Human Evolution – A Very Short Introduction

Many of the important advances made by biologists in the past 150 years can be reduced to a single metaphor. All living, or extant, organisms, that is, animals, plants, fungi, bacteria, viruses, and all the types of organisms that lived in the past, are situated somewhere on the branches and twigs of an arborvitae or Tree of Life. We are connected to all organisms that are alive today, and all the organisms that have ever lived, via the branches of the Tree of Life (TOL). The extinct organisms that lie on the branches that connect us to the root of the tree are our ancestors. The rest, on branches that connect directly with our own, are closely related to modern humans, but they are not our ancestors.  The ‘long’ version of human evolution would be a journey that starts approximately three billion years ago at the base of the TOL with the simplest form of life. We would then pass up the base of the trunk and into the relatively small part of the tree that contains all animals, and on into the branch that contains all the animals with backbones. Around 400 million years ago we would enter the branch that contains vertebrates that have four limbs, then around 250 million years ago into the branch that contains the mammals, and then into a thin branch that contains one of the subgroups of mammals called the primates. At the base of this primate branch we are still at least  50–60 million years away from the present day.

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About Giorgio Bertini

Director at Learning Change Project - Research on society, culture, art, neuroscience, cognition, critical thinking, intelligence, creativity, autopoiesis, self-organization, rhizomes, complexity, systems, networks, leadership, sustainability, thinkers, futures ++
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