3. Porifera Flashcards
Why are porifera animals? 7
- multicellular 2. heterotrophic, no photosynthesis 3. no cell walls 4. strongly dimorphic gametes 5. dna evidence suggests so 6. ecm including receptor tryrosine kinases and collagen integrin 7. 5-HT, neuropeptide Y
Why are porifera animals? 7
- multicellular 2. heterotrophic, no photosynthesis 3. no cell walls 4. strongly dimorphic gametes 5. dna evidence suggests so 6. ecm including receptor tryrosine kinases and collagen integrin 7. 5-HT, neuropeptide Y
Describe porifera phylogeny. 5
- Are metazoa, not eumatazoa (true animals) 2, branched very early 3. seems most likely that sponges are the earliest extant metazoa 4. true order unclear between porifera, placozoa and ctenophora 5. The phylogeny of ctenophores is more complicated, some think they diverged after bilateria, others think long before, others think at the same time
What is the significance of porifera research? 2
- there is shared biology between bilaterians and non-bilaterians 2. many are only interested in bilaterians but ignored the non-bilaterian keeps us ignorant of many aspects ofv ariability
What are the key traits of porifera? 6
- specialisation of cells, not organs and not usually tissue 2. simplest multicellular animals 3. up to 2 m tall 4. all have ostia (pores) that draw in water, oxygen and food 5. ostia are make of a skeleton of spicules, a glass like substance, and collagen 6. difficult to eat and few predators, therefore succssful
Describe porifera ecology. 6
- about 5000 species 2. mostly marine - ancestral form 3. about 150 species are freshwater, derived form 4. usually found in tropical areas 5. can make up to 75% of biomass in antarctic sea floor 6. other species live on sponges eg. some crustaceans
What role does porifera play in the ecosystem? 6
- filtering and neutralisation of pollutants (bioremediation) 2. contributes to biomass of intertidal zones 3. form habitats eg. coral reefs, soft sediment 4. contain metabolites that can be used in pharmaceuticals, incl anti-tumour and anti bacterials 5. important roles in nitrogen, carbon and silican cycles 6. provide habitats for increased diversity and invertebrate biomass
What role does porifera play in the ecosystem? 6
- filtering and neutralisation of pollutants (bioremediation) 2. contributes to biomass of intertidal zones 3. form habitats eg. coral reefs, soft sediment 4. contain metabolites that can be used in pharmaceuticals, incl anti-tumour and anti bacterials 5. important roles in nitrogen, carbon and silican cycles 6. provide habitats for increased diversity and invertebrate biomass
Describe porifera phylogeny. 5
- Are metazoa, not eumatazoa (true animals) 2, branched very early 3. seems most likely that sponges are the earliest extant metazoa 4. true order unclear between porifera, placozoa and ctenophora 5. The phylogeny of ctenophores is more complicated, some think they diverged after bilateria, others think long before, others think at the same time
What is the significance of porifera research? 2
- there is shared biology between bilaterians and non-bilaterians 2. many are only interested in bilaterians but ignored the non-bilaterian keeps us ignorant of many aspects ofv ariability
What are the key traits of porifera? 6
- specialisation of cells, not organs and not usually tissue 2. simplest multicellular animals 3. up to 2 m tall 4. all have ostia (pores) that draw in water, oxygen and food 5. ostia are make of a skeleton of spicules, a glass like substance, and collagen 6. difficult to eat and few predators, therefore succssful
Describe porifera ecology. 6
- about 5000 species 2. mostly marine - ancestral form 3. about 150 species are freshwater, derived form 4. usually found in tropical areas 5. can make up to 75% of biomass in antarctic sea floor 6. other species live on sponges eg. some crustaceans
describe the sponge holobiont. 4
What role does porifera play in the ecosystem? 6
- filtering and neutralisation of pollutants (bioremediation) 2. contributes to biomass of intertidal zones 3. form habitats eg. coral reefs, soft sediment 4. contain metabolites that can be used in pharmaceuticals, incl anti-tumour and anti bacterials 5. important roles in nitrogen, carbon and silican cycles 6. provide habitats for increased diversity and invertebrate biomass
