Flashcards in Flatworms part 2: Gnathifera, Ectoprocta and Nemertea Deck (42):
Which phylum has:
Complete digestive system (mouth to anus), salivary and gastric glands
Dioecious (males smaller than females), some males unknown
Females with paired ovaries, parthenogenic reproduction in some.
The rotifer excretory system of has a pair of
protonephridial tubules with flame cells that empty to common bladder
Why is osmoregulation important in both freshwater and marine species;
because water enters by the mouth during feeding.
What is included in the rotifer nervous system?
A bilobed brain is dorsal to the mastax with paired nerves leading off to the organs.
Sensory organs include eyespots, sensory bristles and papillae, and ciliated pits and dorsal antennae.
The mastax is a ____
muscular pharynx equipped with hard jaws, the trophi.
What has a funnel-shaped area around the mouth; side lobes fold inward to entrap prey.
What do hunters do?
project trophi to seize prey.
Rotiferous are dioecious this means that
with males being smaller than females which contain combined ovaries and yolk glands.
Some rotiferans are ____ which means
are parthenogenetic* and produce diploid (2N) eggs that hatch to diploid (2N) females only (diploid amictic eggs)
What type of factors can affect the eggs development of rotifers?
Environmental- in forming diploid or haploid eggs
Unfertilized haploid eggs form haploid males but if fertilized can become dormant ______ eggs with thick resistant shell that will hatch as amictic females.
Winter resistant eggs
a form of asexual reproduction
Ectoprocts are also called _____ and are different because of the location of the anus on _____ ring around the mouth
outside of the tentacular ring
Some key characteristics of Bryozoa
-no excretory, circulatory or respiratory organs
-Some are monoecious, some dioecious, and some produce sperm first and later eggs
how many living species are there in Bryozoa
Where are Bryozoa found?
Inhabit both shallow freshwater and marine habitats
Some marine colonies form limy encrustations on seaweed, shells, and rocks
Others form fuzzy or shrubby growths or erect branching colonies
Freshwater colonies may form moss-like colonies on stems of plants or on rocks
What do the aquatic animals do in Bryozoa?
often encrust hard surfaces
Most are sessile, some slide slowly, and others crawl actively across surfaces
What are the colony members called in Bryozoa- Phylum Ectoprocta and how to they feed
colony members are called zooids
feed by extending lophophores into surrounding water to collect tiny particles
also secrete exoskeleton in which they live in called zoecium
may be gelatinous, chitinous, or stiffened with calcium and possibly impregnated with sand that can be boxlike, vaselike, oval, or tubular in shape
Zooids pop up to feed but any disturbance they go into a trapdoor called
The lophophore is extended and tentacles spread out into a funnel when needing to ___
Digestion begins extracellularly in ___ and is completed in ____
in the stomach and completed intracellularly in the intestine in a complete gut system.
How do you differentiate a colonial cnidarian (coral) from a colonial bryozoa?
-Cilia on tentacles of bryozoa.
-Gastrovascular cavity continuous between coral polyps while in some bryozoa through coelomic fluid connections.
-Complete gut in byrozoa. Incomplete in coral.
Ectoprocta can have non feeding members called
Aviculariums are modified
zooids that resemble bird beaks and can snap at small invading organisms that approach the colony
have long bristles that sweep away foreign particles
Ectoprocts are mostly hermaphroditic (monoecious) and brood their eggs
brood their eggs
where does brooding occur?
within the coelom and some have an external chamber
embryos proliferate asexually from the initial embryo in a process called
Larva of _____ have a functional gut and swim for a few months before settling.
Larva of ______ do not feed and settle after a brief free-swimming existence.
In Ectoprocta new colonies begin from a single metamorphosed primary zooid, called an
Ancestrula undergoes_____ to produce many zooids of a colony
Freshwater ectoprocts undergo budding that produces ____ which are hard, resistant capsules containing a mass of germinative cells.
When do statoblasts
occur in the summer and fall that eventually give rise to zooids and later forming new colonies
What phylum is also known as ribbon worms?
What is a unique characteristic of the Phylum Nemertea
Eversible proboscis lies in free cavity (rhynchocoel) above alimentary canal
Simplest animal with blood vascular system
Adult has anus, complete digestive system
Some species detect prey when physically near and use ____ hiding in a cavity called the ____ to seize
called the rhynchocoel
Adult has an anus, producing a
complete digestive system
What has true circulatory system and blood flow is irregular due to contraction of vessels and general body movements