Origins and complexity

Origin of life

Before there were cells, there were molecules. How did chemical systems begin passing useful abilities to descendants and sustaining their own reproduction?

Start with the transition from nonliving chemistry to evolving systems.

Eukaryogenesis

Complex cells with nuclei descended from simpler ancestors. How did their internal compartments, mitochondria, and distinctive cellular organization come together?

Move to the emergence of the complex cells that later gave rise to animals, plants, and fungi.

Evolution of multicellularity

Cells have repeatedly evolved into organisms that live and reproduce together. What turns a group of cells into a coherent evolutionary individual?

Explore how groups of cells become evolutionary individuals.

Origin of the genetic code

Cells translate genetic sequences into proteins. How did a code and the machinery that reads it arise together?

Origin of viruses

Viruses have remarkably different genomes and structures. Did their major lineages emerge independently, and from what ancestors?

Biological homochirality

Life predominantly builds proteins and nucleic acids from particular mirror-image forms. How did those molecular preferences become established?

Cambrian explosion

Animal body plans diversified rapidly around the Ediacaran–Cambrian transition. What combination of changes drove that radiation?

Rangeomorph nutrition

Rangeomorphs were branching Ediacaran organisms. How did they obtain nutrients in the deep-sea settings where some lived?

Great Ordovician Biodiversification Event

Marine diversity expanded dramatically around the Ordovician. How did ecological change, nutrient cycling and climate interact to produce that diversification?

De novo gene birth

New protein-coding genes can arise from DNA that did not previously encode a protein. Which ones become useful and persist through evolution?