Cnidaria/Ctenophora Flashcards

0
Q

What are the two tissue types of cnidarians?

A

Gastrodermis and epidermis.

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1
Q

What are the main taxonomic features of phylum cnidaria?

A

They possess a cell called cnidocytes, which contain an organelle called a cnidocyst (e.g. a nematocyst). They come in various forms; can inject poison or attach to the prey. They have a high taxonomical importance. They’re used to capture prey or for defence.

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2
Q

What are the two body forms of cnidarians?

A

Polyps and medusa.

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3
Q

What is the gastrovascular cavity?

A

The blind-sac gut.

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4
Q

What is the mesoglea?

A

A gelatinous protein layer between the epidermis and the gastrodermis.

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5
Q

What kind of body plan do all cnidarians have?

A

A radially symmetrical body plan.

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6
Q

What is a nerve net?

A

A diffuse mesh of nerve cells that take part in simple reflex pathways. Nerve cells interact with sensory and contractile cells. Epitheliomuscular cells work in coordination with the nerve net. There is no brain/CNS.

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7
Q

What are statocysts?

A

Cells that are able to sense gravity.

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8
Q

What are the four classes within the phylum cnidaria?

A

Hydrozoa, Scyphozoa, [Cubozoa], Anthozoa.

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9
Q

What is contained within the class Hydrozoa?

A

Portuguese man o’ war, hydra, and other medusas.

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10
Q

What is contained within the class Scyphozoa?

A

Includes the true jellyfish.
Stauromedusae - stalk jellyfish.
Coronatae - deep sea primarily.
Semaeostomeae - common and moon jellyfish, lion’s mane.
Rhizostomae - barrel jellyfish (big, solid, can be eaten).

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11
Q

What is contained within the class Cubozoa?

A

The cubomedusae, the box jellyfish and sea wasps [incredibly toxic and dangerous to humans].

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12
Q

What is within the class Anthozoa?

A

Corals, sea fans and sea pens.
Ceriantipatharia
Alcyonaria=octocorallia [octocorals]
Zoantharia=Hexacorallia. [Anemones and true corals].

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13
Q

What are the two subphyla?

A

Medusozoa and Anthozoa - not often used apart from true jellyfish nerds.

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14
Q

What are the general features of class Hydrozoa?

A

The medusa have a velum ‘skirt’ and nerve ring. The asexual polypoid body form is the dominant part of the life cycle with specified buds for reproducing/feeding. Reproductive buds tend not to have tentacles. There are thousands of species.

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15
Q

What is the life cycle of Hydrozoa?

A

Sexually reproducing medusa produce eggs & sperm.
A fertilised egg becomes a non-feeding (lecithotrophic) planula.
This then becomes a young polyp colony, which is the asexual part of the life cycle.
This polyp produces new medusa through budding.

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16
Q

What do the hydromedusae often do?

A

Be fluorescent? They can also have a protruding mouthpart resembling a tentacle.

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17
Q

What are the hydrocorals?

A

They are hydroids that form hard skeletons, for example Millepora the fire coral.

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18
Q

In class Hydrozoa, what are siphonophores?

A

Siphonophores are gelatinous, fragile, colonial organisms. They are made up of specialised individuals. They lack a benthic phase. There are three groups and the organisation of the colony defines which group.

19
Q

What are the types of individual polyps found in siphonophores?

A

They all start with a pneumatophore which is a gas filled float. They may also have nectophores (swimmming structures), siphosomal growth zones, gastrozooids, gonozooids, and dacctylzooids (for defence).

20
Q

What are the three groups of siphonophores?

A

Physonects
Cystonects (no nectophores)
Calycophorans (no nematophores)

21
Q

What is a Portuguese man o’ war and a by the wind sailor?

A

A siphonophore with a large pneumatophore and very specialised polyps.
A siphonophore that lives at the boundary between sea and air - a neuston.

22
Q

What are the defining features of class Cubozoa?

A

They have a cuboid shape and the margin of the bell is NOT scalloped.
They have a velarium (a flap of tissue on the underside of the bell)
Rhopalium has complex eyes with lenses.
They are VERY poisonous.

23
Q

What are the two types of Cubozoa and what are their defining characteristics?

A

Carybdeids - one tentacle per pedalium (corner)

Chirodropids - multiple tentacles per pedalium.

24
Q

What is the binomial name of the box jelly and irukandji jelly?

A

Box - Chironex fleckeri
Irukandji - Caruka barnesi
+smaller
+not as deadly but DEF painful.

25
Q

What is the life cycle of Cubozoa?

A

A sexually reproducing adult produces planulae. These go through asexual reproduction and then carry out metamorphosis of a fully-grown polyp into a single medusa.

26
Q

What are the defining characteristics of class Scyphozoa?

A

Similar to Hydrozoa but:
Medusa form is dominant (with polyp sometimes absent).
Manubrium is tentaculate
There is no velum.
The mesoglea is thick and contains amoebocytes.
Gonads are gastrodermal.
There are 3 orders and approx 200 spp

27
Q

What is the life cycle of an individual in class Scyphozoa?

