Annelids

metameres

metameres

serially repeated units of annelid bodies

septa

partitions between metameres

allows independent movement of segments

how does metamerism increase burrowing efficiency?

annuli

circular grooves that mark metameres

setae

tiny chitinous bristles found in most annelids but absent in leeches

Oligochaetes

scientific name for earthworms

hirudinids

scientific name for leeches

polychaetes (bristle-worms)

chiefly marine and mostly benthic; some are pelagic in open seas

prostomium and peristomium

2 parts of annelid head

pygidium

terminal portion of annelid bearing anus

in front of pygidium

where do new metameres form

peritoneum

mesodermal epithelium that lines body wall and \n forms dorsal and ventral mesenteries that cover all organs

schizocoely

how does annelid coelum form?

non-chitinous

what type of outer cuticle do annelids have?

no

is the annelid digestive system segmented?

clitellum

unique reproductive structure called a that is a ring of secretory cells found in a band around the body about one-third of the body length from the front end

hermaphroditic

how are members of clade clitellta classified reproductively?

reproductive season

when is the clitellum visible in leeches?

damp or rainy weather

when do members of clade clitellata remain on the surface?

circular muscles

contractions of these muscles in the anterior end of earthworms lengthen the body to push the anterior end forward.

longitudinal muscle

contraction of these muscles follows earthworm anchoring to shorten the rest of the body and pull the posterior end toward the tail.

4

Each oligochaete body segment usually has _____ pairs of chitinous setae

scavengers

Oligochaete nutrition

calciferous glands

located along the esophagus reduce calcium ion \n concentration in the blood and regulate acid–base balance in body fluids.

prostomium

aids in handling of oligochaete food

crop

thin walled area for food storage in oligochaetes

typhlosole

increases absorptive surface area

chloragogen cells

surround the intestine and synthesizes glycogen and fat much like a liver; can also have excretory role

closed

what type of circulatory system do oligochaetes have?

ventral vessel

\n serves as oligochaete aorta, delivers blood to brain, body walls, nephridia, and digestive tract

no, gases are exchanges across body surface

do oligochaetes have respiratory organs?

nephrostome

A ciliated funnel found anterior to intersegmental septum

nephridiopore

where does the nephridial duct empty to the outside?

metanephrida

\n Each somite, except the first three and terminal one, have a pair of ________ that occupies parts of the adjacent somite.

ammonia, urea

Aquatic oligochaetes excrete toxic ___ while terrestrial worms excrete less toxic ______

chloragogen cells

produce urea and ammonia

yes both

do oligochaetes have a central nervous system and peripheral nerves?

cerebral ganglia

connect around the pharynx to the ganglia of the ventral nerve cord running along the floor of the coelom

neurohormones

secreted by neurosensory cells in the brain and ganglia to regulate reproduction, secondary sex characteristics, and regeneration.

photoreceptors

lens shaped appendages in oligochate epidermis that act in place of real eyes

free nerve endings

tactile structures in integument to sense the surroundings

monoecious

are earthworms monoecious or dioecious?

9-15

In what segments of Lumbricus are the reproductive structures located?

seminal groove

Place along which sperm from each worm is transported to the seminal receptacles of the other

ventral

what surfaces of earthworms align during reproduction?

sexual maturity

when do young worms develop a clitellum

freshwater

most common leech environment

carnivores or parasites

nutrition of leeches

transverse grooves

form superficial annuli that make leeches appear to have more segments than they really do

suckers

used in leeches for attachment to host

septa

what do leeches lack that makes them lack distinct coelomic compartments?

proboscis

found in freshwater leeches for ingesting small invertebrates as well as to suck blood from soft tissues

cutting plates or chitinous jaws

found in leeches considered to be true bloodsuckers, used to penetrate through tough skin

anticoagulant

enzymes secreted from leech salivary glands to keep blood flowing

skin

where does gas exchange occur in leeches?

hermaphroditic with cross fertilization

how is leech reproduction classifies

no

is segmentation among annelids, arthropods, and chordates thought to be homologous?

trophosome

structure that houses leech bacteria in extreme environments