What are archaeocyanths? 6
- May be an early form of sponge 2. fossils from lower (older) cambrian - 530m yr ago, DNA suggests they existed earlier but no fossil evidence 3. hundreds of species 4. contribute to reef formation 5. had many pores on body 6. disappeared within 15m years
What areasconoid sponges? 2
- water is drawn in through sides 2. ejected through osculum
What are syconoid sponges? 2
- water drawn in through radial canals 2. ejected through osculum
What are leuconoid sponges? 3
- complex internal canal structure 2. osculum 3. largest sponges are these
What should you remember about the -oid classifications of porifera? 3
- the groups are convergent - different branches have found the same solutions 2. they are morphological, not monophyletic 3. water may enter in sides of all three and come out of top
what does monophyletic mean? 1
- taxon containing ancestor and all descendants
Describe Demospongiae. 2
- 95% of sponges 2. have leuconoid canal systems
Describe calcarea. 5
- small 2. straight spicules 3. often vase shaped 4. less than 5% sponges 5. all three body plans
describe hexactinellida. 4
- glass sponges 2. deep sea 3. huge syncytial tissue 4. has a trabcular reticulum - complex spicule holding system
What is important to remember about the Porifera classes? 2
- the evolutionary relationships between them are unclear 2. previously suggested that sponges are paraphyletic but no longer widely accepted
what does paraphyletic mean?
ancestor and descendants, excluding 1+ monophyletic subgroups
What are choanocytes? 4
- independent cells, similar to chaonoflagellates that are found in sponges 2. collared with specialised flagella 3. Organic rot sticks to cell and is phagocytosed through collar for intracellular digestion 4. supports sponges being origin of multicellular life
What is a syanamorphy and what are the syanamorphies of sponges? 8
- Traits shared by one group and no others 2. chaonocytes 2. aquiferous system with external pores 3. mineral spicules 4. high cellular mobility and totipotency 5. body continuously remoulds itself 6. rearrangement by movement of cells inside sponge 7. changes from one differentiated form to another
Describe the reorganisation of porifera. 5
- Suggestion that this is possible due to spicules 2. break up sponge which reforms after a while 3. strange behaviour for animals based on self-recognition 4. if you break up 2 sponges and mix, the 2 original sponges reform 5. like systems used in immunity
What work did Werner Muller do on the work of self-identification in 2003? 3
- studied rate of cell-cell adhesion molecules 2. argues that identification is vital for an animal, leading to histoincompatibility 3. development is involved - what cells go where
What important genes do sponges have concerning their multicellularity? 3
- Hedgehog gene involved in metazoan development 2. absent in sponges, but elements are present 3. Hedge domain present as part of transmembrane protein, allowing self-identification
What level of immunity do sponges have? 4
- evidence suggests sponges may have a primitive immune system 2. autografts of tissue lead to fusion 3. allografts lead to rejection of tissue 4. if immunosuppressant FK506 (from humans) is added to water, allografting succeeds
What is the sponge’s immunity pathway like, with and without the addition of FK506? 5
Describe the Cladorhizidae familty. 9
- deap sea hexactinellida
- food poor environment therefore carnivorous
- small crustaceans captured on spicules
- cells curl around prey leading to phagocytosis
- the harp sponge is a member of this family
- Waits for dead animals eg. whales and sharks to sink
- lives off snow (detritus) - bits that float down towards ocean floor
- little movement
- glass like spicules
How are sponges being used in biomimetics? 2
- spicules are inspiring new technologies
- scientists trying to develop something like the organic glue that holds them together
How do sponges reproduce?
