Zoology Test 2-Sponges

Class Demospongiae

-comprise approximately 80% of all sponge species, including most larger ones -skeletons may be composed of siliceous spicules, sponging fibers, or both -all members of the class are leuconoid and all are marine except one family, the freshwater Spongillidae (well-oxygenated ponds and streams that encrust plant stems and old pieces of submerged wood) -marine demospongiae vary in color and shape

syconoid canal system

-derived from asconoids -tubular body and a single osculum that is folded back and forth to make canals -choanocytes line certain folds called radial canals -the spongocoel is lined with epithelial-type cells rather than with choanocytes like asconoids -are in the Calcarea FLAGELLATED CANALS

Class Homoscleromorpha

-marine sponges that occur in a range of colors, but live in cryptic habitats -common in nearshore habitats, but can occur in deep water -pinacoderm layer with a true basement membrane or ECM (true tissue) -adherens cell junctions join cells together in this layer -class divided into 2 clades: one whose members lack spicules entirely, and the other with spicules that do not form around a central longitudinal (axial) filament -have type IV collagen

leuconoid canal system

-most complex of the sponge type and permits an increase in sponge size -most form large masses with numerous oscula -NO SPONGOCOEL -most sponges are of this type which occurs in most Calcarea and in all other classes -has evolved independently many times in sponges -clear adaptive value that increases the proportion of flagellated surfaces compared with the volume, thus providing more collar cells to meet food demands -FLAGELLATED CHAMBERS

pinacocytes

-nearest approach to a true tissue in sponges is the arrangement of the ? cells of the external epithelium. -thin, flat, epithelial-type cells cover the external surface and some interior surfaces -somewhat contractile and help to regulate the surface area of the sponge -some are modified as contractile myocytes-arranged in circular bands around the oscula or pores, where they help to regulate the rate of water flow (similar microfilaments to muscle cells) -specialized for a particular function but not a true tissue epithelium because do not rest on a basal (basement) membrane or ECM, but tissue-like so called an "incipient tissue"

pinatocytes/archaeocytes

? may phagocytize particles at the surface, but most larger particles are consumed in the canals by ? that move close to the lining of the canals

myocytes/hexactinellida

Cell Communication • Some response to stimuli-propagation of coordination of dilation or closure of channels • Contraction by ? (amoebocytes) with arrays of cytoselektetal elements: Fibril • Coordination of poison release. Terpios—grow 23mm • ? stop flagella beating based on electrical stimulation- impulses travel along syncytium structure.

Mesohyl/choanocytes/pinacocytes/amoebocytes/porocytes/sclerocytes/spongocytes/collenocytes

Cytological Morphology Sponge Cell Types •?-supporting neighboring cells not bonded to a basement membrane • ?-collar cells (Choanoderm);generates water current • ?-comprise the outer layer (Pinacoderm) • ? (Archaeocytes)-wander through mesohyl • ?-make up ostia • ?- secrete spicules • ?- secrete spongin • ?- secrete fibirillar collagen

choanocytes/amoebocytes

Feeding • ? • ? assist in distributing nutrients through sponge. • Canal system complexity • Expulsion of water carries wastes some distance away.

ostia/oscula/spongocoel/spicules

Gross Morphology PORES. • ?-incurrent Current created by beating choanocytes • ?-outcurrent BODY. • ?-center • Skeleton - Spicules: Calcareous-calcite, Siliceous-silica - Spongin: collagen-like protein

flagellated/gastrulation

Larva details Larvae ? • Develop w/in parent • Asexual fragmentation dispersed followed by larvae released from fragments • Sexual larvae settle cellular rearrangement corresponding to ?

spicule morphology

Porifera Systematics • Life-form structure-- too variable • Chemotaxonomy—uncertain • ?—main characters • Syncytial nature of the choanoderm and pinacoderm • Morphological—DNA barcoding

gemmules/archaeocytes/mesohyl/monoecious/choanocytes/oocytes/choanocytes/ciliated larva/choanocytes

