Porifera, Cnidaria and Cetnophora Flashcards
what group do porifera belong to?
metazoa
what are Porifera?
sponges
how many porifera species?
5500
what do porifera lack?
true tissue
How many Cnidaria species?
10,000
Cnidaria characteristics? tissue/symmetry etc
true tissue
radial symmetry
diploblastic
variation in body plan
no brain
nerve net for movement coordination
what does diploblastic mean?
2 germ layers - endoderm and ectoderm
examples of cnidarians
corals, anemones and jellies
barrel jellyfish
cnidarian muscle and nerve net
bundles of microfilaments arranged into contractile fibres in the epidermis - allows response to external stimuli
how do cnidarians feed?
carnivorous
tentacles capture prey, passed to gastrovascular cavity
extra-cellular digestion
what is a homologous trait for cnidarians?
capsule like organelles
what are nematocysts?
specialised cnidae that produce stinging threads that penetrate body wall of prey
Modern Cnidaria divided into 4 classes, what are they?
anthozoans
hydrozoans
scyphozoans
cubozoa
what is polyp?
a type of body plan, attached to substrate with tentacles on the top
what is medusa?
a type of body plan that is mobile in form with tentacles at the bottom
characteristics of hydrozoa
e.g hydras and hydroids
alternate between polyp and medusa stages
hydra = highly regenerative, don’t show senescence
characteristics of scyphozoa
‘jellyfish’ - true jellies and sea nettles
all marine
most larger jellyfish (2m diameter)
medusa = most prominent
bioluminescent
characteristics of cubozoa
box jellies and sea wasps
all marine
strong swimmers
active hunters
toxins target vertebrates - potent venom
characteristics of anthozoa
flower animals
corals and anemones
only occur as polyps
lots of nutrition via photosynthesis
what are ctenophores?
comb jellies - e.g sea gooseberry
how many species of ctenophores?
roughly 100
characteristics of ctenophores
all marine
radial symmetry
diploblastic
long branched tentacles with colloblast cels (sticky)
all hermaphrodites
many bioluminescent
