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13 Cards in this Set
- Front
- Back
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what are the different cells in the porifera
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choanocytes - pull in water, trap food, gamete production
archaeocytes - sponge version of stem cells. can change into necessary cells. used for food digestion and assimilation as well as gamete production amoebocytes - produce spicules pinacocyte -epidermal layer made up of spicules. helps regulate water flow |
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what are the three levels of structural complexity in the phylum porifera?
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- Asconoid (simplest structure. ostium lead straight into atruim and out osculum)
-sycnoid (ostium arranged in slightly more complex network, called radial canals) before entering the atrium and out through osculum) -Leuconoid (ostium create very complex networks called incurrent canals. lead to flagellated chambers where feeding occurs, exits through the excurrent canals and out via the osculum) |
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what are the characteristics of the phylum porifera
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-simplest multi-cellular animal (metazoa)
-cell rather than tissue differentiation -mostly asymmetrical -sexual and asexual reproduction -highly regenerative -all aquatic |
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Porifera - what is their general structure
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choanocytes ( feeding cells), osculum (top opening), atrium (centre chamber), ostia (poors for water/material entry)
cells are all arranged in gelatinous matrix (mesoglea) |
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Porifera - lifestyle and feeding
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- all aquatic, FW and marine
- choanocytes draw in water through ostia using their beating flagella, food particles stick to the colar microvilli, get pulled into head of choanocyte, taken to archaeocytes for digestion and assimilation |
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Porifera - body support and locomotion
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-skeleton is made up of spicules (silica or calcium compounds) and is secreted by amoebocytes
collagen fibres(spongin) gives structure - larvae moves via flagella. adults are sessile |
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Porifera - what functions are the flow of current important for?
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-respiration, feeding, circulation, excretion, osmoregulation and reproduction
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Porifera - what are the four classes and their characteristics (based on spicule type)
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-demospongiae (silica and spongin fibres)
-hexactinellida (silica, 6 rayed) - calcarea (CaCo, 1,3 or 4 rays) -sclerospongiae (silica & spongin fibres. ext. skeleton of CaCo) |
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Porifera - what are the types of spicules
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-siliceous spicules (hexactinellida. pointy, six rayed)
-siliceous spicules (demospongiae, 4 rayed mostly) -spongin (all interlocked, looks like sponge) -calcerous spicules (1,3 or 4 rays) |
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what is an animal
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-multi cellular, heterotrophic, develops from an embryo, cell and tissue differentiation, generally motile
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Porifera - reproduction
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- asexual via budding, fragmentation and gemules
- sexual reproduction. monoescious |
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what is a gemule and what produces these
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they are resistant capsules which are produced during asexual reproduction of spnges. fresh water only. very resilient
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Porifera - describe sexual reproduction
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-gametes arise from choanocytes or archaeocytes
-produce gametes (egg & sperm) at different times -sperm enters another sponge for fertilisation which occurs within the mesoglea - after fertilisation, larvae leave adult sponge, find suitable substrate and grow |
