Sponges and Cnidarians

Question 1

Phylum Porifera have body organization that is based on a system of

Answer 1

Water canal and chambers

Question 2

General characteristics of Porifera

• movement
• organs
• body wall

Answer 2

• adults are sessile and predominantly marine
• NO ORGANS, have pores on body instead for water currents to pass
• body wall contains a skeleton consisting of spicules and or spongin

Question 3

Differences of water circulation for each level of sponge construction

Answer 3

1. Asconoid: Thin choanocyte layer with large spongocoel, singular osculum
2. Synconoid: thicker and smaller spongocoel, body wall folding with invaginations (incurrent canals) and evaginations (radial canals), choanocytes in chambers not atrium, singular osculum
3. Leuconoid: Thickest choanocyte layer and no spongocoel, flagellated chambers, openings are prosopyles, many oscula

Question 4

Why are asconoid sponges smaller in height

Answer 4

-thin tissues is more breakable and can’t not support larger structures

Question 5

What are the advantages that the leuconoid sponges have over the syconoid sponges

Answer 5

Body plan provided more circulation to deliver more oxygen and nutrients per area. Body plan allows larger size

Question 6

Why are the choanocytes essential to the life of the sponge

Answer 6

Use to capture food, sleek and generate current of seawater through and within organism

Question 7

What is the function of the skeleton in a sponge

Answer 7

Maintains shape, scares predators and taxonomic tool to identify

Question 8

What is spongin

Answer 8

Modified collagen protein that is horny or fibrous and found in skeleton of many sponges

Question 9

Composition of spicules

Answer 9

Calcareous or siliceous (sclerocytes secrete spicules)

Question 10

Class-Calcarea characteristics

• size
• sponge types

Answer 10

• small usually less than 10cm
• lack spongin but have spicules of calcium carbonate
• include sponges of asconoid, syconoid and leuconoid design

Question 11

Leucosolenia sp.

• habitat
• sponge type
• where are choanocytes located

Answer 11

• Attached to seashore rocks
• asconoid
• in spongeocoel

Question 12

Sycon sp.

• type of sponge
• what are two types of chambers
• where are choanocytes
• larvae type in body walls???

Answer 12

• syconoid
• incurrent and radial canals
• choanocytes in chambers, not atrium
• small, dark dots in chambers called amphiblastula

Question 13

Class-Demospongiae contains what percent of all sponges?

Answer 13

90%

Question 14

Characteristics of class-Demospongiae

• skeleton
• sponge type

Answer 14

• Skeleton composed of spongin and or silica spicules

- all are leuconoid

Question 15

Spongia sp. (commercial bath sponge)

• composition of skeleton
• where are choanocytes
• type of sponge

Answer 15

• spongin
• entirely in chambers
• leuconoid

Question 16

Spongilla sp.

• type of sponge
• gemmules?

Answer 16

• leuconoid, demospongiae

- avoid harsh environmental conditions and a means of sexual reproduction

Question 17

Cliona sp.

• type of sponge
• what is it the “boring” sponge

Answer 17

• leuconoid

- ability to burrow into calcareous structures like clam shells

Question 18

Class-Hexactinellida characteristics

• known as
• skeleton composition
• sponge type

Answer 18

• glass sponges
• siliceous spicules
• cylindrical or funnel shaped and are syconoid or leuconoid

Question 19

Phylum Cnidarians include which species

Answer 19

• corals
• sea anemones
• jellyfish

Question 20

General characteristics of Cnidaria

• symmetry
• body
• body wall
• body forms

Answer 20

• radial symmetry
• no head or segmentation
• mouth surrounded by tentacles and connects to a gastrovascular cavity
• two layer body wall: epidermis and gastrodermjs with mesoglea in between
• have Cnidae of which nematocysts are most common
• polyp and Medusa forms (polymorphism)

Question 21

Subphylum-Medusozoa

2 classes of Meduosoza

Answer 21

All cnidarians except sea anemones and corals

Scyphozoa-true jellyfish
Hydrozoa

Question 22

Characteristics of class Scyphozoa

Answer 22

• Medusa is dominate body form

- mesoglea is very thick and gelatinous and contains Amoeboid cells

Question 23

Aurelia sp.

