Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
38 Cards in this Set
- Front
- Back
|
Cnidaria and Ctenophora
|
Cnidaria and Ctenophora ‘Jellyfish’, Hydra and anenomes, corals and comb jellies
• Evolutionary Advances beyond Porifera: tissues, symmetry • Defining Characteristics -Polyp and medusa anatomies -Feeding: cnida and nematocysts; digestion, symbiosis in corals -Reproduction: sexual and asexual -Circulation and gas exchange |
|
|
Diploblastic embryos
|
• Diploblastic embryos- radial symmetry, have nerve and muscle cells
1. Ctenophora are comb jellies 2. embroyonic – radial cleavage, zygote make parallel division 3. gastrulation- bastula gastrulation |
|
|
2 Primary Tissue Layers
|
• Ectoderm forms epidermis
• Endoderm forms gastrodermis • Many have jelly-like, supportive layer in between: mesencyme or mesoglea |
|
|
Complex Life cycles (Polyp and medusa stages)
|
• One opening gut
• Blind gut (no anus) • Cnidocytes (cells with stinging or trapping organelles like nematocysts) • Medusa sexual stage, larvae on substratepolyps undergo asexual reproduction - 1) leave bits of themselves around.. so more polyps -- produce medusa through segmentation, grow them and pop them off.. -free swimming medusa (complete) • Can capture food while they’re still immature .. |
|
|
Phylum Ctenophora has
|
• One way gut (anal canal) -
• ‘comb plates’ with cilia for swimming locomotion, cilia in groups in a coordinated fashion • Colloblast cells that produce glue to catch prey • No polyp stage, never colonial, no nematocysts • Has bioluminescence, startle predator (glows, green jelly) |
|
|
Hydrozoans and anthozoans spend most time in the polyp form
|
• The polyp- solitary or colonial
• Mostly sessile • Mouth surrounded by tentacles • Radially symmetrical, sometimes branching • Tissues= outer epidermis and inner gastrodermis • Jelly-like mesoglea between epidermis and gastrodermis |
|
|
Gastrodermic lines the gut (gastrovascular cavity)
|
• Functions: digestion and circulation of digested materials
|
|
|
The Medusa
|
• Solitary, free swimming (macroplankton)
• Mesogleal layer (mesenchme) generally thickened- jelly like • Radial canals extend the gastrovascular cavity through the body. • Ring canal around the edge of the ‘umbrella’- • Jelly like skeleton thickens, help animal keep its shape and contract again |
|
|
Macro-plankton
|
big thing that can’t swim well
|
|
|
Usually Carnivores
|
• Cnidocyte cells expel singers, lassoes or adhesives
• ‘Nematocysts’ are cnida that sting and capture prey (poisonous) - Explosion is striggered by cnidocil hair, prey chemicals (2 meters/sec) - prey capture, nematcysis, part of cell organelle, generated by noomatysis hair that sticks up… interacts wit lil lid hair.. will shoot out and go right to prey with a lot of prey. Poisions and paraplyze prey (corals produce muscus , trap small particles of prey… and digest whatever prey stuck on sticky substance, mucus net suspension trap) |
|
|
Corals (other Cnidara) may feed in two other ways
|
• Particles trapped in mucus are swept into the polyp mouth by cilia (muscus net suspension feeding)
• Corals can get nutrition from symbiotic algae • Symmetrical- divide in different planes • algae get protected by corals • coral doesn’t usually need algae • environmental stressors can cause coral to get rid of algae • coral bleaching= symbiosis between coral and algae breaks down |
|
|
Why is alternative generations important?
