Cnidaria

Question 1

Name the 8 traits of the phylum Cnidaria

Answer 1

1. Diploblasty - 2 distinctive germ layers: ectoderm and endoderm
2. Incomplete gut - only one hole. Has a GVC
3. Epitheliomuscular cell - allows cnidarians to move. Not really muscles, but they’re like skin cells and are contractile
4. Radial symmetry
5. Net-like nervous system
6. Cnidae
7. Polpys - body plans. The medusa states are only found in medusazoa
8. Circulation - GVC. They exchange gas by diffusion

Question 2

3 synapomorphies of Cnidaria

Answer 2

1. Epitheliomuscular cell
2. Cnidae
3. Polyps

Question 3

Cnidae

Answer 3

Located inside a structure called cnidocyte. The nematocyst will fire a harpoon in the organism

Question 4

Nematocysts

Answer 4

Located inside the cnidocyte cells on the tentacles. It penetrates the prey and releases toxins

Question 5

Spirocysts

Answer 5

Sticking spaghetti noodles to entangle the prey. Specializes in animals with exoskeletons

Question 6

Cnidaria major subgroups

Answer 6

Anthozoa - sea anemones, like corals

Medusazoa - can move and swim. Hydrozoa and Scyphozoa belong to this group

Question 7

2 taxa of Medusazoa

Answer 7

Hydrozoa - hydroids, hydras. Prominent polyp stage where some are solitary and some are colonial. The polyp stage gives rise to an asexually produced medusa stage called the hydromedusa, which reproduces sexually. Has a mesoglea

Scyphozoa - considered the “true” jellyfish and has a prominent medusa stage. Has a mesenchyme

Question 8

Enzymatic gland cells

Answer 8

Releases proteins/enzymes in the GVC to breakdown food

Question 9

Mucus gland cell

Answer 9

Added layer of protection on epidermal cells

Question 10

Operculum

Answer 10

The lid of the cnidocyte

Question 11

Cnidocil

Answer 11

The trigger of the cnidocyte. When something brushes against it, it triggers the cnidocyte and shoots out the nematocyst

Question 12

Hydra

Answer 12

Genus of hydrozoans. Solitary polyp freshwater. Experiments have been done to hydras that show that they have the ability to re-fashion its cells as adults. It can turn its epidermis to the gastrodermis and vice versa

Question 13

Gonad in Hydra

Answer 13

Ectodermally derived in Hydra

Question 14

Obelia

Answer 14

Genus of hydrozoans. Hydroids are examples. They are colonial and marine. They look like flower bouquets

Question 15

Gastrozooid

Answer 15

Subcomponent of the obelia colony. Focused on feeding

Question 16

Gonophore

Answer 16

A structure that will develop into a medusa

Question 17

Gonozooid

Answer 17

For reproduction to build and bud Medusa

Question 18

Perisarc

Answer 18

Made of chitin. Surrounds the whole colony of obelia

Question 19

Dactylozooid

Answer 19

Used for defense. Extra long. Usually filled with nematocyst

Question 20

Coenosarc

Answer 20

Hollow fluid-filled space that surrounds the colony that connects the zooids of a hydroid colony

Question 21

Physalia

Answer 21

Genus of hydrozoans. Are considered the floating colony. An example is siphonophora

Question 22

Pneumatophore

Answer 22

Covered in perisarc. A gas-filled float that helps Physalia float

Question 23

Clonal

Answer 23

Genetically identical. Not integrated at the tissue level. Physically separated

Question 24

Colonial

Answer 24

Genetically identical and connected at the tissue level

Question 25

Acrorhagi

Answer 25

Located around the collar of an anemone. Filled with nematocysts to defend

Question 26

Collar

Answer 26

Can close the opening of the anemone to protect itself. Tentacles retract

Question 27

Bump

Answer 27

Sticks to shell fragments/sand to protect itself when tide is low. Can also protect itself from other animals

