Invertebrate Practical 1

Grade of Construction of Sponges

Asconoid, Syconoid, Leuconoid

Ascinoid

The body wall is not folded to form chambers

Syconoid

Single osculum with folding of the body wall to allow for a greater number of choanocytes

Leuconoid

There is extensive folding of the interior body wall’ multiple ostia and oscula may be present

Porifera taxonomy

Class Calcarea, Class Demospongiae, Class Hexactinellida, Class Homoscleromorpha

Class Calcarea

shallow water, marine sponges; all three body plans represented with calcium carbonate spicules, 3-4 rayed spicules

Class Demospongiae

freshwater and marine sponges comprise over 95% of all known sponge species; network of siliceous spicules held together by a network of a collagen-like protein called spongin; all demonstrate leuconoid grade of construction

Class Hexactinellida

These marine sponger occur in deep water and are normally quite large; their body plans are similar to the syconoid grade of construction, though much of the body consists of a syncytium; spicules are six sided and made of silicon

Class Homoscleromorpha

sister group to class calcarea; exclusively marine sponges, most of which inhabt shallow hard bottom; small and encrust on surfaces

Grantia

Grantia whole mount slide

1. osculum
2. choanocyte chamber (flagellum face in)

Grantia whole mount slide labeled

Grantia spicules

Grantia grade of construction

syconoid

Spongia graminea

If spicules fizz when in contact with hydrochloric acid, they are composed of

calcium carbonate

Monaxon spicules

Triaxons

Triaxons

What is the best morphology a sponge could assume to maximize the photosynthetic potential of its symbionts?

Complex morphology because it create greater surface area as well desirable shelter for symbionts through increases crevices and branching.

Since sponges need to compete for hard substrate to attach to, what are other strategies to maximize photosynthetic potential?

Branching and growing upward and tall

Why would simple structures not work for large sponges?

They need more complexity to generate more time for filtration to obtain food as filter feeders

Best indicator of sponges environment

Shape due to adaptation to flow condition and predation

Relationship between number of spicules and environment of sponges

High energy sites require more spicules to increase the rigidity and toughness of the sponge in the high energy environment, whereas high spicule numbers are unnecessary in low energy environment

Relationship between shape of spicules and texture of sponge

More complex spicules resulted in harder sponges

Sponge Gemmule

Sponge gemmules

Gemmules

seed like capsules formed by sponges containing cells from which a new sponge can grow

Are gemmules produced sexually or asexually

asexually

Reason for sponges to include durable phase (gemmule) in its lifecycle

Changes to environment can result in extreme conditions that incentivize sponges to have a durable phase to ensure reproduction

What are the layer of hexactinellida made of

syncytial

Syncytial

multiple nuclei are contained within a single plasma membrane

Hexactinellida

Commensal relationship for class hexactinellida

Male and female commensal shrimpy enter the glass sponge when small and live inside together for their life

Hexactinellida spicule

Cnidarian Taxonomy

Subphylum Medusozoa (Class Hydrozoa, Class Scyphozoa, Class Cubozoa, Class Staurozoa), Subphylum Anthozoa (Class Anthozoa)

Class Hydrozoa Taxonomy

Order Thecata, Order Athecata (Suborder Aplantulata, Suborder Capitata), Order Siphonophora

Class Cubozoa Taxonomy

Order Cubomedusae

Class Anthozoa Taxonomy

Subclass Octocorallia (Order Alcyonacea (form. Order Gorgonacea), Order Pennatulacea), Subclass Hexacorallia (Order Actiniaria, Order Scleractinia)

sea fan

sea whip

Taxonomy of Sea Fans/Sea Whips

Subphylum Anthozoa, Class Anthozoa, Subclass Octocorallia, Order Gorgonacea

Sea fan orientation in the water

perpendicular to allows feeding of polyps on downstream end

Sea Pansy (Renilla vermiformis)

Taxonomy of sea pansy

Subphylum Anthozoa, Class Anthozoa, Subclass Octocorallia, Order Pennatulacea

Gastrozooid (feeding) and Siphonozoid (Water intake)

Polyps on sea pansy

What does the addition of spicules in the hydrostatic skeleton of the sea pansy do to the mechanical function of tissue?

