Chapter 32, and Sponges/Cnidarians Flashcards
Give a few characteristics of animals (11 possible)
Heterotrophic, nervous and muscle tissue, multicellular, tissues developed from embryoic tissues, eukaryotes, no cell walls, sexual reproduction, at least one larval stage, developmental (Hox) genes, all animals share a common ancestor
Define bilaterally symmetric and give the unique traits, movement, and number of embryonic tissues
Have a dorsal/ventral side, a right/left side, and anterior/posterior ends
Most have nervous system located in the “head”
Can move faster than a radial organism
All are triploblastic
Define radially symmetric and give the movement style
Have a top and bottom, but no front/back or left/right
Often sessile or planktonic
Define ectoderm
Ectoderm covers the embryo’s surface
Define endoderm
Endoderm lines the developing digestive tube
Define diploblastic
Diploblastic animals have only ectoderm and endoderm
Define triploblastic
Triploblastic animals have mesoderm as well as ecto/endoderm
Define coelom. Which animals do not have a coelom?
a true body cavity derived from mesoderm
Include everything except roundworms, rotifers, and flatworms
Define acoelomates. What group do they contain?
lack a body cavity
Include flatworms
Define pseudocoelomates. What groups do they contain?
have a body cavity that is not lined with mesoderm (still functional)
includes roundworms and rotifers
What is the function (3) of a body cavity?
Fluid that cushions the suspended organs and provides a ‘skeleton’ for muscles
Enables internal organs to grow and move independently of the outer body wall
Protostome or Deuterostome?
Spiral and determinate cleavage
P
Protostome or Deuterostome?
mouth develops from blastopore
P
Protostome or Deuterostome?
anus develops from blastopore
D
Protostome or Deuterostome?
solid masses of mesoderm split and form coelom
P
Protostome or Deuterostome?
folds of archenteron form coelom
D
Protostome or Deuterostome?
radial and indeterminate cleavage
D
What animals are protostomes?
Flatworms (platyhelminthes), Rotifera, nematodes, most mollusca, most annelids, a few arthropods
What animals are deuterostomes?
Echinodermata, Chordata, Most arthropods, a few molluscs and annelids
What defines the eumetazoa clade?
having tissues
What three major groups make up the eumetazoa clade?
deuterostomia, ecdysozoa, and lophotrochozoa
What are the members of the deuterostomia clade?
Hemichordates (acorn worms), Echinoderms (sea stars), and Chordates
What defines the ecdysozoa clade?
Secrete external skeletons, which are shed through ecdysis
What defines the lophotrochozoa clade?
Feeding structures called lophophore
(horseshoe-shaped and ciliated)
and/or Distinct developmental stage of a trochophore larva (Short-lived)
Resemble corals
What is the tissue type and symmetry of porifera?
Lack tissues and organs, asymmetrical
Where are porifera in the phylogeny of animals?
They are the basal animals and the sister group to all other animals
Describe the sexual traits of porifera.
Most are hermaphrodites
What makes up the ‘skeleton’ of porifera (two types)?
Structural protein is collegen, a specialized form is spongin
spicules are made of caco3 or si, and are used to classify sponges
What is the ecological significance of porifera?
Symbiotic relationships with algae, bacteria, fish, and invertebrates
Important members of shallow reefs, form deepwater reefs
Boring sponges can injure coral
What drugs come from porifera?
A chemotherapeutic drug for leukemia, Ara-C/cytarabine is derived from spongothymidine
Define spongocoel
the central cavity of sponges
Define osculum
the large opening where food exits in sponges
Define choanocytes
the flagellated collar cells in sponges that make water currents and ingest food
Define mesohyl
the gelatinous noncellular layer found between two cell layers in sponges
Define amoebocytes
found in the mesohyl, move around and phagasitize food
Describe the symmetry and tissue type of cnidarians
diploblastic, radial
Where are cnidarians in the phylogeny of animals?
They are one of the oldest groups in the eumetazoa clade
Describe the movement and forms of cnidarians
Sessile (polyps are stationary)
Both polyp and medusa forms
Advantages-> good at doing different things
Jellyfish are only medusa
What are the two major clades of cnidarians?
medusozoa and anthozoa
What are the three clades of medusozoa?
hydrozoans, scyphozoans, and cubozoans
What are the characteristics of medusozoans?
Dominant medusa stage
What are the characteristics of hydrozoans? What are some examples?
Most alternate between polyp and medusa forms
Hydra exists only in polyp form
Portuguese Man-of-War looks like a jelly
What are the characteristics of cubozoans? What are some examples?
Sea wasp
Highly toxic cnidocytes
What are the characteristics of anthozoans? What are some examples?
include sea anemones and corals
Only have polyp stage
Symbiont with algae/dinoflagellates and secrete a hard CaCO3 exoskeleton
Give some threats to coral reefs
Coral reefs are under threat from excess nutrients, siltation, overfishing, toxic chemicals, ocean acidification, and global warming
Define gastrovascular cavity
central digestive compartment in cnidarians
Define cnidocytes
cells that function in defense and capture of prey
Define nematocysts
specialized organelles within cnidocytes that eject a stinging thread
What are some characteristics of scyphozoans?
Coastal have a brief polyp stage, open ocean has none
