porifera and cnidaria Flashcards

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1
Q

what group are the phylum porifera in?

A

the basil group (earlier lineage to break away from the common ancestor)

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2
Q

what animal does the phylum porifera refer to?

A

sponges!

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3
Q

what are some characteristics of sponges?

A
  1. they have pores
  2. most abundant animal in the ocean
  3. most are sessile (do not move around), only the larvae move
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4
Q

what is the morphology of a sponge?

A
  1. no tissues or organs (no gut, muscles, nerves)
  2. some cells have specialized functions
  3. spicules (their version of a skeleton) give them structural support
  4. some sponges have only tough collagen-protein network for support
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5
Q

why are sponges considered to not have tissue even though some cells have a specialized function?

A

their ‘tissue’ is just a collection of cells, there is no separation from a membrane

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6
Q

in sponges, water gets pumped into _________ and it traps food

A

coenocytes

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7
Q

what are the two cells of the porifera?

A

choanocyte and mesophyll

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8
Q

what feeding process do sponges undergo?

A

filter feeding - suspension feeding

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9
Q

at the base of the choanocyte, food particles are engulfed by?

A

phagocytosis!

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10
Q

what is the function of the amoebocytes in filter feeding?

A

amoebocytes are fixed, and can move throughout the mesophyll taking food wherever is needed

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11
Q

what are some reproductive qualities of sponges?

A
  1. most sponges are hermaphroditic (possess male and female organs)
  2. sequential - can be simultaneously male and female, or switch from male to female
  3. they do not have ovaries or testes
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12
Q

how do egg cells arise in sponges?

A

from modified amoebocytes

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13
Q

how do sperm cells arise in sponges?

A

from modified choanocytes

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14
Q

do they use external or internal fertilization?

A

mostly internal

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15
Q

how do sponges reproduce?

A
  1. release of flagellated modified choanocyte (sperm)
  2. fertilizes amoebocytes in the mesophyll
  3. becomes a free-swimming larva
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16
Q

adult sponges are sessile, except for which stage?

A

ciliated larval stage

17
Q

why are sponges important?

A
  1. they are filter feeders that clean the water
  2. many sponges have symbiotic relationships with single-celled algae and other organisms - mutualistic
18
Q

what are some characteristics of animals in the phylum cnidaria?

A
  1. eumetazoa - true, differentiated tissues
  2. most have radial symmetry
  3. diploblastic - endoderm and ectoderm
  4. organs - collection of tissues specialized for different tasks
19
Q

what animals does the phylum cnidaria encompass?

A

jellyfish, hydra, sea anemones, coral

20
Q

what are the twos forms of cnidaria?

A

medusa and polyp

21
Q

what are some characteristic of the medusa?

A

motile form
oral end downwards (mouth/anus)
moves freely through water through the hydrostatic skeleton (compressed muscles against cavity provides mobility)
have tentacles

22
Q

what are some characteristics of the polyp?

A

sedentary (sessile)
oral end upwards (mouth/anus)
attached to a substrate (rock, coral)
have tentacles

23
Q

the polyp and medusa body forms have a gastrovascular cavity, not a?

A

coelom!

24
Q

are cnidarians omnivores, carnivores or herbivores?

A

carnivores

25
Q

cnidarians have specialized cells called?

A

cnidocyte

26
Q

what is the function of the cnidocyte?

A

a specialized cell for capturing prey

27
Q

each cnidocyte contains?

A

a very complex endocellular structure

28
Q

what is the most common type of endocellular structure?

A

nematocyst

29
Q

how do cnidarian and cnidocytes capture prey?

A
  1. trigger spine of cnidocyte is touch-sensitive
  2. nematocyst shoots out
  3. others may be sticky, stabbing or poison tipped
  4. the prey is digested in the gastrovascular cavity
  5. nutrients is absorbed by nearby cells
30
Q

what are reefs constructed by?

A

corals that provide shelter and food for many marine species

31
Q

what are zooplankton?

A

tiny animals drifting in the water

32
Q

what is the life cycle of hydrozoan obelia?

A
  1. polyp (feeding stage) turns into reproductive stage (medusa)
  2. medusa buds off and sometimes forms a motile medusa stage
  3. within the medusa there are gonads that make gametes through meiosis
  4. produce egg and sperm, fertilized, becomes a zygote and then larva
  5. once larva settles down somewhere, it returns to the polyp stage
    (NOTE: not all form medusa)