Chapter 33-Noncoelomate and Pseudocoelomate Invertebrates Flashcards
What is in phyla porifera
sponges
What are parazoa
Simple animals lacking tissues, most lack a definite symmetry (asymmetric)
Larval sponges
Free swimming motile
Adult sponges
remain attached-sessile
How does water enter and exit a sponge
enters through ostia and exits osculum
What is the mesohyl (middle layer) of a sponge made of
- spicules-needles of calcium carbonate or silica
- spongin-reinforcing tough protein fibers
What are choanocyte
they engulf and digest food from passing water
-collar cells-move water through sponge; absorb nutrients
How do sponges asexually reproduce
fragmentation-piece breaks off and attaches elsewhere to form new sponge
Describe sexual reproduction in a a sponge
Hermaphrodite
- choanocytes transform into sperm
- captured and passed to egg cell in mesohyl
- development can occur in mother or in open water
What layer of a sponge provides protection
Mesohyl
What are Eumetazoa
All animals except sponges-distinct tissues
what type of symmetry do Cnidaria exhibit
Radial symmetry
What are organisms called with only 2 germ layers
diploblastic
What are nematocysts
stinging cells found on tentacles of cnidarians
What are the 2 forms of Cnidarians
Polyps: cylindrical and sessile
Medusa: umbrella-shaped and motile
what does the gastrovascular cavity do for the cnidarian
gives it a hydrostatic skeleton to support itself with
What are Anthozoans
Cnidaria
sea anemones, corals
-all polyps
What are Cubozoa
Cnidarians
-box jellies, strong swimmers, fatal stingers
What are hydrozoa
Cnidarians
- hydra, portuguese man of war
- both polyp and medusa forms, has freshwater members
What are Syphozoa
Cnidarians
- Jellyfish
- ring of muscle allows for rhythmic contractions for propulsion
What are staurozoa
Star jellies
-resembles a medusa in most ways but is attached to substrate
Describe Phylum Ctenophora
Comb jellies
-radial symmetry
8 rows of fused cilia that beat in coordination
-bioluminescent
What do Ctenophores use to capture prey
2 tentacles covered with Colloblasts
-discharge strong adhesive used to capture prey
How are bilaterians classified
by their coelom
- acoelomates
- pseudocoelomates
- coelomates
What phylum are flatworms in
Platyhelminthes
Describe flatworms
Ciliated, bilaterally symmetrical, Acoelomates, many are parasitic
What do Platyhelminthes lack
A circulatory system
-simple diffusion for gas transport
what category are tapeworms in
Platyhelminthes
how do tapeworms absorb their food
directly through body walls
What do flame cells do for Platyhelminthes
help with excretion of fluids and other substances
How do platyhelminthes reproduce
most are hermaphroditic,
can undergo sexual reproduction
asexual regeneration
what are the 2 major groups of flatworms
Class Turbellaria-free living
Neodermata-parasitic
-class trematoda-flukes
-class cercomeromorpha-tapeworms
What is one of the most important trematode to human health
blood flukes
How do tapeworms stay in the body
hang onto inner wall of host intestine using scolex
Describe Phylum Acoelomorpha
Have primitive nervous system and lack digestive cavity
-once considered part of platyhelminthes
Describe Cycliophora (phylum)
Acoelomates
- live on mouthparts of claw lobsters
- circular moith surrounded by ring of cilia
What does the Pseudocoelomic fluid do
performs the fuctions carried out by a circulatory system in most coelomate animals
What are in Phylum Nematoda
Nonsegmented, round worms
-marine, freshwater, parasites, free-living
Nematode characteristics?
Bilaterally symmetrical and unsegmented
-Pseudocoelom
How do Nematodes reproduce
Separate male and female worms
-smaller males have a hooked end
Lifestyle of nematodes?
Many are active hunters
-others are parasites of plants and animals
What are in Phylum Rotifera
Bilaterally symmetrical, unsegmented pseudocoelomates
- highly developed internal organs
- conspicuous ring of cilia at anterior end used for locomotion and sweeping food into mouth
