Phylum Cnidaria (Coelenterata)

Question 1

Habitat?

Answer 1

Aquatic (mostly marine)

Question 2

Symmetry

Answer 2

Radial

Question 3

Multiple life stages? If so, what kind?

Answer 3

Yes, 2 major life stages

• Polyp
• Medusa

Question 4

Gut?

Answer 4

Blind gut, gastrovascular cavity

Question 5

Nematocysts

Answer 5

Specialized cells for prey capture (and defense)

• Distinctive of Cnidaria
• some inject toxins

Question 6

Parts of nematocyst

Answer 6

• Filament, barb, cnidocyte, cnidocil

Question 7

What is a Cnidocyte

Answer 7

Specialized cell housing nematocyst

- Abundant on tentacles

Question 8

What are the barbs and filament of a nematocyst used for?

Answer 8

Piercing and entangling prey

Question 9

What triggers nematocysts?

Answer 9

physical and chemical stimuli

Question 10

What is the Mesoglea?

Answer 10

Middle layer of cells, jelly material

Question 11

What does the endoderm do?

Answer 11

Takes up nutrients

Question 12

What is the major function of tentacles

Answer 12

Capture and transport prey to mouth

• Can grow new ones
• Retractable

Question 13

Gastrovascular cavity

Answer 13

Where initial digestion occurs, with enzymes

- digestion completed intracellularly

Question 14

Symbiotic relationships?

Answer 14

Algae cells that grow in endoderm or mesoglea

Question 15

Nervous system?

Answer 15

Nerve net and muscular system

Question 16

Reproduction method

Answer 16

Sexual and Asexual

Question 17

Larva?

Answer 17

Planula, develop from gametes

Question 18

What are 2 major distinguishing characteristics of Cnidaria?

Answer 18

Life stages (polyp and medusa)
and
Nematocysts

Question 19

Coelom?

Answer 19

Acoelomate

Question 20

What are the 2 life stages of Cnidaria?

Answer 20

Polyp and Medusa

Question 21

5 Facts about Polyps

Answer 21

• Sessile
• Aboral and oral ends
• Feeding tentacles
• Singular or colonial
• Polymorphic (feeding, defense, or reproductive polyps)

Question 22

3 Facts about Medusa

Answer 22

• Free swimming
• Bell shaped
• Tentacles around mouth
  (- lifespan usually annual)

Question 23

Locomotion

Answer 23

Medusa swim by jet propulsion

- Polyps have limited movement if any

Question 24

Reproduction

Answer 24

• release of gametes into water column

- Embryo develops into planktonic planula larva

Question 25

Where is Class Hydrozoa found?

Answer 25

Marine, some freshwater

Question 26

Life stages of Class Hydrozoa?

Answer 26

Both polyp and medusa

Question 27

Describe the polyps of Class Hydrozoa and how their life cycle operates

Answer 27

Planula larva settles to produce Polyps

• Polyps are asexual that bud and form colonies (Obelia has colonies)
• Entire colony is from one planula larva formed from asexual budding.

Question 28

Where is class Scyphozoa found?

Answer 28

All Marine, most open ocean

Question 29

Describe life cycle of Class Scyphozoa

Answer 29

• Zygote develops on oral arms of female medusa and forms planula
• Planula larva settles to form scyphistoma
• Scyphistoma replicate by budding
• Scyphistoma transform into strobila polyp (strobilating scyphistoma)
• Strobila produce ephyra
• Ephyra develop into medusa

Question 30

What is an Ephyra

Answer 30

Juvenile Scyphozoa medusa

Question 31

5 Facts about Class Cubozoa (non local)

Answer 31

• Previously part of Scyphozoa
• Medusa predominant
• Box shaped (Box Jellies)
• Capture fish
• Potent Nematocysts

Question 32

4 Facts about Class Anthozoa

Answer 32

• Anemones, corals, and sea pens
• No medusa stage
• All marine
• Solitary or colonial (corals)

Question 33

Which Class has the velum?

Answer 33

Hydrozoa