BIO044 (LAB) MOD 8 CNIDARIA (JELLIES, HYDRAS, AND CORALS)

Question 1

Contains a large number of interesting animals, but most of the 10,000 or more
species live in salt water and are seen alive by only a small proportion.

Answer 1

Phylum Cnidaria

Question 2

The members of Phylum Cnidaria consist of.

Answer 2

radially symmetrical animals

Question 3

Phylum Cnidaria is

Answer 3

Dipoblastic

Question 4

Dipoblastics have 2 true tissue layers:

Answer 4

• Ectoderm
• Endoderm

Question 5

Ectoderm forms the outer layer:

Answer 5

Epidermis

Question 6

Primitive nervous system without a brain.

Answer 6

nerve net

Question 7

Contractile epithelial cells for movement; not true
muscles.

Answer 7

epitheliomuscular cell fibers

Question 8

Endoderm forms the inner layer.

Answer 8

gastrodermis

Question 9

The space in between the epidermis and gastrodermis is
filled with an extracellular matrix made of 96% water called the______.

Answer 9

mesoglea

Question 10

Cnidarians display?

Answer 10

dimorphism

Question 11

Cnidarians display dimorphism. They come in two (2) forms:

Answer 11

Polyp and Medusa

Question 12

Which is sessile and reproduces sexually.

Answer 12

Polyp

Question 13

Which is free-swimming and reproduce sexually.

Answer 13

Medusa

Question 14

(“outer skin”) the outer tissue layer.

Answer 14

Epidermis

Question 15

(“middle gel”) jelly-like middle layer which maintains the shape of the cnidarian. It is wider in medusas and narrower in polyps.

Answer 15

Mesoglea

Question 16

(“stomach skin”) the inner tissue layer that is lined with gastrodermal cells, which releases digestive enzymes when food enters the gastrovascular cavity

Answer 16

Gastrodermis

Question 17

The incomplete/blind gut. It is often branched and extending into the tentacles.

Answer 17

Gastrovascular cavity

Question 18

As the gut is incomplete, cnidarians only have one orifice for ingestion of food and excretion of waste.

Answer 18

Mouth/Anus (Oral disc)

Question 19

Extensions of the body that forms a ring around the oral disc.

Answer 19

Tentacles

Question 20

It is lined with
stinging cells called:

Answer 20

cnidocytes

Question 21

Which houses a stinging organelle to capture and deliver toxins to prey.

Answer 21

nematocysts

Question 22

Found only in the medusa form; it is the concave “top” of a jellyfish.

Answer 22

Bell

Question 23

Found only in the polyp form; it is the “stalk” of the polyp which attaches it to the
substrate/sea floor.

Answer 23

Pedal disc

Question 24

Fund only in corals (Class Anthozoa); secretes an exoskeleton made of calcium
carbonate.

Answer 24

Calicle

Question 25

Major Classes of Cnidarians:

Answer 25

• Class Hydrozoa (hydra)
• Class Scyphozoa (true jellyfishes)
• Class Cubozoa (box jellyfishes)
• Class Anthozoa (corals and anemones)

Question 26

Most with polyp and medusa stage, but polyp form is dominant.

Answer 26

Class Hydrozoa (hydras)

Question 27

Most with polyp and medusa stage, but medusa form is dominant.

Answer 27

Class Scyphozoa (true jellyfishes)

Question 28

Box like shape medusas with unknown polyps. Consists of the most poisonous jellyfishes.

Answer 28

Class Cubozoa (box jellyfishes)

Question 29

Polyp stage only; mostly colonial; calcium carbonate exoskeleton.

Answer 29

Class Anthozoa (corals and sea anemones)

Question 30

The cnidarian gastrodermis originated from?

Answer 30

Endoderm

Question 31

This is an extracellular matrix between the epidermis and gastrodermis that is made of 96% water:

Answer 31

Mesohyl

Question 32

These are cells that releases digestive enzymes.

Answer 32

Gastrodermal

Question 33

This cnidarian form is free-floating.

Answer 33

Medusa