The addition of spicules makes it more rigid

General structure of stony corals

Polyps sit in the grooves/holes

Metridium senile

Metridium senile taxonomy

Subphylum Anthozoa, Class Anthozoa, Subclass Hexacorallia, Order Actiniaria

Representatives of Order Scleractinia

Fire Coral (Millepora)

Fire Coral Taxonomy

Subphylum Medusozoa, Class Hydrozoa, Order Athecata, Suborder Capitata

Northern Star Coral (Astrangia poculata)

Northern Star Coral (Astrangia poculata)

Which organism exhibits facultative symbiosis?

Astrangia poculata

Facultative symbiosis

Can live with very few symbionts

Polyps of astrangia poculata

Astrangia poculata taxonomy

Subphylum Anthozoa, Class Anthozoa, Subclass Hexacorallia, Order Scleractinia

Why might an organism exhibit facultative symbiosis/have very different morphological states?

So that it is able to exist in harsh conditions in which there is unstable number of symbionts. It remains hardy.

Portuguese man of war (Physalia physalis)

By-the-wind-sailor (Velella velella)

Little blue button (Porpita porpita)

Ostrich Plume hydroid (Aglaophenia rigidida)

Siphonophore pneumatophore

1. pneumatophore
2. gonozooids
3. gastrozooids
4. dactylozooids

Taxonomy of siphonophores

Subphylum Medusozoa, Class Hydrozoa, Order Siphonophora

Taxonomy of Obelia

Subphylum Medusozoa, Class Hydrozoa, Order Thecata

Obelia hydroid colony

1. gastrozooids
2. gonozooids

Taxonomy of Aurelia aurita

Subphylum Medusozoa, Class Scyphozoa

Aurelia aurita

How do scyphozoa use the mesoglea for locomotion?

Water contained between the bell and the mesoglea is expelled by muscle contraction and the jellyfish is propelled

Why is the mesoglea springy?

It is muscular and required for locomotion and needs to be able produce force

What opposes the action of the muscles that contract the bell during the powerstroke of swimming?

The pressure of water filling the shape of the bell forces it to return back to its shape

Does the mesoglea in the bell of a medusa constitute a hydrostatic skeleton?

The mesoglea functions as a hydrostatic skeleton

1. epidermis
2. mesoglea
3. gastrodermis
4. stomach
5. mouth
6. oral-aboral axis
7. manubrium
8. gonad
9. tentacle
10. subgenital pit
11. oral arm

1. oral arms
2. perradial brachial grooves
3. mouth
4. marginal tentacles
5. rhopalium
6. gastric pouches
7. oral arms
8. ring canal

Where are the cnidocytes on Auralia

on the marginal tentacles

1. sensory lappet
2. ocellus
3. protective hood
4. statocyst
5. rhopalium lappet

function of rhopalium

maintain equilibrium and permit photo reception

Why do scyphomedusae have a more complex system of gastric canals than hydromedusae?

They are larger and thus need a more complex system to distribute nutrients

nematocyst

Aurelia ephyra

Aurelia scyphistoma

Aurelia scyphistoma

Aurelia planula larva

Gonionemus medusa

1. Manubrium
2. Radial canals
3. Gonads
4. Tentacles

Taxonomy of Gonionemus medusa

Subphylum Medusa, Class Hydrozoa

Why are the medusae of hydrozoans so much smaller than the medusae of scyphozoans

They have simpler body structure and thus need to be smaller

Phylum Ctenophora taxonomy

Class Tentaculata and Class Nuda

Order of Mnemiopsis

Order Lobata

Mnemiopsis macrydi

1. Anal pores
2. Statocyst
3. Opening of tentacle sheath
4. Gastrovascular cavity
5. Mouth
6. Pharynx
7. Base of tentacle sheath
8. Comb
9. Tentacle
10. Tentacular plane
11. Pharyngeal plane
12. Ciliary comb

Locomotion of ctenophores

ciliary and muscular (for orientation and rapid escape)

Why do ctenophores use muscular movement to escape from predators?

it is more precise, allows them to flatten and contract

How could jellyfish use sensory information from ocelli to alter its visibility

Use ocelli to detect light sources and contract and flatten to create minimal visibility

Taxonomy of Phylum Platyhelminthes

Order Polycladida, Order Tricladida, Cohort Monogenea, Cohort Trematoda, Cohort Cestoda

Taxonomy of Phylum Xenacoelomorpha

Subphylum Acoelomorpha, Class Acoela