Lab 3 Flashcards
______ and ______ are supporting structures/fibres in sponges
Spicules Spongin
What are these? What are they made of? What cells produce them?
Sponge spicules. Made of calcium carbonate or silica, come from sclerocyte cells
What is spongin? What cells produce this?
Collagenous protein fibres that support the skeleton of sponges. Produced by spongocytes
_____ are the narrow openings in for water inflow in sponges
Ostia
______ are the larger openings for water outflow in sponges
Oscula
Most sponge species are of _____ construction
Leuconoid
Describe water circulation in asconoid sponges. Where are the choanocytes located?
In through small ostia (chambers through porocytes) and out through a large oscula at the top or the sponge. Choanocytes line the spongocoel
What are the three sponge body plans (list in order of increasing complexity)? Briefly describe how they fundamentally differ
Asconoid, syconoid, leuconoid. Basically they just have increasing degrees of invagination of the choanocyte layer away from the spongocoel
The inner body cavity of the sponge is known as the _____
Spongocoel
List the phylum, class, and genus of this organism. What type of sponge is it? Describe water circulation in this type of sponge. Where are the choanocytes located?
Phylum - Porifera
Class - Calcarea
Genus - Sycon
Syconoid sponge! Water enters through small Ostia (chambers) into bulbous pockets lined with choanocytes. Water leaves through a large hole in the top of the sponge called the syconoid
Describe water circulation in leuconoid sponges. Where are the choanocytes located?
Water enters through small Ostia and flows through many paths in the sponge, hitting chambers lined with choanocytes (water may pass many chambers) before flowing out of one of a few oscula at the top of the sponge
Why must asconoid sponges be small?
Because the body cavity is lined with a single layer of choanocytes, and large asconoid sponges would not be able to filter fast enough to support themselves
What are the advantages leuconoid sponges have over syconoid sponges?
Water may pass several choanocyte chambers before being expelled - higher chance for filtration
Why are choanocytes essential for the life of sponges?
They are the only cells specialized for feeding in sponges, so without them they would not be able to sustain themselves
Briefly describe class Calcarea of the sponges
Contains the only living asconoids, bear calcium carbonate spicules, very small, contain members of all three sponge types
List the phylum, class, and genus of this sponge (seen through dissecting scope). What is the body plan of this sponge? Where are the choanocytes located?
Phylum - Porifera
Class - Calcarea
Genus - Leucosolenia
Asconoid. Located in the body cavity (spongocoel)
Briefly describe class Demospongiae
Contains at least 90% of living sponge species, skeleton composed of spongin and/or siliceous spicules, all leuconoid
Name the phylum, class, and genus of this organism.
What type of sponge is this? What is the composition of it’s skeleton? Where are the choanocytes located?
Phylum - Porifera
Class - Demospongiae
Genus - Spongia
Leuconoid sponge.
Madeof Siliceous spicules and spongin
Choanocytes located in the choanocyte chambers
What is this and why are they so important for freshwater sponges?
GEMMULE!
Freshwater environments are vulnerable to drying out, freezing, losing oxygen, extreme nutrient variation. Gemmules, dormant structures produced by sponges, are resistant to dessication, anoxia, and freezing. They are the only reason freshwater sponges can survive
Briefly describe Class Hexactinellida
Skeleton composed entirely of siliceous spicules. Leuconoid or syconoid. Usually cylindrical or funnel shaped.
In this cross section of a sponge, what is located at “A”?
BABIES!!!!!!!!!!!!!!!!!!! (amphiblastula larvae)
Briefly describe phylum Cnidaria
Most are marine. All are radially symmetrical. Mouth is surrounded by tentacles leading to gastrovascular cavity. Body consists of two cell layers (epidermis and gastrodermis), all possess Cnidae (ex. Nematocysts), include polyp and medusa forms
Name the phylum and class of this organism. Briefly describe this class.
Phylum - Cnidaria
Class - Scyphozoa
Usually medusa body form, mesoglea thick and gelatinous (hence, jellyfish)
What is the mesoglea of Cnidarians
Middle cell layer, not a true cell layer
What is a manubrium?
Sort of like the pharynx equivalent, seen in Cnidarians. It conveys food to the stomach
Where is the mouth located in Aurelia medusa?
On the underside of the medusa (the concave side)
List the phylum, class, and genus of this organism. Describe the purpose of the circular structures in the middle.
