This is the ____ class in the phylum annelida
largest
Mostly live in what habitat?
marine
There is ____ in only some of the somites.
differentiated
There is more specialization of sensory organs than in the class ____.
clitellates
They can tolerate a wide range of what?
salinity
Freshwater polychaetes tend to live in ___ regions
warmer
They inhabit what ? (3)
- crevices, tubes, or are pelagic
They have a well differentiated ___ with ___ organs.
head, sense
They have paired appendages called ___ on most segments.
- parapodia
- many setae are bundled on these
Do they have a clitellum or not?
not
Errant polychaetes travel via ? (3)
free moving, burrowing or crawling
Prostomium:
- may or may not be___?
- Often bears what three things?
- It surrounds the ___ and may have what three things?
- retractile
- eyes, tentacles and sensory palps
- mouth, setae, palps, or chitinous jaws
Ciliary feeders may bear a _____ that opens like a fan but can be withdrawn into the tube.
tentacular crown
Most segments of trunk bear _____ with lobes, cirri, setae and other parts.
parapodia
Parapodia explain it !
aid crawling, swimming and anchor worm in a tube
- usually the chief respiratory organ although the worm may also possess gills ( Amphritite and arenicola)
Nutrition:
- Polychaetes have what three things that aid in digestion etc?
- foregut, midgut and hindgut
Nutrition:
Foregut?
- has a stomodeum, pharynx, anterior esophagus lined with cuticle
Nutrition:
Midgut?
- derived from the mesoderm secretes enzymes and leads to anus on the pygidium
Nutrition:
Short hindgut ?
- derived from the ectoderm and leads to anus on pygidium
Errant polychaetes are what kind of food acquirers?
- predators or scavengers
sedentary polychaetes feed on what?
suspended particles or particles in sediment
For respiration most have a ___ and ___ for gaseous exchange while others use the ___.
- parapodia , gills, body surface
Circulation varies:
In Nereis a ____ carries blood forward and a ___ carries blood posteriorly.
dorsal blood vessel
ventral blood vessel
- blood flows across between these major vessels in networks around the parapodia and intestine
Circulation:
In some, ___ are incomplete and _____ serves circulatory function.
- septa
- coelomic fluid
Many polychaetes have respiratory pigments. Which can be what? (3)
- Hemoglobin, chlorocruorin or hemerythrin
Excretion:
- The organs vary from ___ to ____ and some mixed forms
- There is ___ per metamere
- The inner end also called a _____ opens into the coelomic cavity
- Coelomic fluid enters the ___
- Selective reabsorption occurs along what?
- protonephridia, metanephridia
- one pair
- nephrostome
- nephrostome
- nephridial duct
Reproduction and development ?
- Do they have permanent sex organs?
- Monoecious or Dioecious?
- Gonads appear as what?
- Gametes are shed into coelom and exit by____, ____, or ____.
- Fertilization is ___ and the early larva is a ___.
- no
- monoecious
- temporary swellings of peritoneum
- gonoducts, metanephridia or rupturing of the body
- external, trochophore
What are epitokes? Atoke?
- packed with gametes and detach then rise to surface and release gametes.
- normal portion of the annelid
Instead of transforming a portion of body into epitoke some will ?
- bud off complete worms that become epitokes
What are some representatives of the class Polychaeta ? (5)
- Clam worms (Nereis), fire worms, tube worms, fan worms, parchment worms
Clam worms (Nereis) :
- they are ___ polychaetes
- They live in mucus lined burrows near ___
- Prostomium bears what? (3)
- Peristomium has what? (3)
- errant
- low tide level
- a pair of palps sensitive to touch and taste, a pair of short sensory tentacles and two small dorsal eyes sensitive to light
- ventral mouth, pair of jaws, four pairs of sensory tentacles
Clam worms (Nereis) continued: *Parapodia L> contains two lobes what are they? L>acicula are? L>What assits respiration? L>Movement via? (2) L>What kind of muscles are in each somite? L>What movements provide free swimming and burrow pumping actions ?
- dorsal notopodium and ventral neuropodium
- one or more chitinous spines that support each lobe
- abundant blood vessels
- oblique
- undulatory
What do clam worms feed on?
Food is moved through alimentary canal via?
small animals, other worms and larval forms
peristalsis
Fireworms:
Poisonous secretions are found where?
what do they feed on?
- hollow, brittle setae
- cnidarians
Tubeworms:
- They dwell in?
- many line their burrows with what?
- They use what to obtain food? (2)
- They live in very __ habitats
- tubes
- mucus
- cilia or mucus
- extreme , deep open vents
Fanworms:
- have what to aid in feeding?
- unfurl tentacular crowns
Parchment worms:
- Lives in a ?
- What do their modified segments do?
- U-shaped tube
- pump water through tube ( extracting food)