The question of how life on Earth first emerged is one that humans have been asking themselves since time immemorial. While scientists are relatively confident about when it happened, there has been no definitive answer as to why it did. How did amino acids, the chemical building blocks of life, come together roughly four billion years ago to create the first protein molecules?
How did complex life arise on Earth about two billion years ago? Research by an international team of scientists from Sweden, the United States, Australia and the Netherlands now provides a new perspective on the matter. In a study published this week in Nature Microbiology, the team presents a new model about the first complex cell types that make up plants, fungi, but also animals and people. They describe how complex cellular life forms developed in evolution through the metabolic integration of simpler cell types.