Thread by @enwudz

Follow along live with sea urchin development!

Photos and videos by @IthacaCollege in #icdevbio

Here's the first cell division - showing beautiful cytokinesis at 10X speed (from yesterday afternoon)

Here's a photo from yesterday evening. This one is nearing morula stage. 'Morula' = Latin for 'mulberry' ... what do you think? #icdevbio

Here's early morning today: after/during primary mesenchyme ingression, before invagination. Cells that eventually become the 'skeleton' of the larvae have popped out of their outer layer and into the interior of the embryo. Hard to catch these guys - they move! #icdevbio

And here is one from late morning today: invagination has begun ... gastrulation is full steam ahead! #icdevbio

Thanks to all the @ithacacollege students in #icdevbio for the photos and videos! I'll post more as I receive them.

Backing up a bit in time, here’s a video of fertilization from yesterday. The fertilization envelope raises from the surface of the egg, preventing additional sperm from entering. Thanks to @paigeram06 for the video! #icdevbio

Here’s the live view from right now - gastrulation has progressed nicely and there’s a tube running all the way through the embryo.

And here’s the same embryo in darkfield illumination

Backing up in time while waiting for videos & photos from awesome @IthacaCollege #icdevbio students ....

Here's yesterday, collecting gametes. Foregound = female urchin shedding eggs into seawater. Background right, a purplish male urchin is shedding sperm (white stuff on top)

Wrong way!!

One of the students found this urchin embryo, in which gastrulation occurred in the wrong direction - this is an example of exogastrulation.

Never seen one of these before! Super exciting!

Here we are at two days postfertilization, early pluteus larva stage. The larva has a nifty skeleton, and a rudimentary digestive system. It’s getting ready to go find some food!

Sea urchin pluteus larva in action!! Born 48 hours ago @IthacaCollege #icdevbio