DEVELOPMENT: Same Difference: Sea Urchins or Starfish

Sea Urchins as a Model System for Studying Embryonic Development

Developmental biology is the scientific discipline primarily concerned with embryogenesis, the process by which a single cell (the fertilized egg) gives rise to a multicellular organism. Since the emergence of this field as an experimental science in the late 19th century, biologists have relied on a relatively small number of model organisms, each possessing certain distinctive and useful char...

Phylogeny and development of marine model species: strongylocentrotid sea urchins.

The phylogenetic relationships of ten strongy-locentrotid sea urchin species were determined using mitochondrial DNA sequences. This phylogeny provides a backdrop for the evolutionary history of one of the most studied groups of sea urchins. Our phylogeny indicates that a major revision of this group is in order. All else remaining unchanged, it supports the inclusion of three additional specie...

Can sea urchins beat the heat? Sea urchins, thermal tolerance and climate change

The massive die-off of the long-spined sea urchin, Diadema antillarum, a significant reef grazer, in the mid 1980s was followed by phase shifts from coral dominated to macroalgae dominated reefs in the Caribbean. While Diadema populations have recovered in some reefs with concomitant increases in coral cover, the additional threat of increasing temperatures due to global climate change has not ...

REpROdUCTIvE ISOLATION BETwEEN SpECIES OF SEA URChINS

Existing knowledge on reproductive isolating barriers between sea urchin species is reviewed. Experiments involving artificial production of hybrids between congeneric echinoid species have shown that in most cases hybrids are viable and capable of backcrossing. Only species separated for > 5 million yrs show complete post-zygotic isolation. Each potential prezygotic isolating barrier appears t...

Pentamerism and Modularity in Sea Urchins