Different species of a genus of starfish found on Australia's temperate east coast vary widely in their mode of reproduction. Some produce tiny eggs that develop into free-swimming larvae before becoming tiny, bottom-dwelling starfish; others have larger eggs that develop directly into starfish. Some have brood care; others cast their eggs into the sea. A study of some of these starfish, and members of a closely related genus, involved constructing a phylogeny based on mitochondrial DNA sequences, and tracing on it the different reproductive modes. The upshot gives a snapshot of how development is moulded by evolution, in the form of a kind of Hertzsprung-Russell diagram for biological stars.
