Invertebrates- Cnidarians Flashcards

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1
Q

phylum

A

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

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2
Q

cnidocytes

A

stinging cells

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3
Q

form and function in cnidarians

A

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

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4
Q

body plan

A

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

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5
Q

feeding

A

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.

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6
Q

polyp

A

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

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7
Q

medusa

A

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

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8
Q

digestion

A

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.

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9
Q

respiration, circulation and excretion

A

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

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10
Q

response

A

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.

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11
Q

movement

A
  • 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.
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12
Q

reproduction

A

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.

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13
Q

groups of cnidarians

A

jellyfish, hydras and relatives, sea anemone and corals

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14
Q
  1. jellyfishes
A

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

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15
Q
  1. hydras and relatives
A

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)

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16
Q
  1. Sea anemone and corals
A
class Anthozoa (flower animal)
central body surrounded by tentacles (can)
17
Q

fresh water hydrozoans

A
are hydras they lack medusa stage
solidary polyp life history
asexual reproduction via budding
sexual reproduction - gametes produced in body wall
predatory animal
18
Q

corals

A

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

19
Q

sea anemone

A

sea anemones are individual polyps

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

20
Q

ecology of corals

A

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

21
Q

corals have

A

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

22
Q

human impact on corals

A

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

23
Q

nematocyst

A

poison filled stinging structure

24
Q

mesoglea

A

layer between epidermis and gastroderm

25
Q

sessile

A

immobile

26
Q

jet propulsion

A

mode of locomotion for medusa

27
Q

tentacle

A

long flexible appendage

28
Q

Portuguese matanowar

A

colonial hydra

29
Q

cnidocytes

A

stinging cells

30
Q

epidermis

A

outer layer of cells

31
Q

radical symmetry

A

body plan with equal halves when bisected through the centre

32
Q

hydra static skeleton

A

circular and longitudinal muscles along with water to facilitate movement

33
Q

statocyst

A

cells for detecting gravity

34
Q

ocelli

A

eyespots

35
Q

motile

A

can move around free living

36
Q

sedentary

A

can move bur remains in one spot often