Question 28

Hole

Answer 28

Where water can enter/exit

Question 29

Limbus

Answer 29

Area of the anemone that gets cut off during pedal laceration

Question 30

Sclerites

Answer 30

CaCO3 located inside animals and protects them

Question 31

Corallite

Answer 31

CaCO3 house of 1 polyp

Question 32

Corallum

Answer 32

Fusion of many corallite to make one big structure. Each corallite builds their own CaCO3 house

Question 33

Siphonoglyph

Answer 33

Pushes water in the GVC of an anemone

Question 34

Gonad in an Anemone

Answer 34

Can be testes or ovaries. Endodermally derived. The gonad is protected in the GVC. Allows them to not have to eat/produce gametes at the same time

Question 35

Retractor band of epitheliomuscle cell

Answer 35

Makes the anemone short/fat

Question 36

Radial band of epitheliomuscle cell

Answer 36

When contracted, trunk of Anemone gets short/long

Question 37

Acontia

Answer 37

Branches off mesenteries. Catches and paralyses food. Loaded with nematocysts

Question 38

Pharynx

Answer 38

Has ciliated grooves that push water

Question 39

Incomplete septum (mesentary)

Answer 39

Increases surface area for extracting nutrients

Question 40

Complete septum (mesentary)

Answer 40

Connects outside body wall to pharynx. Provides structural support

Question 41

3 types of asexual reproduction

Answer 41

1. Budding 2. Fission - splitting one thing into 2 3. Pedal laceration - the cutting of the pedal disc that gives rise to a new organism

Question 42

Sexual reproduction

Answer 42

View notes for cycle

Question 43

Plankotrophic

Answer 43

In the absence of medusa, the Anthozoa uses a larval stage to distribute and move

Question 44

Lecithotrophic

Answer 44

Larval stage of Hydrozoa and Scyphozoa. Since they have a medusa stage that allows them to swim around, they can survive with yolk

Question 45

Hydromedusae

Answer 45

Have a tall and small bell

Question 46

Velum

Answer 46

Thin membrane that controls the size of the opening into the subumbrella space. Can contract or open to control the opening of the hole and assist in movement by jet propulsion

Question 47

Gonads in Hydromedusae

Answer 47

Derived from ectoderm. Can be testes or ovaries. They look long and wormy

Question 48

Manubrium

Answer 48

Cylinder of tissue holding the GVC opening. Bears the mouth at the tip. Tentacles bring food to this area to feed

Question 49

Subumbrellar space

Answer 49

Concave undersurface. Also aids in movement since it works with jet propulsion and the vellum

Question 50

Tentacular bulb

Answer 50

Sensory tissue at the base of the tentacle. It's a concentration of receptors

Question 51

Scyphomedusae

Answer 51

Shallow bell

Question 52

Gonads in Scyphomedusae

Answer 52

Endodermally derived. Something about shutting down so they don't eat the gonad?

Question 53

Oral arm of Scyphomedusae

Answer 53

An extension of the manubrium and captures prey and moves it into the mouth.

Question 54

Subgenital pit

Answer 54

Escape routes for gametes

Question 55

Branched radial canals

Answer 55

Distinct feature of the Scyphozoa

Question 56

Septum (also called the mesentery)

Answer 56

Divides the cavity of the Scyphomedusae

Question 57

Sensory organs of the Cnidaria

Answer 57

Tactile - sense of touch Chemoreceptors - ability to sense chemicals, such as taste and smell Photoreceptors - sense intensity of light Georeceptors - senses earth's gravitational field

Question 58

Statocyst

Answer 58

Associated with georeceptors. They're fluid-filled organs that have highly sensitive cilia that sent signals to the brain when a rock-like thing hits the cilia. It helps with orientation and directionality

Question 59

Rhopalium (rhopalia, p.)

Answer 59

Small sensory structure found within Scyphozoa that consists of neurons that can be used to sense light. Located between a pair of lappets

Question 60

Gastrulation

Answer 60

Gut formation in Cnidaria

Question 61

Invagination

Answer 61

Pushes cells into blastocoel and the hole begins to form

Question 62

Blastopore

Answer 62

The opening to the forming gut

Question 63

Blastocoel

Answer 63

Hollow cavity