flowchart LR M["Metazoa"] --> C["Cnidaria"] M --> B["Bilateria"] C --> AN["Anthozoa<br/>corals, anemones"] B --> P["Protostomia"] B --> D["Deuterostomia"] P --> LO["Lophotrochozoa"] LO --> MO["Mollusca"] MO --> BI["Bivalvia<br/>oysters, clams, mussels"] D --> EC["Echinodermata"] EC --> AS["Asteroidea<br/>sea stars"] EC --> EH["Echinoidea<br/>sea urchins"] D --> CH["Chordata<br/>vertebrates, including us"]
Start Here
The animals this lab works on, and why they are built the way they are
The modules teach you to handle the data. The Lab Conceptual Framework tells you how the lab interprets it. This section covers the part in between that is easy to assume and expensive to skip: what these animals actually are.
If you have found yourself reading “metamorphosis competency” or “gene body methylation tracks calcification” and quietly not knowing what a pediveliger is, or why a coral needs an alga to live, you are in the right place. Nothing here assumes a background in invertebrate zoology.
Three phyla, one lab
The lab’s study animals come from three phyla that are not close relatives. This matters more than it first appears — it means shared responses to a stressor are unlikely to be shared by descent, and are more likely to reflect convergent solutions to the same problem in seawater.
The single most useful orienting fact on that tree: a sea star is more closely related to you than it is to an oyster. Echinoderms are deuterostomes, on our branch. Bivalves are protostomes, on the other one. Corals split off before either.
What each group brings
Bivalves — oysters, clams, mussels. Molluscs with a two-part hinged shell, no head to speak of, and gills that do double duty as respiratory surface and feeding apparatus. Sessile or nearly so as adults, filter-feeding, and the backbone of shellfish aquaculture. Most of the lab’s work lives here.
Echinoderms — sea stars, sea urchins. Pentaradial as adults but bilateral as larvae, moving on a hydraulic water vascular system with no direct analogue anywhere else in the animal kingdom. Urchin embryos are among the most thoroughly described in developmental biology; sea stars matter to the lab additionally as keystone predators undergoing a mass mortality event.
Cnidarians — corals. Two tissue layers, radial symmetry, no organs in the sense the other two have them, and a nutritional dependence on dinoflagellate symbionts living inside their own cells. A coral colony is a partnership, and most of what stresses a coral stresses the partnership first.
What they have in common
Despite the phylogenetic distance, the three groups converge on a set of traits that shape every experiment the lab runs:
- Broadcast spawning and planktonic larvae. Gametes go into the water column, fertilization is external, and development happens as free-swimming larvae before settlement. This is why early-life exposure windows are so short and so consequential.
- Calcification. All three build calcium carbonate structures — which is why ocean acidification is a shared threat, and why calcification is a shared physiological readout.
- Innate immunity only. No antibodies, no lymphocytes, no adaptive immune memory in the vertebrate sense. Whatever “immune memory” means in these animals, it is not the mechanism you learned in an immunology course.
- Sessile or sedentary adults. They cannot leave. An organism that cannot escape a stressor has to solve it physiologically, which is precisely what makes these animals informative about environmental memory.
That last point is the through-line connecting this section to the rest of the site.
How to use this section
Read Cross-Cutting Themes first if you want the fastest orientation — it covers the shared biology in one pass. Read the taxon pages when you need depth on the animal in front of you.
| Page | Read it when |
|---|---|
| Bivalves | Working on oysters, clams, or mussels — most lab projects |
| Echinoderms | Working on sea stars or urchins |
| Cnidarians | Working on corals or symbiosis |
| Cross-Cutting Themes | You want the shared biology, or you are new and want one page |
| Glossary | You hit a term and need it defined now |
| Reading List | You want to go deeper than these pages go |
Each taxon page follows the same structure, so once you learn the shape on one, you can skim the others.
TipWhere this connects
The genomic resources sections on each taxon page list the reference assemblies used in the technical modules — including the Crassostrea virginica assembly you annotate in the NCBI BLAST module. If you want to know what the sequences you are BLASTing actually came from, start there.