Reproduction 1. Asexual Reproduction a. External buds are small individuals that break off after attaining a certain size. b. Internal buds or ? are formed by ? that collect in ? and are coated with tough spongin and spicules; they survive drought, freezing, etc. 2. Sexual Reproduction a. Most are ? with both male and female sex cells in one individual. b. Sperm arise from transformed ? (gametogenesis-dedifferentiation of cells. c. In some Demospongiae and Calcarea, ? develop from ?; others derive them from archaeocytes. d. Sponges provide nourishment to the zygote until it is released as a ?. e. In some, when one sponge releases sperm, they enter the pores of another. f. ? phagocytize the sperm and transfer them to carrier cells that carry sperm through mesohyl to oocytes. g. Some release both sperm and oocytes into water.

amoebocytes/apostommatic/biotoxins/cliondae

Sponge Biochemistry • Color - ? with pigment granules. ? • Produce various bioactive compounds—? • ?—boring sponges specialized amoebocytes, dissolving calcareous matrix • Māoris use sponges as anti-inflammatory

somatic embryonogenesis

Sponges can regenerate wounded portions. Sponge fragments aggregate into new structures, this is ?.

totipotency/ differentiation reversible

Sponges have Cellular ? and are cellular ?

diffusion/contractile vacuoles

Sponges have no respiratory or excretory organs; these functions are performed by ?; ? occur in the archaeocytes and the choanocytes of freshwater sponges.

cell adhesion and cell signaling/a true epithelium some sponges/blastula stage and some have a two-layered gastrula stage

The proteins used in ? and ? in sponges are homologous to those in other metazoans; many of these occur in choanoflagellates/other 2 things that link sponges to metazoans

taxonomic importance

There are many variations in the shape of spicules and these structural variations are of

monoecious/choanocytes

all sponges can reproduce both sexually and asexually -in sexual reproduction, most sponges are ? (having both male and female sex cells in one individual). Sperm arises from transformation of ? that act as carrier cells and then carry the sperm thru the mesophyll to the oocytes

archaeocytes

ameboid cells that move thru the mesophyl and perform a number of functions -they can phagocytize particles at the external epithelium and receive particles for digestion from choanocytes -can differentiate into any of the other types of more specialized cells in the sponge -sclerocytes:secrete spicules, spongocytes:secrete the sponging fibers of the skeleton, collencytes:secrete fibrillar collagen

sponge body

an assemblage of cells embedded in an extracellular matrix and supported by a skeleton of minute, needlelike spicules (calcium carbonate or silica and collagen) and protein -bear myriads of tiny pores and canals that constitute a filter-feeding system adequate for their inactive lifestyle -sessile animals that use water currents carried thru their unique canal systems to bring them food and oxygen and to carry away their body wastes -disassociated cells can form a new sponge body -ancient group extending back to the early Cambrian period and even, some claim, into the Precambrian period -mostly marine, but some 150 species occupy fresh water

oviparous

besides being monoecious, other sponges are ?; ova are fertilized by motile sperm (without carrier cells) in the mesophyll. There the zygotes develop into flagellated larvae, which break loose and are carried away by water currents

Class Calcarea

calcareous sponges that have spicules composed of calcium carbonate (straight monaxons or have 3 or 4 rays) -sponges tend to be small, tubular or vase-shaped -can be asconoid, syconoid, or leuconoid in structure

collar bodies

choanoblasts are unusual cells that make 2 or more flagellated outgrowths. The flagellum on a ? beats to drive water flow in the same way that it would on a choanocyte -an assemblage of ? forms a flagellated chamber. Here the trabecular reticulum branches to become two distinct bilayered sheets: a primary reticulum and a thin secondary reticulum that lacks mesohyl. The two layers make a sandwich around the center of a collar body. To collect food, the incurrent water is directed to the primary reticulum, where pores enter the space btwn the primary and secondary reticular sheets. Water entering this space must leave by moving thru the mesh of microvilli on collar bodies (Class Hexactinellida)

intracellular/archaeocytes

digestion of sponges is entirely ? a chore performed by the ?

