annelids Flashcards
do annelids have coelums
yes
what is a coelum in annelids
a fluid filled body cavity that allows space for expansion and development of visceral organ systems
where are annelids found
in a huge variety of habitats, including the extremes. eg glacial worms
what are the feeding modes of annelids
suspension feeder, herbivory, carnivory
how many differentiated areas do annelids have
3 areas: the prostomium (head), segmented trunk (has chaetae), and pygidium (posterior end - anus)
where do segmented structures originate from in annelids
from the growth area above pygidium (during development or juvenile only)
what does segmentation allow annelids to do
allows diversification of possible forms, and allows greater flexibility and movement
what is the external cuticle made up of and what does this allow
collagen that is never shed, allows structural toughening and is protective. however this affects permeability
what does chaetae do in annelids
creates traction and other aspects of locomotion under muscular control
what does the external cuticle cover in annelids
monolayer of glandular epidermis that secretes material that forms a protective tube
what is under the glandular epidermis in annelids
connective tissue and 2 layers of muscle
what is the 2 layers of muscle under the galndular epidermis called and what are they
circular muscle that is a continuous sheath and longitudinal muscle that is present in many species as 4 distinct bands
what is included in an annelids nervous system
a “brain” cerebral ganglion, a ventral nerve cord connected to brain by cricopharyngeal connectives.
where are the primary unicellular receptors in annelids and what do they sense
on head, palps and antennae, and they sense light and chemo-mechano
what are nuchal organs in annelids
ciliated eversible chemosensory structures that are characterised by polychaetes
what type of circulatory system do annelids have and what does it do
a closed circulatory system that transports oxygen and nutrients through the body
what is the respiratory pigment in annelids
haemoglobin that is pumped through vessels to the muscular heart(s)
what is the annelids digestive system like
a straight tube from mouth to anus, integrating the separate body
what are the feeding modes of annelids
direct deposit feeder, indirect deposit feeder, filter feeder, herbivores, carnivores, blood feeders
how to leaches feed
blade like jaws for cutting skin, salivary glands secrete anticoagulants.
what forms of asexual reproduction does annelids show
fragmentation, budding, fission and clonal reproduction
what is epitoky in annelids
specialised pattern of transverse fission budding in posterior region, leading to production of pelagic reproductive form from benthic feeding form
are epitoky genetically identicle
yes, but morphologically distinct
how do marine annelids sexually reproduce
many marine annelids have 2 sexes and exhibit external fertilisation via mass spawning,
how to terrestrial annelids sexually reproduce
internal fertilisation, most are hemaphorditic. clitellates have reproductive structure around female gonopores. eggs produced
what type of symmetry do annelids have
are bilaterally symmetrical
