To many, Anurida maritima are the clusters of blue specks in rocky tide pools. Upon closer inspection, these specks are intertidal arthropods, with the ability to survive periods of high-tide submersion thanks to their hydrophobic hair and cuticle.

Here in the Dunn lab, siphonophores are our favorite animal and the focus of much of our research. Dr. Phil Pugh is a good friend of the lab, and he also happens to have described more new species of siphonophores than anyone who has ever lived. In the video below, he describes what it’s like to come across a siphonophore in the deep sea with a submarine. What looks like one long body in this video is actually a free-swimming colony of clones — many genetically identical bodies that are all attached. But each body in the group isn’t just like its neighbor. They each do a specific job for the colony. Some individuals will swim, some will catch food, and some will reproduce.

Robert Sandler tells the story of doliolid reproduction. The video was made with paper puppets and hand-drawn animations. Robert made this episode with support from the Society of Royce Fellows.

Connor McGuigan, an invertebrate zoology student, describes Astrammina rara: a giant, carnivorous cell that lives in Antarctic waters. This foraminiferan is a unicellular organism that can capture and eat animals much larger than it.

Riley Thompson, from the College of the Atlantic, tells the story of how animals become invisible.

In this video, Trisha Towanda talks about one particular jellyfish, the fried egg jelly, and some of the other creatures that hang around it. There are moon jellies that the fried egg jelly eats. These moon jellies have little parasitic crustaceans on them called amphipods, which jump to the fried egg jelly while the moon jelly is being eaten. There are also crabs that ride around on the fried egg jelly, that are parasitic in their youth, but then grow to be helpful symbionts by eating off the little amphipods. This sort of coming of age story, where a symbiont’s relationship changes over its lifespan is an unusual one. Trisha put the pieces together by staring at them for hours and days and weeks when she was in Erik Thuessen‘s lab at Evergreen State College.

If you are stuck to a rock it is tricky to get close enough to a partner to mate. One solution to this problem would be to release eggs or sperm into the open water, which is what many animals in this situation do. Acorn barnacles (Semibalanus balanoides), however, found a different solution. They have evolved the longest penis relative to their body size of any animal. In this video the penises of several barnacles are probing the neighborhood for mates. The penis is re-grown each mating season.

Sophia Tintori and Cassandra Extavour talk about the evolution and development of multicellular organisms, and in particular the specialization of reproductive cells.

Riley Thompson made this animation about the fascinating lifecycle of narco babies. We usually don’t think of babies that grow inside their mothers as parasites, but sometimes the lines get very blurry. This is especially true in Narcomedusae, a group of poorly known jellyfish found throughout the world’s oceans.

Robert Sandler tells the story of ocean slime, using stop motion and jellyfish puppets. Robert made this episode with support from the Society of Royce Fellows.

This video demonstrates some of the features of PhyloTree. It then shows the early explosive discovery of mammal species (most major mammal groups were discovered early on), and then shows the slow and steady discovery of cnidarians (many cnidarians remain to be described). The tool can also be used to quickly find the first species that was described in a group. The first siphonophore to be described, for example, was Physalia physalis (the Portuguese man o’ war).

Alysse Austin, a student in Casey Dunn’s Invertebrate Zoology course at Brown University, describes sexual dimorphism in green spoonworm.

Here is a semi-interactive video (with the option of a single, non-interactive video here) from CreatureCast alum Sophia Tintori, featuring tips from a handful of ocean-dwellers that each have drastically different approaches to being invisible.

In this first video, Alison Sweeney talks about work that has been done in the Morse lab on Squid iridescence.

Unlike some other textbooks, this one does not follow a top-down narrative. Rather it has the flow of a conversation, with backtracking. We will often build up programs incrementally, just as a pair of programmers would. We will include mistakes, not because I don’t know the answer, but because this is the best way for you to learn. Including mistakes makes it impossible for you to read passively: you must instead engage with the material, because you can never be sure of the veracity of what you’re reading.

The main programming language used in this book is Racket. Like with all operating systems, however, Racket actually supports a host of programming languages, so you must tell Racket which language you’re programming in.

This textbook has been used in classes at: Brown University, Cal Poly, Columbus State University, Northeastern University, NYU, Reed College, UC-San Diego, UC-Santa Cruz, University of Rhode Island, University of Utah, Westmont College, Williams College, and Worcester Polytechnic Institute.