This morning I went here (see arrow): See how it’s covered in water? I took this picture at about 13:00, probably right at high tide. And of course when I was out there this morning at 06:00, it was low tide. It wasn’t the greatest of low tides but it allowed me to see what…
Tag: marine invertebrates
Graduation Day
Today was a big day for me. I got to graduate some of my baby urchins from glass slides onto coralline rocks. They were growing very quickly on the slides, chowing down on scum faster than I can grow it, so now it’s time for the biggest ones to really put their Aristotle’s lanterns to…
Hitting the wall
We humans use the term “hitting the wall” when we find ourselves in situations in which progress is elusive despite extreme effort. For endurance athletes or anyone doing any serious physical training it can mean not being able to break one’s personal best time for a race, or not being able to continue getting measurably…
Eating, pooping, and turning over
My baby urchins have become scum-eating machines! They are 88 days old now and I am beginning to wonder if I can generate scum fast enough to keep up with them. I did a head count this morning and have three bowls, each of which holds a population of ~100 urchins, and a bowl that…
Symmetries II
Most of the animals that we are familiar with (think of any pets you’ve ever had) have bilateral symmetry: they have a head end and a tail end, a left and a right, and a top and a bottom. In scientific terms that translates to the anterior-posterior, left-right, and dorsal-ventral axes. Also, most bilateral animals…
And. . . we have mouths!
Finally! At long last I have evidence that my juvenile urchins have mouths and are feeding. A week ago I put a batch of seven teensy urchins onto a scuzzy glass slide and have been watching them daily ever since. And yesterday, just as I was beginning to worry that they’d never be able to…
Oral examination
Anyone who went to graduate school in the sciences remembers what oral exams are like. I remember not having any fun at all in mine, and by the time I was dismissed I wasn’t sure what my own name was. Fortunately, that is all ancient history and now I get to spend my time performing…
Next step: Building a mouth
My oldest baby urchins have been actual sea urchins for eight days now. Their total age, counting from the time they were zygotes, is 58 days. When an animal undergoes a life history event as drastic as this metamorphosis, it can be tricky deciding how to determine its age. Do you count from when egg…
Learning to walk
Imagine spending your entire life up in the water column as a creature of the plankton. You use cilia to swim but are more or less blown about by the currents, never (hopefully!) encountering a hard surface, and feeding on phytoplankton and other particulate matter suspended in the water. Then, several weeks into your life’s…
Taking their sweet time
After much teasing and titillation, my urchin larvae have finally gotten down to the serious business of metamorphosis. It seems that I had jumped the gun on proclaiming them competent about a week ago, or maybe they were indeed competent and just needed to wait for some exogenous cue to commit to leaving the plankton for…