phyla cnidaria + ctenophora

cnidaria and ctenophora can be described as ___ animals

radiate

radiate animals can have these 2 types of symmetry

radial, biradial

cnidarians and ctenophores are ___blastic

diplo

shape of animals with biradial symmetry

football

instead of head/tail or dorsal/ventral, radiate animals use an __/___ axis

oral/aboral

radiate animals’ organization level

cell-tissue

instead of a central nervous system, radiate animals have a…

nerve net

2 sensory organs in radiate animals

ocelli, statocysts

ocelli function

detect light and dark

statocyst function

senses orientation in space

what are the germ layers present in radiate animals?

epidermis, gastrodermis, mesoglea

gastrodermis lines radiate animals from their ___ to ___ ___

mouth, gastrovascular cavity

food enters and exits through the ___ in radiate animals

mouth

starting with statocyst, what is the basic pathway stimuli “takes” to cause movement?

statocyst, nerve, muscle

conserved definition

lasted through evolution

the sodium-potassium nerve system is the same in all animals, so it can be described as…

conserved

there are more than ___ species in phylum cnidaria

9000

all cnidarians are ___, and most live in ___ environments

aquatic, marine

the cnidarian fossil record goes back about ___ ____ years

700 million

what cells are unique to cnidarians?

cnidocytes

what do cnidocytes do and how?

sting by shooting out nematocyst

do cnidarian nerves decide to sting?

yes

can a single nematocyst be fired out multiple times?

no

cnidocytes need to ____ after each use

regenerate

2 basic body forms of cnidarians

polyp, medusa

since cnidarians can have 2 different body forms during their lifetime, they can be described as…

dimorphic

what is a planula?

ciliated cnidarian larva

the planula is a _____ between all cnidarians

synapomorphy

how many tissue layers does a planula have?

2

do planula have a mouth or gut?

no

what happens after a planula runs out of energy?

settles to floor, becomes polyp

what type of reproduction do medusae carry out?

sexual

what type of reproduction do polyps carry out?

asexual

after medusae reproduce, the offspring get… (location-wise)

dispersed

after polyps reproduce, where do the offspring end up? (location-wise)

next to parent

many polyps in one area leads to more ____ between organisms

competition

another term for cnidarian polyps

hydroids

polyps are mostly ____/sedentary

sessile

cnidarian mouths are used for these 2 processes

ingestion, egestion

egestion

getting rid of undigested food waste

what attaches polyps to substrate?

pedal disc

3 ways polyps can reproduce asexually

budding, pedal laceration, fission

another term for polyp budding

strobilation

medusae are ___ecious

dio

medusa tentacles extend down from the __ of their bell

rim

what structures hang around medusae’s mouths?

oral arms

how do medusae move?

contracting bell

how do polyps move?

gliding on pedal disc

what aids pedal disc movement?

mucus

all cnidarians can move their…

tentacles

what do cnidarians have instead of mesoderm-derived muscles?

epitheliomuscular cells

epitheliomuscular cells make up most of this tissue in cnidarians

epidermis

the epitheliomuscular tissue is linked to what other structure?

nerve net

only muscles and nerves that are ___ to each other can work together

close

decisions are made by nerves as ____ progresses

stimuli

the system in which nerves and muscles respond to stimuli can be called a…

behavior cascade

nematocyst structure description

capsule containing coiled filament

nematocysts often have 1 of these 3 things that can hurt threats/prey

barbs, spines, toxins

what is the trigger on nematocysts?

cnidocils

cnidocils are modified ___

cilia

how fast can nematocysts be discharged?

2 meters/second

what is the most dangerous type of jellyfish, especially in australia?

box jellyfish

5 classes within phylum cnidaria

hydrozoa, scyphozoa, anthozoa, cubozoa, staurozoa

anthozoa always have this body form

polyp

3 example organisms for class anthozoa

anemones, sea fans, corals

class staurozoa description

small polyps, like to hang out on kelp

example organism for class cubozoa

box jellyfish

the ___ stage of cubozoa has never been seen

polyp

class scyphozoa description

true jellyfish, mostly medusa

which cnidarian class is most diverse?

hydrozoa

_____ are commonly colonial

hydrozoans

2 ways that hydrozoan medusae are different from scyphozoan medusae

closed-off bell, manubrium instead of oral arms

anthozoans can have hexamerous or octomerous radial symmetry based on the arrangement of their ___ and ___

septa, tentacles

what does anthozoa mean?

flower animals

what structures divide anthozoan gastrovascular canals?

septa

____ ___ are among the most productive and threatened ecosystems on earth

coral reefs

another term for organisms in class staurozoa

stauromedusans

do organisms in class staurozoa have a medusa stage?

no

can stauromedusans reproduce both sexually and asexually?

yes

stauromedusans’ polyp top looks like a ____ with 8 tentacled arms

medusa

where do box jellyfish tentacles hang from?

corners of box

ability unique to box jellyfish ocelli

image forming

for efficient swimming, box jellyfish can turn their bell inward to form a ____

velarium

a box jellyfish velarium shoots out water and results in ____ movements

jerky

some box jellyfish species have ____ that are deadly to humans

toxins

scyphozoans have a thick layer of…

mesoglea

how many oral arms do scyphozoans have?

4

scyphozoan reproduction (4 steps)

medusae reproduce sexually to form zygote, planula develops and settles into polyp, forms strobila, develops back into medusa

reproduction in hydrozoan polyps

gonangium asexually produces medusa buds

reproduction in hydrozoan medusae

sexual reproduction makes polyps

hydra are atypical in these 2 ways (environment, body forms)

freshwater, only polyps

what is one structure unique to hydrozoans?

perisarc

what is perisarc?

protective chitinous sheath

hydranth function and appearance

feeding, looks like anemone

gonangium function and appearance

asexual reproduction, looks like stalk filled with discs

example of a paedomorphism in hydrozoan medusae

mouth at end of manubrium

portuguese man o’war is made up of a colony of ____ attached to a _____ (body forms)

polyps, medusa

how many species of ctenophores are there?

150

what does “ctenophora” mean?

comb-bearing

all ctenophora live in ___ environments

marine