Calcarea, Demospongiae, Hexactinellida, homoscleromorpha

four classes of sponges: -having calcareous spicules -having a skeleton of siliceous spicules or sponging or both -having six-rayed siliceous spicules -thin encrusting sponges that have simple spicules or lack spicules entirely

parenchymula

free-swimming larva of most sponges are called ?

cladorhizids

inhabit nutrient poor deep-water caves -each sponge has a fine coating of fine coating of tiny, hooklike spicules over its highly branched body

trabecular reticulum

is bilayered and can be sheetlike or tubular -btwn the layers of the sheet, or inside the tubes, is a thin collagenous mesophyll in which cells, such as archaeocytes or choanoblasts, occur (Class Hexactinellida)

choanocytes

line flagellated canals and chambers -are ovoid cells which one end embedded in mesohyl and the other exposed -exposed end bears a flagellum surrounded by a collar which is composed of adjacent microvilli connected to each other by delicate microfibrils so the collar forms a fine filtering device for straining food particles from the water. The beat of a flagellum pulls water thru the sievelike collar and forces it out thru the open top of the collar

collagen/spongin/siliceous spicules/crystalline calcium carbonate/siliceous spicules with 6 rays

major structural protein in the animal kingdom and fibrils of this occur throughout the extracellular matrix of all sponges -Demospongiae secrete a form of this traditionally called...also secrete....and calcareous sponges secrete spicules composed mostly of......that have one, three, or four rays. Glass sponges (Hexactinellida) have....arranged in three planes at right angles to each other

Class Hexactinellida/syncytial/trabecular reticulum

nearly all deep-sea forms -most are radially symmetrical -skeleton of six-rayed siliceous spicules bound together in an exquisite glasslike latticework -body is ?-many nuclei inside a single very large cell. This single, continuous syncytial tissue is called a ?

Devonian period

saw rapid development of many glass sponges

asconoid canal system/spongocoel

simplest organization -small and tube-shaped -water enters through microscopic dermal pores into a large cavity called a ? which is lined with choanocytes and water is expelled through a single large osculum -all ? are in Calcarea FLAGELLATED SPONGOCOELS

mesohyl

sponge cells are loosely arranged in a gelatinous matrix called...which is the connective tissue of the sponges; in it are found various ameboid cells, fibrils, and skeletal elements. Includes: -pinacocytes -porocytes -choanocytes -archaeocytes

free-swimming/always attached

sponge embryos are....while adult embryos are...

particles/organic matter/phagocytosis

sponges feed primarily on particles suspended in water pumped thru their canal systems/consume a sig portion of their nutrients in the form or ? dissolved in water circulting thru the system. Such material is ingested by a process similar to ?

shape of the substratum, direction, speed of water currents, availability of space

sponges growth patterns depend on 4 things...

fragmentation and by forming external buds that detach or remain to form colonies/gemmules

sponges reproduce asexually by...and... -freshwater sponges and some marine sponges reproduce asexually by regularly forming internal buds called ? that form during unfavorable conditions; when favorable conditions return, archaeocytes in the gemmules escape and develop into new sponges.

asconoid, syconoid, and leuconoid

three types of canal systems

ostia

tiny pores for incoming water

porocytes

tubular cells that pierce the body wall of asconoid sponges, through which water flows

oscula (osculum)/choanocytes/dermal ostia

water outlets. This and Ostia are openings connected by a system of canals, some of which are lined with peculiar flagellated collar cells called....whose flagella maintain a current of environmental water through the canals. Water enters the canals through a multitude of tiny incurrent pores and leaved by way of one or more large oscula.

Calcarea

• CaCO3 spicules • all are marine Most are small sponges with tubular or vase shapes. Asconoid, syconoid and leuconoid forms all occur.

Desmosponges/zoochorellae/gemmules/mixotrophic

• Freshwater sponges (?) • Range from freshwater to brackish • Green from "?" • Diapuase (overwinter) • Reproduction: ? • freezing/thawing • 3 years dried • anoxia conditions • Nutrition ? with algal endosymbioants • Sponge associations • Caddisfly Ceraclea fluva • Spongiflies Feeding

Hexactinellida

• SiO3 spicules • 6-rayed spicules • all are marine • Lacks pinacocytes Nearly all are deep-sea forms; most are radially symmetrical.

Demospongiae

• SiO3 spicules • may have spongin • Marine / freshwater This class contains 95% of living sponge species. They may be absent or bound together by spongin. All are leuconoid and all are marine except for Spongillidae, the freshwater sponges.