what species belong to annelida
segmented worms
where do annelida live
marine, freshwater, terrestrial
how do they eat
suspension feeders, predators, parasites and detritrovors
what are the three groups of annelida
- polychaete
- oligochaete
- hirudinea
many polychaete have Chaete, what is this?
lots of hairs on their bodies
what is the polychaete body plan like?
- metamere structures are confined to trunk
- head has specialised sense organs
- chitinous jaw
- have fleshy appendages that extend from body facilitating movement/ locomotion
what is the brain like in polychaete?
- lies in the prostomum
- rapid contraction to avoid predetors aided by giant axons
what are the sense organs of polychaetes like
- pigment cup eyes: detects light intensity
- nuchal organs: chemoreceptors
- statocytes: detect change in orientation
what is reproduction in polychaete like
- asexual reproduction
- no permanent sex organs
- fertilisation is external
what species belong to the oligochaete group
earth worms
oligochates reproduction
- mutual sperm transfer
- clitellum secretes mucus coat to hold worm in position- also secretes chitin material to form cocoon for fertilisation
what is the locomotion of oligochates like
- longitudinal and circular muscles
- waves of contraction pass down length of body causing elongation and shortening in each segment
- they burrow
- reduced sense organs
what species are in hirudinea group
leeches
what is the feeding style of leeches
predetors
where are the suckers on a leech
on the anterior and posterior end
what are the challenges of the leeches life style
- accessing blood
- finding a host
- evading hosts defences
-keeping the hosts blood flowing
medical uses of leeches
- blood letting
- local anaesthetic and anti inflammatory
- promote blood flow
- saliva contains proteins
- used to treat blood clots
