Sponges, Cnidarians, and Platyhelminthes Flashcards
What are sponges widely considered as?
basal animals - meaning it is sister to all other animals
What are Choanoflagellates (in relation to animals)?
sister taxon of animals
ancestral to sponges
What is the other phylum that could be basal over sponges?
Ctenophores
What is the phylum name for sponges?
Porifera
WHat makes Sponges animals?
similar embryonic development
simple immune system
ion channels to make neuron function
have homologous genes required to make neurons
When did the first sponges appear?
some fossils up to 710mya
most appear just before Cambrian period 560mya
What are choanocytes?
flagellated cells that set up currents that draw water into the cavity. and ingest and process food
What is the mesohyl?
gel-like and supports cells that form spicules and generate feeding and reproductive cells
What are skeletons in some sponges made of?
sipcules made of silica, calcium carbontae, or proteins
or spongin made of protein
How do sponges gain nutrition?
intracellular digestion - the circulating water contains food particles and dissolved organic matter, with cells lining the cavity capture by endocytosis
What is significant about reproduction in sponges?
no reproductive organs, but cells that migrate n to the mesohyl and differentiate as sperm or eggs
most are hermaphrodites
Describe sexual reproduction in sponges
sperm is released and taken up by another individual; fertilized eggs develop into ciliated free-swimming larvae which eventually differentiates into an adult sponge
How can sponges reproduce asexually?
fragmentation
Describe Sponge diversity
15000+ identified species most marine around 150 freshwater
cover almost every part of ocean
75% of biomass on floor of Antarctic ocean
What differentiates Sponges from Choanoflagellates?
multicellularity, gastrulation, collagen
What differentiates Cnidarians from Sponges?
Tissues
WHta differentiates Cnidarians and Bilaterians?
Cnidarians exhibit radial symmetry
Bilatarians exhibit Bilateral symmetry and complex organs
What re distinct characteristics of Cnidarians
Radially symmetrical
2 tissue layers with non cellular jelly like material between
What re the features of the tissue layers in Cnidarians?
Outer layer is epidermis
inner layer is the endodermis which lines the gastric cavity
in between these layers is a non-cellular jelly-like material (mesoglea)
What are the types of Cnidarian body plans?
Medusa form
Polyp form
What is a Medusa form Body plan?
bell-shaped or umbrella shaped body, with the mouth directed downward
What is a Polyp form body plan?
Tubular body with the mouth directed upward
What is the nervous system in Cnidarians?
epidermis and endodermis possess nerve cells arranges in a loose network of intersecting nerves - nerve net (plexus)
How do Cnidarians obtain food?
tentacles capture prey and direct it toward the mouth; digested in the gastric cavity
gastric cavity has one opening (for food intake and the elimination of waste)
no system for internal transport, gas exchange or excretion
What is a diagnostic characteristic of the phylum Cnidaria?
stinging organelles (enidocytes)
WHat do stinging organelles of cnidarians do?
enhance prey capture
entangle prey or harpoon prey and inject a paralyzing toxin
How does asexual reproduction work in Cnidarians?
budding or pedal laceration for sea anemones
What is pedal laceration in sea anemones?
a new anemone is formed once a grown anemone moves away from an area, leaving behind some fragments of its pedal disc
What are Hydrozoans?
Class of Cnidarians
sessile (permanently attached or established)
mostly marine
most live in colonies of polyps
WHat are Scyphozoans?
class of Cnidaria
marne; free-swimming with prominent medusa (bell-shaped) morphology as adults
What is sexual reproduction in Cnidarians?
external fertilization with zygotes becoming planula larvae
WHat is the Poruguese man-of-war?
tentacles contain polyps with stinging nematocycsts
paralyze small prey; cause immense pain to humans, often accompanied by allergic reactions that lead to fever, shock and heart and lung problems
What is a Box Jellyfish?
Cubozoan class of Cnidaria
Deadly venom containing toxins that attack the heart, nervous system and skin cells
possess well-developed eyes.
What are Anthozoans?
marine, sessile (fixed position), polyp morphology, mostly in colonies
WHat are Anemones?
type of anthozoan
larger= solitary
smaller use asexual reproduction and live in large concentrations
disc-shaped bottom to attach to rocks
What are Hard Corals?
colonial; stony or reef building corals that form a skeleton made of calcium carbonate under the polyps to create the hard structure
What are Soft Corals?
Colonial; do not build a hard, calcium-carbonate skeleton. Instead create internal structural supports of fibrous proteins that allow them to grow vertically but still sway with ocean currents
What are zooxanthellae and dinoflagellates?
photosynthetic organelles that are found in tentacles providing energy to many hard corals
What are Ctenophora?
comb jellies
marine, radial symmetry
food capture using tentacles, locomotion via ciliated comb plates
bioluminescent
Why do Ctenophores look like jellyfish but aren’t part of the same phylum?
they lack stinging cells
What are Placozoans?
only 4 known species, flat organisms commonly less than 4mm in diameter, marine and feed on algae
How do Placozoans feed and move?
glide of surfaces grazing upon algae, which is digested externally
no neurons present, but use peptides for cell communication in a manner resembling the way animals with neuropeptides
What are Lophotrochozoa?
clade of 17 phyla - small marine animals
either have a tentacle line organ for filter feeding - lophophore
or a larva called trochophore
What are Platyhelminthes? (Flatworms)
Acoelomates
Ciliated epidermis (if present(
digestive system with one opening (if present)
circular and longitudinal muscle fibers
mostly hermaphroditic
What is the respiratory system in Flatworms like?
small size or thin bodies allows for gas exchange with environment by diffusion
some respiratory structures in larger animals
What is excretory system in Flatworms?
network of excretory tubules adjacent to flagellated flame bulbs or protonephridia
What is sexual reproduction in flatworms?
hermaphrodites exhibit cross-fertilization
penis is modified as a hollow stylet, with sperm transfer via hypodermic impregnation (turbellarians)
WHat are turbellarians?
freeliving animals marine and freshwater
carnivorous predators or detrivores
WHat are parasitic flatworms?
Trematodes, or Cestodes
What are Trematodes?
parasitize vertebrates as adults and mostly mollusks during larval stages
external or in digestive tracts or organs
What are Cestodes?
tapeworms - live in digestive tract
no digestive tract themselves have a scolex and proglottids
