Exam 1 - Cnidarians Flashcards Preview

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Flashcards in Exam 1 - Cnidarians Deck (20):
1

What does cnidaria mean in Greek?

nettle.

2

Where do you find cnidarians?

entirely aquatic, mostly marine, mostly shallow.

3

How are cnidarians organized?

tissue-level: diploblastic with an endoderm and exoderm.

4

What is mesoglea?

non-cellular, jelly-like protein.

5

What is a cnidarian body plan?

radial symmetry, single mouth, no head, no anus.

6

What is cnidarian diversity?

>9000 species, fossils from >580 mya.

7

What is the cnidarian digestive system?

single digestive opening with cells that secrete digestive enzymes.

8

Do cnidarians have a nervous system?

no, but they have a nerve net that helps coordinate swimming.

9

True or false: cnidarians do not have a circulatory system.

True.

10

How do cnidarians exchange gases?

diffusion.

11

What is the only organ in cnidarians?

gonads.

12

What are cnidocytes?

cells that contain a stinging organelle called a nematocyst.

13

How do cnidarians eat?

prey on organisms using nematocysts, absorb organic chemicals, filter-feed, and symbiotic algae.

14

How do cnidarians reproduce?

medusa stage and polyp sage, both an asexual and sexual phase of life, hydrozoan cycle is from polyp to medusa.

15

Hydrozoa

water animal, polyp and medusa stage.

16

Polyp

looks like a plant, attaches to hard objects, buds asexually.

17

Siphonophores

colonial hydrozoan, string together in large groups, can emit light, dangerous to humans.

18

Scyphozoa

true jellyfish, medusa and polyp phases, large oral tentacles.

19

Cubozoa

no oral tentacles, medusa w/ broad paddles, squarish, some species with potent nematocyst toxin, boxy jellies.

20

Anthozoa

polyp stage only, radial symmetry, benthic, all marine, sea anemones and corals.