided, new types of cells were created. When a cell suddenly got a tail due to a mutation, with which it could move in the water, it became more successful than its ancestors. This gives you the principle of natural selection, survival of the fittest. An obsolete species or a species with a mutation that is detrimental usually dies out. Ultimately, the DNA (genes) provided information that made the organism consist of multiple cells. Now there were multicellular organisms, and the animals and plants could arise
The first plants and animals
The first plants were aquatic plants, and the first animals were anemones, sea snails and jellyfish. These animals and plants also evolved, and the more successful organisms conquered the oceans. In the meantime, land was created because the tectonic activity (plates of the earth) caused volcanism and mountains. Plants began to emerge that lived on the land and convert CO2 into oxygen (O2) through photosynthesis. The conversion of CO2 into O2 has been possible for some time, as the cyanobacteria did about 3.8 billion years ago. The atmosphere filled with oxygen. The first amphibians and other animals that could temporarily take to land soon emerged. Sharks and crocodiles also existed a long time ago. It didn’t take long for animals to live permanently on the land. There was more oxygen then than now, which is why the insects were bigger than now.
Hominids and the Beginnings of Man
Evolution continued, climate changes took place, sometimes a meteor or asteroid hit Earth. The dinosaurs, reptiles that ruled the world for millions of years, were destroyed by such an impact and the resulting climate change. The mammals took over their role. Mammals can adapt much faster and are therefore more successful. After millions of years, primates, and eventually monkeys, emerged. Evolution led to higher primates, and eventually to a monkey family tree called the Hominids.
The hominids evolved. They started walking upright, new races emerged every now and then, those races sometimes even became new species. There came a time of successive ice ages, and a species called Homo sapiens (wise or sensible man) emerged in Africa (although the continents were still different then). Scientists are not entirely in agreement, but many believe there were three hominids left at the time (some 100 million years ago): the Sapiens, the Neanderthals and the recently discovered Homo Florensis (aka The Hobbit) . It is not yet clear whether the Sapiens (also called Cro-Magnon or modern humans) were a different race or a different species from the Neanderthal. This means that it is not yet certain whether we are Homo Sapiens or Homo Sapiens Sapiens, and whether the Neanderthals were Homo Neanderthalensis or Homo Sapiens Neanderthalensis. This is because there is still a debate within biology about the definition of the term “race”. This can have quite a big consequence. If one concludes that the Neanderthals were a different race, it means that racism is not just a belief in the inferiority of people of a different skin color, but that racism can actually simply be called a belief in the divisions of humanity in races. turn into. According to biology, no other hominid races would then exist, except for the Homo sapiens sapiens. Maybe then racism would be eliminated.
There are several theories as to how the other species (or races) became extinct. It is said that the Cro-Magnons killed the Neanderthals, or that the Neanderthals simply couldn’t compete with us. Or that the two races have become mixed. It has also been shown that a major volcanic eruption occurred throughout history, and that its effects led to the extinction of almost all humans (and perhaps other hominins as well), down to a few thousand Africans.
Convergent and Divergent Evolution
Another interesting aspect of evolution is the existence of the concepts of convergent, parallel and divergent evolution.
Convergent evolution is when two species that are not or hardly related, nevertheless develop the same characteristics (both fish and dolphins are streamlined, but do not descend directly from each other or from the same ancestor). This is due to the circumstances in which they live. Many people forget that the fish did not choose to be streamlined, but that a square fish (a little exaggeration) simply dies and so the streamlined one remains. There is also the English term Evolutionary Relay. That is convergent evolution, but when the two species also lived in a different time.
Parallel evolution means that two related species develop the same. This is because the two have a lot in common and the same problems.
Divergent evolution is when two related species develop differently because they live in different conditions, even if there is only a minimal difference. This kind of evolution also has a lot to do with opportunities.
Look at Darwinism
Darwin’s theory was not so detailed at the time, but it caused quite a stir. Although Christianity already had some objections to his theory of evolution, Darwin became truly hated when he claimed that his theory must mean that man is descended from the apes. Today, however, almost everyone believes in Darwinism (except for a few ignorant ones), and it is considered an established fact. That is inevitable, because it has been shown with hard evidence that the theory of evolution is correct. What will happen to human evolution is a mystery. It is not obvious that we will become more intelligent. It is no longer the case that less intelligent people die out, because in our society almost everyone has a chance to reproduce. Evolution seems to have come to a standstill, according to some, and can only be set in motion through genetic manipulation. Perhaps we should now take over the task of nature, and we should now direct our own evolution.