phylum Cnidaria
Characteristics
-More advanced or 'evolved' than sponges
-Classes:
-Hydrazoa
-Anthrozoa
-Scyphozoa
-Acoelomates
-Diploblastic (Ecto, Endo)
-Nerve net
-Radial Symmetry
-Polyps and Medusa stages (Polyp: filter-feeding)(Medusa: heterotrophic)
-'Sting' with cnidocytes
-Classes:
-Hydrazoa
-Anthrozoa
-Scyphozoa
-Acoelomates
-Diploblastic (Ecto, Endo)
-Nerve net
-Radial Symmetry
-Polyps and Medusa stages (Polyp: filter-feeding)(Medusa: heterotrophic)
-'Sting' with cnidocytes
Lab:
Results:
1. What type of life cycle do cnidarians display and what is the function of each 'generation' within the life cycle?
Alternation of Generations life cycle: polyp and medusa. Firse, a Cnidrian Polyp, non-motile, water filter-feeding, bell down tentacles up, preforms asexual reproduction and creates hundreds of medusa offspring. These medusa Cnidarians are motile and heterotrophic, they reproduce sexually by either growing sperm or eggs in their gonads and releacing them into the water. when a sperm meets an egg, a zygote forms, falls to the bottom of the body of water, and grows by mitosis into a polyp. the amount of time spent in each stage depends on what class of Cnidarian it is.
2. What is the difference between a cnidocyte and a nematocyst?
A cnidocyte is the stinging cell that is on the outside of a Cnidarian's tentacles that cause stinging. a nematocyst is a barb that is on the inside of the cnidocyte that shoots out and hooks on to the victim of the cnidarian's sting.
3. How does a nematocyst fire?
the barb on the outside of the cnidocyte touches something and is triggered, this opens the operculum, and the nematocyst fires out, injecting venom.
4. In Obelia, describe the role of each type of polyp and the medusa
Obelia is Polyp dominant, so it spends most of its life in the polyp stage. the role of the Obelia Poluyp is to determine whether or not the area it lives in is sutable for it's medusa offspring. if it determines that the environment is safe, it will reproduce medusa by budding and release them into the water. because the Obelia doesnt stay in the medusa stage for very long time before they reproduce and form polyps, the medusa's job is basically to spread the species.
5. How is the Portuguese Man-O-War similar and different to Hydra and Obelia?
The Man-O-War and the hydra and obelia have tentacles with cnidocytes, a large, non-stinging body, has one spot that acts as a mouth and anus, both belong to Cnidaria, . Only the Man-O-War is much larger, lives in salt water, and has a sting that can cause severe pain to humans. they are different because the Man-O-Wa belongs to class Scyphozoa, and Obelia and hydra belong to class Hydrozoa. this means the Man-O-War spends much more time as a medusa, and mush less time as a polyp than the Obelia and Hydra.
Alternation of Generations life cycle: polyp and medusa. Firse, a Cnidrian Polyp, non-motile, water filter-feeding, bell down tentacles up, preforms asexual reproduction and creates hundreds of medusa offspring. These medusa Cnidarians are motile and heterotrophic, they reproduce sexually by either growing sperm or eggs in their gonads and releacing them into the water. when a sperm meets an egg, a zygote forms, falls to the bottom of the body of water, and grows by mitosis into a polyp. the amount of time spent in each stage depends on what class of Cnidarian it is.
2. What is the difference between a cnidocyte and a nematocyst?
A cnidocyte is the stinging cell that is on the outside of a Cnidarian's tentacles that cause stinging. a nematocyst is a barb that is on the inside of the cnidocyte that shoots out and hooks on to the victim of the cnidarian's sting.
3. How does a nematocyst fire?
the barb on the outside of the cnidocyte touches something and is triggered, this opens the operculum, and the nematocyst fires out, injecting venom.
4. In Obelia, describe the role of each type of polyp and the medusa
Obelia is Polyp dominant, so it spends most of its life in the polyp stage. the role of the Obelia Poluyp is to determine whether or not the area it lives in is sutable for it's medusa offspring. if it determines that the environment is safe, it will reproduce medusa by budding and release them into the water. because the Obelia doesnt stay in the medusa stage for very long time before they reproduce and form polyps, the medusa's job is basically to spread the species.
5. How is the Portuguese Man-O-War similar and different to Hydra and Obelia?
The Man-O-War and the hydra and obelia have tentacles with cnidocytes, a large, non-stinging body, has one spot that acts as a mouth and anus, both belong to Cnidaria, . Only the Man-O-War is much larger, lives in salt water, and has a sting that can cause severe pain to humans. they are different because the Man-O-Wa belongs to class Scyphozoa, and Obelia and hydra belong to class Hydrozoa. this means the Man-O-War spends much more time as a medusa, and mush less time as a polyp than the Obelia and Hydra.
Live Hydra lab
Purpose: To observe a live hydra under a microscope and record observations.
Observations: a) colour: salmon
b) size: 1 mm long.
c) # of tentacles: 5
d) body shape: fuzzy head/bloom, several tentacles at posterior.
e) how does the hydra react to a tap on the slide: no visible reaction.
f) how does the hydra react to a pin prick: twitched, attempted to attach to it
g) what part of the body was most responsive: the tentacles
h) How and why the hydra uses cnidocytes: the barbs on the cnidocytes are triggered, and the nematocyst shoots out and injects venom, the reason they fire, is to kill prey and fend off predators.
i) how does the hydra react to being away from the light: no visible response
j) how does the hydra respond to a drop of acetic acid: pulls its tentacles towards its body rapidly.
k) explain the purpose of the hydra's bud: the hydra can reproduce asexually via 'budding.' the bud grows into another hydra and detaches itself from the parent.
Observations: a) colour: salmon
b) size: 1 mm long.
c) # of tentacles: 5
d) body shape: fuzzy head/bloom, several tentacles at posterior.
e) how does the hydra react to a tap on the slide: no visible reaction.
f) how does the hydra react to a pin prick: twitched, attempted to attach to it
g) what part of the body was most responsive: the tentacles
h) How and why the hydra uses cnidocytes: the barbs on the cnidocytes are triggered, and the nematocyst shoots out and injects venom, the reason they fire, is to kill prey and fend off predators.
i) how does the hydra react to being away from the light: no visible response
j) how does the hydra respond to a drop of acetic acid: pulls its tentacles towards its body rapidly.
k) explain the purpose of the hydra's bud: the hydra can reproduce asexually via 'budding.' the bud grows into another hydra and detaches itself from the parent.