A

‘Ripe’ medusa produce planula larvae through sexual reproduction. This forms a scyphistoma (polyp), which goes through asexual reproduction. A single polyp can live for 3-5 years and produce dozens of new ‘ephyra’ which become developing medusa which become ripe medusa.

28
Q

Within class scyphozoa, what are the features of order Semeaeostomae?

A

Four long frilly arms, bell margin scallowed, and large, mainly coastal species.
Include Aurelia aurita (moon or common jelly), Cyanea capillata (lions mane and one of the largest organisms extant)

29
Q

Within class scyphozoa, what are the features of order Rhizostomeae?

A

Thick mesoglea
Polyps reproduce via podocysts (become a new polyp but produces less jellies)
No tentacles on the bell margin
Large oral arms.
Include upside down jellyfish, cannonball jellyfish and fried egg jelly.

30
Q

Within class scyphozoa, what are the features of order Coronatae?

A

They have a characteristic ‘coronal groove’.
They are deep sea, usually red and bioluminescent.
Egg develops directly into medusa - polyp impractical.

31
Q

What are the defining features of class Staurozoa?

A

They are the stalked jellyfish or stauromedusae.
Typically 1-4cm & attached to weed, rocks or gravel.
NO swimming adult medusa.

32
Q

What are the general features of class Anthozoa?

A

Flower animals with 3 subclasses:
+Hexacorallia (or Zoantharia) = 6 part (or 8 or 10) symmetry. Sea anemones, true corals, zoanthids.
+Octocorallia (or Alcyonaria) = 8 part symmetry. Sea pens, gorgonian sea fans and sea whips.
+Ceriantipatharia = tube anemones (cerianthids), black corals.
Possess POLYP only.
All three types of cnidae - nematocysts, spirocysts (sticky), ptychocysts (for gripping seabed).
>6000 spp from intertidal to deep sea (~6000m)

33
Q

What is the basic body plan of an anthozoa?

A

The gastrovascular cavity or coelenteron is extensively subdivided by mesenteries (infoldings of the mesoglea and endoderm). Tentacles are hollow extensions of the coelenteron. The pedal disk attaches it to the seafloor and the

34
Q

What are the characteristics of subclass Ceriantipatharia?

A

They live in soft sediments and have a tube made of ptychocysts and mucous, woven together. They are most easily recognisable by said tube.

35
Q

What are the characteristics of subclass Hexacorallia - Order Actiniaria?

A

True sea anemones. They are solitary or clonal but not colonial. Some have a chitinous cuticle & some have zooxanthellae. ~800 spp in 41 families. Largest family = Actiniidae

36
Q

What are the characteristics of subclass Hexacorallia - Order Zoanthidea?

A

Sometimes called Order Zoantharia. Colonial - polyps arise from basal mat. They incorporate sand, debris into the body wall. Many zooxanthellate - live in shallow light environments.
Many are epizoic. Mainly tropical/subtropical and deep sea.

37
Q

What are the characteristics of subclass Hexacorallia - Order Scleractinia?

A

They are the hard or stony corals. They can be solitary or colonial. They are dependent on zooxanthellae for calcification and healthy growth. There can be huge morphological diversity - many different types. A diversity of 29 families.

38
Q

What are the characteristics of subclass Octocorallia?

A

The classification of order and suborder is in flux.
They include soft corals, sea fans/whips, sea pens/pansies & blue corals.
Their common characteristics are 8 hollow, marginal pinnate tentacles, 8 complete mesenteries and interconnected gastrovascular canals.

39
Q

What are the characteristics of subclass Octocorallia - order Alcyonacea?

A

They are soft corals, appear fleshy - contain minute, spiny skeletal sclerites. Small to massive colonial forms.

40
Q

What are the characteristics of subclass Octocorallia - order Gorgonacea?

A

Sea fans and sea whips.
Firm internal skeleton made of protenaceous gorgonin.
Diverse group with 18 families. Tropical to deep sea.

41
Q

What are the characteristics of subclass Octocorallia - order Pennatulacea?

A

Sea pens and pansies. Complex, polymorphic colonies. Live in soft sediments. Elongated primary axial polyp.

42
Q

What are the taxonomic features of Phylum Cenatophora?

A

Biradial symmetry around the oral-aboral axis.
Sticky colloblasts - no stinging cells.
8 rows of ciliary plates (combs or ctenes) for swimming.
Diploblastic (or triploblastic??)
Monomorphic, without alteration of generations.
Most hermaphroditic, with cydippid larval stage.
Paired tentacles present at some point in life history.

43
Q

What are the main classes and orders of ctenophores?

A
Class NUDA (without tentacles)
\+Order Beroida
Class TENTACULATA (with tentacles)
\+Order Cydippida
\+Order Lobata
\+Order Cestida
44
Q

What are the main characteristics of Class Nuda?

A

They look like slugs tbh. One order (Beroida), one family (Beroidea), 2 genera (Beroe, Neis). I guess they just suck stuff in like a vacuum. They look a lot like shiny slugs. They eat other ctenophores so

45
Q

What are the main characteristics of class Tentaculata?

A

They have tentacles and look less like slugs. Some are invasive species. They are deep sea or not. They kind of just wiggle through the water column idk it’s 1am fuck off