Phylum - Cnidaria
Class - Scyphozoa
Genus- Aurelia
Gastric pouches are the site of digestion in Cnidarians. They contain nematocysts bearing tentacles called gastric filaments, which secrete digestive enzymes
What is the structure on Aurelia indicated by the pointer? What is it’s function?
Rhopalium. Stratocysts and ocelli are contained within these
What is the function of the organs within the rhopalia?
Balance (stratocysts) and light reception (ocelli). They sometimes also contain touch receptors
What stage in Aurelia’s life cycle is this? Does it result from sexual or asexual reproduction?
Planulus larva.
From sexual reproduction between two adult medusas.
What stage in Aurelia’s life cycle is this? What body form does it exhibit?
Scyphistoma. Is a sessile polyp used for asexual reproduction
What stage in Aurelia’s lifecycle is demonstrated on this slide? What is occurring and how?
Strobila stage.
Strobilation is occuring. The body column of a scyphistoma (polyp stage) subdivides upward. They eventually break away to form swimming ephyra, which become medusas
What stage in Aurelia’s life cycle is this? What is the purpose of this stage? Why are so many produced?
Ephyra stage.
Purpose is to develop into adults and reproduce sexually. Many are produced to ensure genetic success
List the phylum, class, and genus of this organism. Does it have a central mouth? What organisms give it a greenish colour?
Phylum - Cnidaria
Class - Scyphozoa
Genus - Cassiopea
No, they have many small mouths opening into a complex canal system.
They turn green by Harvesting zooxanthellae
Briefly describe class Hydrozoa
Have polyps and medusas, lack mesoglea
Name the phylum, class, and genus of this organism. Is it solitary or colonial? What type of symmetry does it have? Where are nematocysts found? How does the body move? What makes this organism’s life cycle unique?
Phylum - Cnidaria
Class - Hydrozoa
Genus - Hydra
They are solitary, bilaterally symmetrical, nematocysts in epidermis of tentacles. Body and tentacles move independently and tentacles draw food into mouth.
It has only a polyp stage (no medusa) in the life cycle
Name the phylum, class, and genus of this organism. Does this organism have a velum?
Phylum - Cnidaria
Class - Hydrozoa
Genus - Gonionemus
YES!
How does the velum aid in swimming in hydrozoans?
Causes water to be ejected from under the swimming bell through a narrower opening than those without velum.
Would you expect to find a velum in Aurelius medusa?
No, scyphozoans don’t have medusa
Name the phylum, class, and genus of this colony. Is this colony thecate or athecate? Do all members have the same function? Is the gastrovascular cavity continuous throughout the colony?
Phylum - Cnidaria
Class - Hydrozoa
Genus - Obelia
Thecate. Have different functions such as digestion or reproduction. Gastrovascular cavity extends interrupted through the body
What primary advantage does an *Obelia *colony have over *Hydra *spp.
They can reproduce sexually
What is the phylum, class, and genus. Describe this organism
Phylum - Cnidaria
Class - Hydrozoa
Genus - Physalia
Marine colonial hydrozoan that is commonly known as the Portugese man-o-war. Free floating and can REALLY hurt people
Briefly describe class Anthozoa
The largest class of Cnidarians, all marine. Have no medusa stage, and mesoglea containing amoeboid cells that are considered true connective tissue.
Name the phylum, class, and genus of this organism. Name and describe the funcion of the labelled parts
Phylum - Cnidaria
Class - Anthozoa
Genus - Metridium
A - Mesentery. These infoldings Increase surface area for digestive enzyme secretion and nutrient absorption
B - Acontia. Covered in nematocysts and secretory cells, can be extended outside the body. Used for offence, defence, and digestion
What layers of the body wall form the anthozoan mesenteries? What is the difference between complete and incomplete mesenteries? Which ofthese mesenteries has nematocysts?
Gastroderm and mesoglea.
Complete mesenteries - attach to pharynx
Incomplete mesenteries - extend partway into gastrovascular cavity. Covered in nematocysts and phagocytizing cells
Name the phylum, class, and genus of this organism
Phylum - Cnidaria
Class - Anthozoa
Genus - Madrepora
Name the phylum, class, and genus of this organism
Phylum - Cnidaria
Class - Anthozoa
Genus - Tubipora
