lecture 4 invertebrates (non-arthropods): molluscs & annelids Flashcards
what does the phylum mollusca mean in latin
soft
examples of species in the mollusca
snails clams octopussies
mollusca symmetry type
bilateral
mollusca (a)coelomates?
coelomates
four types of mollusc body plans
gastropods, cephalopods, bivalves chitons
what does the class bivalvia mean in latin
bi = 2 valvia = valve
what are bivalves
Aquatic animals with two shell valves (bi-lateral symmetry)
Mostly sedentary or burrowing
bivalve adaptations
greatly expanded gills for filter feeding and respiration
bivalve sex
Separate sexes, fertilisation is external & free-swimming larva
what does the class gastropoda mean in latin
gastro = stomach poda = feet
where do gastropods live
terrestrial and aquatic
gastropod adaptations
Head well developed for finding food; eyes, tentacles etc.
Asymmetrical body due to shell coiling & torsion
some have lost or reduced shell
what is torsion
twisting of the body in relation to head & foot brings the anus above the head
what type of eaters are gastropods
Herbivorous, carnivorous or scavengers
what are gastropods, sexually?
seperate sexes OR hermaphrodites
how do snails mate
Elaborate and slow mating ritual
exchange sperm and a ‘love dart’ – mucus covered calcareous dart
they have their genitals near their heads
what does the class cephalopoda mean in latin
cephalo head
poda feet
what type of animal are cephalopods
Marine predators
Integral head & foot; tentacles, usually with suckers
whats special about the shell of cephalopods
Shell usually internal; “cuttlebone” of Sepia provides support & bouyancy
how are squids(cephalopods) adapted for fast swimming
Squids have elongated body, fins & ”jet propulsion” for fast swimming
cephalopods wheres the brain and whats special about it
in the braincase
highly developed and sophisticated behavior
cephalopods sex
seperate sexes with courtship displays
what does sthe phylum annelida mean in latin
annel = ringed
what kinda species are annelids
Fan worms, bristle worms, earthworms & leeches
annelids, what are they like?
Bilateral symmetry and segmented body
Body covered with chaetae (bristles used for movement)
annelids (a)coelomates?
coelomates
coelomate advantages
hydrostatic skeleton
transport of excretory and sexual products
annelids have metameric segmentation, what is this
allow independent movement of different portions of muscles.
where do annelids live
Marine, fresh water and terrestrial species.
how do annelids reproduce
sexual and asexual reproduction
what are the three classes of annelids
polychaeta
oligochaeta
hirudinea
what does the class polychaeta mean in latin
many bristles
what are polychaetes and examples
Marine annelids
Mobile and sedentary species
fan worm
bristleworm
lugworm
what are the oligochaetes and examples
terrestrial and aquatic annelids
Few bristles
earthworms
sludgeworms
what is a hirudineate
Ectoparasites or predators
Few bristles
Some blood suckers
eg leeches
what clades has new genetic evidence brought
errantia
sedentaria
what are the errantia
mobile marine predators
that craw or burrow on the seafloor
what are the sedentaria
marine sedentary worms
earthworms leeches
what does errantia mean in latin
errant = travelling
what are some morphological features of errants
Well defined head with eyes and jaws
Each body segment with prominent parapodia
how do errants reproduce
Sexual reproduction with separate sexes
sexes in sedents
hermaphrodites
what is metameric segmentation
The repetition of organs and tissues at intervals along the body of an animal, thus dividing the body into a linear series of similar parts or segments
