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Our origin

Two million years and beyond

Our human ancestors of so long ago are considerably smaller than we are and walk less upright. A full-grown adult is no taller than a twelve-year-old in our time. Their arms are longer, their faces are more ape-like and they have more hair. Unlike apes, who live in the middle of the woods, swinging from branch to branch, humans live at the border, closer to the open fields. They may go hunting in groups or look for half-eaten carcasses left behind by predators. They make more gestures and use a larger variety of different sounds than apes and they look us more directly in the face, and give us a peculiar sense of kinship.
Humans and the present apes (chimpanzees, orangutans, gorillas and bonobos) are different species, developed from a common ancestor. The common ancestors of apes and humans had in their turn ancestors, from which all the mammals originated, and they were preceded by the ancestors of all living beings: animals as well as plants.

When we observe apes and monkeys in the zoo or in the wild, we experience the common roots we share with them: they play and tease, try to dominate each other, care for their kids and have sex. And don't we have a similar experience with cats and dogs? We must be related to them, even if that goes back two hundred million years ago. There is a mutual understanding and shared needs for food, sleep, company and curiosity about new and interesting things.
Human origin; mamals dominated by dinosaurs

The origin
Two million years is only a short time compared with the history of life. Sixty-five million years ago, the last big dinosaurs walked the earth. They had been the dominant species for maybe two hundred million years. The early mammals of this period had to live and hide in places where the dinosaurs and others couldn't come. Mammals were much smaller at that time: the saber tiger has an ancestor the size of a mouse, and elephants have ancestors as small as pigs.
After the dinosaurs became extinct, mammals, the predecessors of mice and cows, horses and dogs, monkeys and humans, gradually grew bigger and smarter.

Human origin; goes back to the stellar systems We can go back further in time, along an uninterrupted genetic line of births from you and me to the very first mammals and beyond. Sexual reproduction is much older than the mammals: birds and fish and snails and roaches and bugs and plants do it. Sexual reproduction goes back more than a billion years. Before that there was no sexual reproduction, but only cell division (cloning), in which the mother cell divided itself into two identical daughter cells. The cells of our body still reproduce themselves that way, when we grow from an embryo in the womb to an adult ('full-grown') individual. It is also seen in the growth of our nails, hair and new skin.
The only cells that do not clone themselves are our sex cells (sperm cells in males and egg cells in females). They must combine with each other to make a new individual. As the male and female cells fuse together, the genetic properties are combined, so that the new individual has properties of both and is also a little different from both. Sexual reproduction has thus brought forth an enormous variety of different species of plants and animals, of which humans are the most complex and advanced.

Going further back in time, the question comes up: how did life first start? Three or four billion years ago, large strings of protein molecules (protein still forms the basis of all life forms) somehow started to divide themselves. Those large protein molecules were composed of smaller molecules, which are built from atoms of hydrogen, oxygen and carbon. They, in their turn, consist of elementary parts (quarks and electrons) which are the smallest known building blocks of the universe. So ultimately we are composed of the same matter as all other living beings and all other matter around us. And in the end we will decompose again when we die (individually) or begome extinct (as a species).