Chapter 28 Flashcards
what characterized clade parazoa?
no tissues, body cavity, or symmetry
who are members of phylum porifera and where are they found?
sponges; marine and freshwater
are sponges free swimming or sessile?
larvae free swimming, adults sessile
list and describe the 3 layers of sponge body walls
- inner layer: specialized cells, for feeding
- middle layer: gelatinous, protein rich matrix called mesohyl, may contain spicule or spongin
- outer layer: protective epithelial cells
what is the space inside the sponge called?
spongocoel
what are the pores in the outer layer of a sponge called and what do they do?
ostia, let food and water inside
list the 3 sponge body types, in order from simplest to most complex and most surface arearelease of gamet
ascenoid, syconoid, leuconoid
what is the role of the choanocyte flagella in porifera?
keep wtaer moving for the filter feeding
how does sponges reproduce?
asexually: through fragmentation and
sexually: through release of gametes for random mating
what do larval sponges use for swimming?
cilia
what 2 clades are in eumetazoa?
radiata and bilateria
list the symmetry and body cavity of radiata
radial symmetry and no body cavity
what 2 phyla are in clade radiata?
cnidaria and ctenophora
where are cnidarians found?
nearly all marine
do cnidarians have tissues?
yes but no organs
discuss the tissue layers of cnidarians
diploblastic, layer of gelatinous material, or mesoglea between endo and ectoderm
what is the cnidarian diet?
carnivorous
what are the 2 basic body forms of cnidarians?
medusa and polyp
how do polyps reproduce?
either sexually or asexually by budding
how do medusae reproduce?
sexually, making free swimming larvae called planulae
how does digestion work in cnidarians?
internal extracellular digestion; enzymes are released to break down food, then extracellular fragmentation in the gastrovascular cavity, followed by phagocytosis and intracellular digestion
how is circulation, respiration, and excretion accomplished in cnidarians?
through diffusion bc no organs
what are the unique,specialized cells on the epidermis of cnidarians?
cnidocytes
what are the specialized stinging cnidocytes?
nematocysts function in food acquisition and defense
list the 4 classes of cnidarians
- hydrozoa
- scyphozoa
- anthozoa
- cubozoa
what is the only class of cnidarians with both marine and freshwater species?
hydrozoa
what form of hydrozoa is the portugese man of war?
colonial
why are anthozoas only found in shallow water?
because of the symbiotic relationship with the photosynthetic algae in their tissues
what do anthozoas secrete?
reef building calcium carbonate
how do anthozoas eat?
strictly carnivorous
what other animal do sea anenome have a symbiotic relationship with?
clown fish
what are the 2 kinds of platyhelminthes?
free living flatworms (Turbellaria) parasitic flatworms (Termatoda and Cestoda)
describe the digestive aspect of platyhelminthes
incomplete digestive tract in turbellaria, no digestive cavity in trematodes and cestodes
do platyhelminthes have an excretory system?
yes, but primitive
discuss a hallmark aspect of platyhelminthes nervous systems
eyespots that can sense light and dark
how do platyhelminthes move?
ciliated epithelial cells, musculatura
how do trematodes and cestodes absorb nutrients without a digestive cavity?
directly through body walls
describe the excretory system of platyhelminthes
network of fine tubules, with flame cells
discuss the role of flame cells in platyhelminthes
located on the side branches, primary function is water balance, secondary function is excretion
how are metabolic wastes excreted in platyhelminthes?
directly into the gut and out through the mouth
why do platyhelminthes lack a circulatory system?
not a lot going on, flat enough that diffusion works instead
describe the reproductive aspects of platyhelminthes
most monoecious (hermaphroditic), but undergo sexual reproduction, and have the capacity for asexual regeneration
what interprets the information from the eyespots of platyhelminthes?
a primitive nerve cord
list the 3 classes of platyhelminthes?
- turbellaria
- cestoda
- trematoda
what are turbellaria and where are they found?
free living flat worms found in marine, freshwater and terrestrial environments
what are trematoda and where are they found and also describe their lifecycle
flukes that live as ecto or endo parasites in the bodies of other animals, have a lfiecycle that involves 2 or more hosts
what happens in the definitive host?
where adult form of parasite lives and produces eggs, sexual reproduction, eggs are released into the environment and picked up by the intermediate host
what happens in the intermediate host?
where parasites live in larval form and reproduce asexually
what is the paratinic host?
the transport host, where no reproduction takes place
who are cestoda and where are they found?
tapeworms, live as parasites in the bodies of other animals, mostly in the intestines of vertebrates
list and describe the 3 zones of the cestoda body
scolex: attachment organ
neck: unsegmented portion
proglottids: reproductive sections, each is a complex hermaphroditic unit
what is the beef tapeworm?
Teania saginata
how do cestoda eggs get into the environment?
the proglottid segments break off and come out through the feces of the direct host
how do you break the parasite lifecycle?
treat the intermediate host
what is a pseudocoel?
a cavity between the mesoderm and endoderm
how does the pseudocoel function?
as a hydrostatic skeleton, against which the animal’s muscles can work
do pseudocoelomates have a circulatory system? why or why not?
no, the function is performed by the fluids that move within the pseudocoel
who are the pseudocoelomates?
phyla rotifera and nematoda
who are nematodes? symmetry? segmentation
roundworms, bilateral, unsegmented
whatbody plan do nematodes have?
tube within a tube
what are nematodes covered with that they must molt in order to grow?
a thick flexible cuticle that serves as oxygen exchange
describe the reproductive stuff of nematodes
dioecious, very obvious repro tract
what are the piercing organs on nematode mouths?
stylets
how does food pass through the mouth of nematodes?
the sucking action of the pharynx
what phylum does the canine heartworm belong to?
nematoda
what are rotifera?
bilateral unsegmented pseudocoleomates with complex internal organs
