When the whales walked on our primitive Earth

By Gustavo Costa von Buchwald

There was life on earth as long as the planet was cold and stable enough to support life. Before that it was a ball of fire, gases and meteorites. The times are of such magnitude, that it is difficult to understand, it is considered that for about 3,500 million years there has been life in the water or sea of ​​that time.

Evolution, mutation, change and adaptation

Not only that the types of life have been changing, but the surface of the planet has changed as well. Millions of years ago the continents were spread over the planet and they moved or floated from one side to the other. It is known that there was a supercontinent called pangea 335 million years ago, but little by little it separated and the continents became what we know today. The continents move, today, at a rate of 2.5 cm per year.

In every part of the earth there are animals. Millions of years ago, when different environments came together, mutations occurred in living beings. The oldest fossils on the planet, 400 million years ago, have been found in marine sediments.

When the environment changes, occasionally genetic changes occur and newborns have these new traits: this is called a mutation. Many of the mutations make animals less able to survive. In any case, in very special situations, they make the environment stronger and have some advantage. This process is called natural selection of species, and this is how evolution works. In short, environmental change combined with species selection has produced a great variety of life on Earth.

The Tree of Life

The idea of ​​evolution in which one living thing changes another has been known for a long time. British scientist Charles Darwin, 1809-1882, is the one who introduced with his book titled The origin of specieswhich was published in 1859, this concept of evolution.

Darwin did not envision evolution as a single line, with one animal changing to another and then another. He rather saw it as a tree full of main and secondary branches where there were several lines that branched off in different directions. Most of them went extinct, but a few carried on and survived. Each surviving branch was capable of dividing into more branches. Obviously this is based on fossil evidence, so academics look for characteristics in different animals and then fit them on a geological time scale.

the walking whales

Among the thousands of years and dozens of species that have inhabited our planet, I am going to allow myself to talk about a species that arouses respect and curiosity due to its size, the whales, the largest animal on our planet. Its heart weighs a ton, in its arteries a human could swim, its tongue is as heavy as an elephant, but its size features have only been around for the last two million years. Fifty million years ago, your ancestors looked very different.

We will begin our journey in the Eocene, with an animal the size of a cat. Scurrying along the fern-fringed bank of a tropical river in what is now Pakistan. the indohyus, which belongs to the group that evolved into whales. At that time the area was made up of swamps, deltas and lagoons and for millions of years the ancestors of the whales lived there. These whales had four legs and spent a lot of time in the water, perhaps to avoid predators. In Peru, a 43-million-year-old whale fossil was found that could still walk on land with four legs. The animal looked a bit like an otter or a beaver with a tail for swimming.

Soon in the time of evolution, thirty-five million years, the whales became completely marine. They didn’t need to live on land, so they lost the ability to walk, their weight-bearing legs gone and turned into flippers and paddles for swimming. An animal 3 meters long, the basilosaurus, thought to be a dinosaur, but fossils indicate it was a whale that already lived in the ocean. It was 18 meters long.

In fossil modernity there were two types of whales, baleen and toothed whales. These two types diverged about 30 million years ago. The beards are the big ones today. They have no teeth and feed on krill or small crustaceans. In their mouth they have cartilaginous plates called baleen where they filter the salty water with their tongue, and stay with the krill or food. The Balaeonoptera, better known as blue whalemeasures 25 meters long and is considered the largest vertebrate that has ever lived on earth.

The message I wanted to leave in this modest writing is that evolutionary processes take millions of years, something difficult to understand for modern man who has gotten used to everything quickly. And this is one of the many motives and reasons why we are destroying our planet, because we have received an environmental patrimony that has taken tens of centuries to exist, but man changes it in hours, days or months.

Nature is going to bill us for all the abuses we have committed against it. And as Stephen Hawking said:

“Humanity has a margin of a thousand years before self-destruction at the hands of its scientific and technological advances” Y “We have to leave Earth in a hundred years.” their belief that natural resources are going to be depleted very quickly due to the deterioration of ecosystems.