Phylum Cnidaria

Question 1

Phylum Cnidaria

Answer 1

One steps above sponges

Question 2

Notable traits

Answer 2

Radial symmetry
Diploblastic (two germ layers)
Tissues, but no organs
Gastrovascular system
Cnidocytes
Mesoglea (jelly)
Nerve net

Question 3

Cnidocytes

Answer 3

Stinging cells

Question 4

Nematocysts

Answer 4

Coiled harpoon inside cnidocyte that produces neurotoxins (which are painful and potentially deadly)

Question 5

Diploblastic layers

Answer 5

Endoderm -> Gastrodermis
Ectoderm -> Epidermis
[Both must be in contact with water to function]

Question 6

Dimporphic body plan

Answer 6

Mesoglea (jelly layer)
Polyps (sessile) vs Medusa (mobile)

Colonial vs Solitary

Question 7

Colonial

Answer 7

Many buds attached to one another
Gastrozooid (feeding) and Gonozooid (reproduction)
Ex Coral

Question 8

Solitary

Answer 8

One organism
Ex Polyps and Medusae

Question 9

Life cycle

Answer 9

Can have both polyp and medusa stages
Monoecious vs dioecious

Question 10

Medusa

Answer 10

“True jellies”
Ex box jellies

Question 11

Polyp form

Answer 11

Ex Corals and sea anemones

Question 12

Incomplete digestive system

Answer 12

Gastrovascular cavity with one opening
Water is circulated through

Question 13

Four classes

Answer 13

Anthozoa
Scyphozoa
Cubozoa
Hydrozoa

Question 14

Anthozoa

Answer 14

“Flower animals”
Sea anemones & coral
[Gastrovascular cavity into septa]

Question 15

Scyphozoa

Answer 15

“Cup animals”
True jellies
Medusa lacks velum thus slower movement

Question 16

Cubozoa

Answer 16

“Box animals”
Box jellies (cube-shaped)
With pedalia and has the most deadly sting

Question 17

Hydrozoa

Answer 17

“Water animals” “Hydroids”
Medusa has velum

Siphonophores (protrudes from top of medusa to aid in movement)

Many are colonial organisms