Invertebrates- Cnidarians

Question 1

phylum

Answer 1

cnidarians, soft bodied, carnivores, symmetry, tentacles, speculated tissue, cnidocytes (stinging cells)

Question 2

cnidocytes

Answer 2

stinging cells

Question 3

form and function in cnidarians

Answer 3

most are only a few thick cells. simple body plan systems, primarily for feeding and movement

Question 4

body plan

Answer 4

radical symmetry, central mouth surrounded by numerous tentacles. 2 different stages, 1. polyp, 2. medusa.

Question 5

feeding

Answer 5

paralyzed prey pulled into gastrovascular cavity. digestion begins extracellularly- takes place outside of cells. partially digested food is absorbed by gastroderm. digestion completed intracellularly. undigested food passed out through mouth.

Question 6

polyp

Answer 6

cylindrical body plan, arm-like tentacles, mouth pointed upwards, usually sessile (stays in one spot)

Question 7

medusa

Answer 7

bell-shaped body plan, motile (free floating), mouth on downwards.

Question 8

digestion

Answer 8

takes place in gastrovascular cavity. a single opening cavity. gastroderm- inner lining of gastrovascular cavity. epidermis- over layer of cells. mesoglea- layer that lies between gastrovascular cavity and epidermis. may be non-cellular membrane or jelly-like material that contains cells.

Question 9

respiration, circulation and excretion

Answer 9

digested nutrients transported throughout body by diffusion, respiration and waste elimination is by diffusion through body walls.

Question 10

response

Answer 10

specialized sensory cells, cnidarians have nerve net, a loosely organized network or nerve cells, usually distributed uniformly throughout bod although some species have cent-ration of nerve cells around mouth or in rings around body. some cnidarians have statocysts- cells that detect gravity. have ocelli - eyespots that detect light.

Question 11

movement

Answer 11

• sea anemones have hydrostatic Skelton
• layer of circular muscles and layer of longitudinal muscles that work with water in gastrovascular cavity facilitate movement –> sea anemone can elongate or shorten. medusas can move through water via jet propulsion by opening and closing bell.

Question 12

reproduction

Answer 12

both sexual and asexual reproduction, polyps reproduce asexually by budding. most cnidarians, sexual reproduce takes place with external fertilization outside female’s body. eggs are fertilized –> free swimming larva develops –> becomes polyp and attached onto hard surface –> release medusa.

Question 13

groups of cnidarians

Answer 13

jellyfish, hydras and relatives, sea anemone and corals

Question 14

1. jellyfishes

Answer 14

class Scyphozoa (cup animals)
medusa primary life stage
small larva form as polyp
sexual reproduction

Question 15

2. hydras and relatives

Answer 15

class Hydrozoa
polyps grow into large branching colonies
polyps specialized to perform different functions
some develop float
others develop tentacles
some digest food
some produce, reproduce (gametes)

Question 16

3. Sea anemone and corals

Answer 16

class Anthozoa (flower animal)
central body surrounded by tentacles (can)

Question 17

fresh water hydrozoans

Answer 17

are hydras they lack medusa stage
solidary polyp life history
asexual reproduction via budding
sexual reproduction - gametes produced in body wall
predatory animal

Question 18

corals

Answer 18

corals are colonial
slow growth
colonies can be several hundreds of years old
some coral reproduce asexually by budding

Question 19

sea anemone

Answer 19

sea anemones are individual polyps

sexual reproduction as gametes are released into water for fertilization –> larva –> polyp.

Question 20

ecology of corals

Answer 20

colonies of corals –> coral reef, distribution determined by (temperature), (depth (water), (light intensity)

Question 21

corals have

Answer 21

mutuality relationships with photosynthetic algae
algae also help coral lay down calcium carbonate skeletons
corals can live in nutrient poor waters

Question 22

human impact on corals

Answer 22

a. damage by divers (remove coral)
b. silt and sediment damage from logging, farming, mining and construction
c. chemical poisoning from insecticides and industrial polluntants
d. over fishing upset ecological balance of fish
e. coral bleaching –> high temperatures kill algae –> white skeleton with transparent cells

Question 23

nematocyst

Answer 23

poison filled stinging structure

Question 24

mesoglea

Answer 24

layer between epidermis and gastroderm

Question 25

sessile

Answer 25

immobile

Question 26

jet propulsion

Answer 26

mode of locomotion for medusa

Question 27

tentacle

Answer 27

long flexible appendage

Question 28

Portuguese matanowar

Answer 28

colonial hydra

Question 29

cnidocytes

Answer 29

stinging cells

Question 30

epidermis

Answer 30

outer layer of cells

Question 31

radical symmetry

Answer 31

body plan with equal halves when bisected through the centre

Question 32

hydra static skeleton

Answer 32

circular and longitudinal muscles along with water to facilitate movement

Question 33

statocyst

Answer 33

cells for detecting gravity

Question 34

ocelli

Answer 34

eyespots

Question 35

motile

Answer 35

can move around free living

Question 36

sedentary

Answer 36

can move bur remains in one spot often