- in harsh conditions (lack of food,cold) may reproduce asexually by budding
- gummules contain totipotent cells called archaeocytes that become other cells, produced by asexual reproduction
- sexual reproduction is usually monoecious
- choanocytes ohagocytose sperm released into water, fertilisation then release of larvae (plankton)
- or, sperm and oocytes can be released into the water
- this is species dependent
- caclarea and some demospongiae show inversion in development
How do larvae survive and grow? 3
- fertilised, floating embryos are not actively motile, but dispersed
- most are eaten
- larva settles and grows in different shapes
How are blocked ostia cleared? 6
- Hexactinellida stop flagellation, which stops water flow
- calcium transmitted through syncytium
- demospongiae and calcarea complress flagellate chambers and contract canals
- E. muelleri (demosponge) sneezes
- glutamate causes behaviour, GABA and NO are also involved
- shows that spongees share our behavioural organization
What is the relevance of potassium channels in sponges? 3
- sponges lack neurones
- have potassium channels in oocytes
- can be inhibited
What are the neuroactive substances in porifera? 4
- T. wilelma shows rhythmic contractions
- these are affected by 5-HT, GABA, NO, glutamate and cAMP
- these are all used in the nervous system or second messengers
- these compounds are significant as thhey suggest behavioural organization
What are the symbioses with porifera? 5
- bacteria often live in mesophyll
- some photosynthetic, others methanotrophic, may be eaten
- many bacteria common to several species
- changes in canal flow may lead to altered bacterial activity
- bacteria could release glutamate, producing contractions for sneezes
Describe the neurones and genes of sponges. 6
- do not have true neurons
- neurogenic genes are expressed in specific areas of sponges eg. amphimedon during embryonic stages
- these determine organisation
- AmqbHLH1 expressed in xenopus and drosophila has proneural activity
- this allows tracing of evolution using 1 gene
Why aren’t sponges eumetazoa? 7
- no neurons
- no musculature
- lack of cell junctions so no neuronal communication
- no gut
- no front
- no reproductive organs
- no organ level specialisation
Hiddden biology of sponges and ctenophores. C Dunn at al. 2015. trends in ecology and evolution.
What clades of animals exists and how are they related to today’s more advanced animals? 3
- All animals today belong to:
Porfiera
ctenophora
placazoa
cnidaria
bilateria
- ctenophore or porifera is the sister group to today’s animals
Hiddden biology of sponges and ctenophores. C Dunn at al. 2015. trends in ecology and evolution
Describe the phylogenetic placement of sponges and ctenophores. 2
- morphological interpretations placed porifera as sister group, but recent analysis suggests otherwise, based on molecular studies.
- some evidence to support parahoxoza clade, incl. placozoa, cnidaria and bilaterians
Hiddden biology of sponges and ctenophores. C Dunn at al. 2015. trends in ecology and evolution
Describe ctenophore biology. 9
- carnivores
- most pelagic, some benthic
- reduced, derived mtDNA
- specific cells to capture prey (colloblasts)
- gravity sensing organ, opsins and pressure sensors close together
- rotational symmetry
- endoderm, ectoderm and in middle, mesoglea - not mesoderm
- some have striated muscle
- species only radiated recently so hard to link ctenophore common ancestor to early metazoa
Hiddden biology of sponges and ctenophores. C Dunn at al. 2015. trends in ecology and evolution
Describe some factors of sponge evolution. 4
- morphology appears strange but genome similar to other animals
- collared cells considered syanomorphy of choanoflagellates and animal that many animals lost, all except sponges. superficially similar
- this used to evidence sponges being a sister group
- use GABA and glutamate signalling over nerve cells
Hiddden biology of sponges and ctenophores. C Dunn at al. 2015. trends in ecology and evolution
Why is diploblast a poor term to describe porifera, placazoa and ctenophores? 1
- all have things that resemble 3rd layers that aren’t mesoderm
Animal diversity. Hickman et al. 2012.
Describe some differences between sponges.
- some are radially symmetrical
- many show no symmetry
- a new sponge class was recently determined called homoscleromorphs, from a demospongiae subset
- these have simple or no spicules
Animal diversity. Hickman et al. 2012.
Describe some ecological points about sponges. 2
- sponges lack predators, therefore are successful
- shallow - water sponges may be grazed on by fish
Animal diversity. Hickman et al. 2012.
Describe the form and function of sponges. 8
- chaonocytes line canals, create currents
- spongocoel - large cavity in asconoids for water
- homoscleromorpha have true tissues and pinacocytes make up epithelial and has basement membrane
- choanocytes engulf food particles and pass them to archaeocytes for digestion
- respire and exctrete by diffusion
- sexual cells are produced by other cells eg. choanocytes become sperm and choanocytes or archaeocytes can become eggs
- in poor conditions, some sponges produce gemmules that can be stored in harsh conditions
- released when conditions are improved
