Question

When a sea cucumber feels threatened, which of the following are likely defense mechanisms?

Select one:

a. they eject their (toxic) intestines from their bodies

b. shriveling up so they look like unappetizing raisins

c. they puff up to look big, and inflate their spikes hydrostatically

d. they get out their pepper spray

In the waters off the coast of California, large groups of sea urchins often come together to eat this organism _______, often decimating its population in a matter of weeks or months, and allowing for a whole new community of animals to colonize, including ________

Select one:

a. giant kelp; brittle stars, sea stars, and dollars, and sea cucumbers

b. zooxanthelle (a symbiont with coral); sharks, eels, and clownfish

c. brittle stars; crabs, snails, and coral

d. giant kelp; lobster, eels, and sharks

Feather stars have existed for at least 440 million years, and are abundant in the fossil record (you might even be able to find some in Richmond next time you're there!). At least _____species are found in the fossil record.

Select one:

a. 1000

b. 1700

c. 100

d. 10

e. 5000

Answer 1

Answer 1. a. They eject their (toxic) intestines from their bodies.

Sea cucumbers can regenerate the expelled viscera within a few weeks.

Answer 2. a. giant kelps; brittle stars, sea stars and dollars, and sea cucumbers.

This happens due to the absence of the urchins' natural predators, the otters, which are a keystone species which helps maintain the kelp forests. Thus urchins are able to dessiminate entire forests of kelps, leaving behind 'urchin barrens'.

Answer 3. e. 5000

Although only about 600 species survive, feather star fosssil records indicate that at least 5000 extinct species have been there.