• what is manubrium
• purpose of gastric pouches

Answer 23

• meduosozoa, schphozoa
• opening of the mouth
• radial divisions of the stomach that help increase surface area

Question 24

Where are rhopalia on Aurelia sp. and what is the function

Answer 24

-around swimming bell, contain sensory organs for balance (statocysts) and light (ocelli)

Question 25

Aurelia sp. life cycle - does planula larva result from asexual or sexual reproduction - which body form does the scyphistoma exhibit - how does strobilation occur - purpose of free-swimming ephyra stage - advantage of large numbers of ephyra

Answer 25

- sexual reproduction - polyp - asexual reproduction by transverse division of the body into segments (ephyra) which develop into separate individuals - ephyra develop into adults but can also have adults differentiated into ephyra in unfavourable conditions - large number of adults can be made and larger chance of survival

Question 26

Cassiopea sp. - type - central mouth? - why green colour?

Answer 26

- scyphozoan - no central mouth but has many small oral openings leading into a complex canal system - endosymbiotic relationship with unicellular green algae (zooxanthellae) living inside the jellyfish

Question 27

Class-Hydrozoa characteristics - body form - mesoglea

Answer 27

- both polyp and Medusa forms present | - mesoglea lacks cells

Question 28

Hydra sp. - type - solitary or colonial - symmetry type - in which layer are nematocysts

Answer 28

- hydrozoan - solitary - radial symmetry - in epidermis

Question 29

Hydra sp. - are the bodies of Hydra capable of contraction? - do the movements of the body and tentacles appear coordinated - does it have a Medusa stage

Answer 29

- yes, can contract into a blob if disturbed - coordinated - NO MEDUSA STAGE

Question 30

Gonionemus sp. - type - does Medusa have a velum, what does it do if it does

Answer 30

- hydrozoan - yes, presence of velum causes water to be ejected from under the swimming bell through a narrower opening and thus greater velocity when the musculature contracts

Question 31

Do scyphozoans have velum?

Answer 31

No

Question 32

Obelia sp. - type - thecate or athecate colony? - do memebes of colony have same function - is the gastrovascular cavity continuous throughout colony - what are the advantages that Obelia has over hydra

Answer 32

- hydrozoan - thecate (have hydro theca around gastrozooid) - Gastrozoids=feeding, Gonozoids=contain developing Medusa - yes the light colony uninterrupted - 2 polyp stages (gastrozoid and gonozoid) which is more specialized than hydra. Has Medusa and polyp and divisor of labour

Question 33

Physalia sp. - type - commonly known as - colony?

Answer 33

Hydrozoan Portuguese man-of-war Free floating colony consists of nightly specialized polyploid and medusoid members

Question 34

Subphylum Anthozoa characteristics - body form - mesoglea

Answer 34

- polyp only | - mesoglea contains Amoeboid cells and is considered to be a true connective tissue

Question 35

Anthozoa’s comprise the ______ set of cnidarian classes and are exclusively _____ Examples

Answer 35

Largest Marine Sea anemones and corals

Question 36

Metridium sp. - type - why are mesenteries important - function of acontia

Answer 36

Anthozoa (sea anemone) - increase surface are in gastrovascular cavity for absorption of nutrients and gas exchange - located in gastrovascular cavity, are thread-like tissues containing numerous stinging cells which serve as a defence

Question 37

Metridium sp. - which layers of the body wall form mesenteries - what is the difference between complete and incomplete mesenteries? - what are advantages that Metridium has over Hydra

Answer 37

- gastrovascular cavity (unfolding of gastroderm and mesoglea) - primary/complete mesenteries extend from the body wall into the gastrovascular cavity to attach to the pharynx while incomplete mesenteries extend only part way into gastrovascular cavity. Free edge of incomplete mesenteries has nematocyst cells to secrete digestive enzymes and phagocytize bacteria - more surface area for nutrient, acontia

Question 38

Features of poriferans

Answer 38

- body is rigid, perforated bag, with flagella lining interior - body divided into: 1. Spongocoel (internal space) 2. Choanocyte (used to capture food and sleek and generate current) 3. Mesohyl (gelatinous, non living layer containing live and mobile Amoeboid cells called archaeocytes) 4. Epidermis (pinacocyte and nucleus)

Question 39

4 types of poriferans based on chemical composition of support elements

Answer 39

- calcarea - desmospongiae - Hexactinellida - Homoscleromorpha

Question 40

Where are gemmules found in sponges

Answer 40

Round structures scattered within the body of the sponge

Question 41

Medusa body form

Answer 41

(Jellyfish) - have umbrella shaped inverted mouth (facing downward) - often thick jelly-like layer in body wall as in jellyfish - motile by contractions of “bell” - free-floating, pelagic planktonic

Question 42

Polyp body form

Answer 42

-tubular body, usually sessile/ attached, mouth surrounded by tentacles