Lecture: The rise of complex life

The modern world teems with complex life — the animals, plants, fungi, seaweeds and a dazzling array of single-celled organisms known as the protists. All of these are part of the eukaryotic clade, descended from a common ancestor that lived more than 1 billion years ago. In this talk, we will provide an overview of early eukaryote evolution and the environmental context in which they evolved. We will also present new research that sheds light on the habitats in which eukaryotes lived and how they might have survived the extreme “snowball Earth” glaciations that entombed the planet in ice 720–635 million years ago (Ma). Finally, we will highlight the outstanding questions that remain, including what drove their rise to dominance during the late Neoproterozoic Era (~600 Ma).

Susannah Porter is a paleontologist who studies the fossil record of early complex life, from the oldest single-celled eukaryotes in rocks over 1.5 billion years old to the diversification of animals in 600–500 million years ago. Her research includes studies of early animal skeletons and their microstructural diversification; the role of seawater chemistry in determining skeletal mineralogy; the influence of snowball Earth glaciations on life; the oldest evidence for predation in microbial ecosystems; and the origin and diversification of the eukaryotic clade. She has conducted fieldwork on six continents, with a primary focus on the oldest fossiliferous rocks of the Grand Canyon. She is a Fellow of the Paleontological Society and the Geological Society of America, and a recipient of UCSB’s Distinguished Teaching Award.