Sponges, Cnidarians, and Platyhelminthes

Question 1

What are sponges widely considered as?

Answer 1

basal animals - meaning it is sister to all other animals

Question 2

What are Choanoflagellates (in relation to animals)?

Answer 2

sister taxon of animals
ancestral to sponges

Question 3

What is the other phylum that could be basal over sponges?

Answer 3

Ctenophores

Question 4

What is the phylum name for sponges?

Answer 4

Porifera

Question 5

WHat makes Sponges animals?

Answer 5

similar embryonic development
simple immune system
ion channels to make neuron function
have homologous genes required to make neurons

Question 6

When did the first sponges appear?

Answer 6

some fossils up to 710mya
most appear just before Cambrian period 560mya

Question 7

What are choanocytes?

Answer 7

flagellated cells that set up currents that draw water into the cavity. and ingest and process food

Question 8

What is the mesohyl?

Answer 8

gel-like and supports cells that form spicules and generate feeding and reproductive cells

Question 9

What are skeletons in some sponges made of?

Answer 9

sipcules made of silica, calcium carbontae, or proteins
or spongin made of protein

Question 10

How do sponges gain nutrition?

Answer 10

intracellular digestion - the circulating water contains food particles and dissolved organic matter, with cells lining the cavity capture by endocytosis

Question 11

What is significant about reproduction in sponges?

Answer 11

no reproductive organs, but cells that migrate n to the mesohyl and differentiate as sperm or eggs
most are hermaphrodites

Question 12

Describe sexual reproduction in sponges

Answer 12

sperm is released and taken up by another individual; fertilized eggs develop into ciliated free-swimming larvae which eventually differentiates into an adult sponge

Question 13

How can sponges reproduce asexually?

Answer 13

fragmentation

Question 14

Describe Sponge diversity

Answer 14

15000+ identified species most marine around 150 freshwater
cover almost every part of ocean
75% of biomass on floor of Antarctic ocean

Question 15

What differentiates Sponges from Choanoflagellates?

Answer 15

multicellularity, gastrulation, collagen

Question 16

What differentiates Cnidarians from Sponges?

Answer 16

Tissues

Question 17

WHta differentiates Cnidarians and Bilaterians?

Answer 17

Cnidarians exhibit radial symmetry
Bilatarians exhibit Bilateral symmetry and complex organs

Question 18

What re distinct characteristics of Cnidarians

Answer 18

Radially symmetrical
2 tissue layers with non cellular jelly like material between

Question 19

What re the features of the tissue layers in Cnidarians?

Answer 19

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)

Question 20

What are the types of Cnidarian body plans?

Answer 20

Medusa form
Polyp form

Question 21

What is a Medusa form Body plan?

Answer 21

bell-shaped or umbrella shaped body, with the mouth directed downward

Question 22

What is a Polyp form body plan?

Answer 22

Tubular body with the mouth directed upward

Question 23

What is the nervous system in Cnidarians?

Answer 23

epidermis and endodermis possess nerve cells arranges in a loose network of intersecting nerves - nerve net (plexus)

Question 24

How do Cnidarians obtain food?

Answer 24

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

Question 25

What is a diagnostic characteristic of the phylum Cnidaria?

Answer 25

stinging organelles (enidocytes)

Question 26

WHat do stinging organelles of cnidarians do?

Answer 26

enhance prey capture
entangle prey or harpoon prey and inject a paralyzing toxin

Question 27

How does asexual reproduction work in Cnidarians?

Answer 27

budding or pedal laceration for sea anemones

Question 28

What is pedal laceration in sea anemones?

Answer 28

a new anemone is formed once a grown anemone moves away from an area, leaving behind some fragments of its pedal disc

Question 29

What are Hydrozoans?

Answer 29

Class of Cnidarians
sessile (permanently attached or established)
mostly marine
most live in colonies of polyps

Question 29

WHat are Scyphozoans?

Answer 29

class of Cnidaria
marne; free-swimming with prominent medusa (bell-shaped) morphology as adults

Question 29

What is sexual reproduction in Cnidarians?

Answer 29

external fertilization with zygotes becoming planula larvae

Question 30

WHat is the Poruguese man-of-war?

Answer 30

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

Question 31

What is a Box Jellyfish?

Answer 31

Cubozoan class of Cnidaria
Deadly venom containing toxins that attack the heart, nervous system and skin cells
possess well-developed eyes.

Question 32

What are Anthozoans?

Answer 32

marine, sessile (fixed position), polyp morphology, mostly in colonies

Question 33

WHat are Anemones?

Answer 33

type of anthozoan
larger= solitary
smaller use asexual reproduction and live in large concentrations
disc-shaped bottom to attach to rocks

Question 34

What are Hard Corals?

Answer 34

colonial; stony or reef building corals that form a skeleton made of calcium carbonate under the polyps to create the hard structure

Question 35

What are Soft Corals?

Answer 35

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

Question 36

What are zooxanthellae and dinoflagellates?

Answer 36

photosynthetic organelles that are found in tentacles providing energy to many hard corals

Question 37

What are Ctenophora?

Answer 37

comb jellies
marine, radial symmetry
food capture using tentacles, locomotion via ciliated comb plates
bioluminescent

Question 38

Why do Ctenophores look like jellyfish but aren’t part of the same phylum?

Answer 38

they lack stinging cells

Question 39

What are Placozoans?

Answer 39

only 4 known species, flat organisms commonly less than 4mm in diameter, marine and feed on algae

Question 40

How do Placozoans feed and move?

Answer 40

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

Question 41

What are Lophotrochozoa?

Answer 41

clade of 17 phyla - small marine animals
either have a tentacle line organ for filter feeding - lophophore
or a larva called trochophore

Question 42

What are Platyhelminthes? (Flatworms)

Answer 42

Acoelomates
Ciliated epidermis (if present(
digestive system with one opening (if present)
circular and longitudinal muscle fibers
mostly hermaphroditic

Question 43

What is the respiratory system in Flatworms like?

Answer 43

small size or thin bodies allows for gas exchange with environment by diffusion
some respiratory structures in larger animals

Question 44

What is excretory system in Flatworms?

Answer 44

network of excretory tubules adjacent to flagellated flame bulbs or protonephridia

Question 45

What is sexual reproduction in flatworms?

Answer 45

hermaphrodites exhibit cross-fertilization
penis is modified as a hollow stylet, with sperm transfer via hypodermic impregnation (turbellarians)

Question 46

WHat are turbellarians?

Answer 46

freeliving animals marine and freshwater
carnivorous predators or detrivores

Question 47

WHat are parasitic flatworms?

Answer 47

Trematodes, or Cestodes

Question 48

What are Trematodes?

Answer 48

parasitize vertebrates as adults and mostly mollusks during larval stages
external or in digestive tracts or organs

Question 49

What are Cestodes?

Answer 49

tapeworms - live in digestive tract
no digestive tract themselves have a scolex and proglottids