|
• Dispersal (medusa stage)
• Ability to exploit different ecological niches (polyp thrive in hidden environment) • Advantages of both asexuality and sexuality • Asexuality: -propagation of known successful forms -no ‘cost of sex’ (all of own genes passed down, less loss of gametes) • Sexuality -variability of offspring, new genetic combinations |
|
|
Coloniality occurs when identical or nearly identical organisms grow together
|
• Common in species during sexual stages, when offspring do not separate completely from parents
• Continuum between separate individuals, interdependent related individuals (like social insects), and colonial species. • Colonies of polypoid Cnidaria often share gastrovascular cavities |
|
|
Advantages of Coloniality
|
• Food sharing
• Mutual defense • Large size- ability to subdue larger prey and compete against other species, building larger structures (as in coral reefs) • Specialization- not all individuals have to perform all tasks ex. Man-O-War |
|
|
Man-O-War Specialized Zooids
|
• Gastrozooids (gastro = stomach), branched tentacles (up to 13 m!) with cnidae and mouth
• Dactylozooids-defense and prey capture, form long and unbranched tentacles with cnidae, but no mouth • Gonozooids (gono = seed)- reproductive, produce the medusoid stage: No mouth or tentacles • Pneumatophore- (pneumato – air phore = to bera) gas-filled zooid that acts as a float |
|
|
How does a lack of a circulatory system constrain Cnidaria?
|
• All food and gas exchange is local and must move from cell to cell
• Cells reach farther from the surface= less nutrition, less ability to exchange gases and expel wastes • Cube-shaped animal with length of any side x - surface area – 6x (squared) (surface area increases as the square of the linear dimension -volume = x (cubed) (volume increases as the cute of a linear dimension • Volume increases faster than surface area |
|
|
Passive diffusion of gases works best at thickness of only 1 mm
|
• Thin tissues (many cnidarians; those with thick mesoglea have few cells in the mesoglea)
• Small • Long and thin (thread like) • Increase surface area by folding or canals • Flat shape • Adhesives (locomotion…)- |
|
|
Hydrotheca
|
Hydrotheca- epidermis
|
|
|
Pigment
|
Pigment- light sensory cells
|
|
|
Genetic diversity importance?
|
Genetic diversity important because environment might change so asexual and sexual (the one that floats around will be more likely change.
|
|
|
1. What is a cnida, and what is its function?
|
• Intracellular stinging organelle of cnidarians
• Cnidae are produced by specialized cells, cnidocytes and has capsule containing a long coiled thread-like tube -tread bears barbs or spines • After being triggered by a mechanoreceptor, (bristle hair), cnidar discharges explosively as a result of hydrostatic ressure • Cnidae can entangle prey and inject them with toxins. • Double-walled capsule contain toxins called “nematocysts” |
|
|
2. Distinguish between polyp and medusa forms of a cnidarian
|
• Polyp- tube shaped and (usually) sessile form
-anchored to a substrate -ex sea anemones (solitary) and corals (colonial) • Medusa- bell or umbrella shaped organism -free living -Oral end on the concave side of the animal -ex, jellyfish, many cnidarians alternate between a polyp and medusa during life cycle |
|
|
3. Describe the life cycle of a scyphozoan cnidarian
|
• Most scyphozoans have an “alternation of generations” between asexually reproducing polyp stage and a more sexually reproducing medusa stage
• Scyphistoma- asexual polyp is a tiny organism -reproduces asexually • STrobilation- medusa forms are produced (asexually(, scyphistomas now known as strobila undergoes repeated transverse fissioning events • Ephrae- immature medusae (singular: ephyra) -they break loose and deelop into adult medusae (which we call jellyfish) -mature medusa reproduces seuxlaly • Fertilization- open ocean or in the female’s gastrovascular cavity, if followed by a planula larval stage .. |
|
|
4. Why might coloniality be advantageous over living as solitary individuals in the Cnidaria?
|
• -Coloniality produces functional units that are larger in size
-improves feeding efficiency -allow larger prey to be captured -reduce the risk of predation by other animals -ability to monopolize space may also be enhanced -allows specialization among unit within the colony, ex some polyps can specialize on feeding, defense, reproduction, and increase the overall efficiency of each task. |
|
|
5. Explain the concept of mutualism and give one or more examples from the Cnidaria
|
• Mutualistic- relationship between two (or more) kinds of organisms
-both partners gain fitness benefit from the association -ex anemone fish and sea anemone: fish gains protection and food leftovers, -sea anemone enjoy improved ventilation and increased numbers of prey (lured by ten anemone fish) -corals and their symbiotic algae (zooxanthellae.) |
|
|
How does a lack of a circulatory system constrain Cnidaria?
|
• All food and gas exchange is local and must move from cell to cell
• Cells reach farther from the surface= less nutrition, less ability to exchange gases and expel wastes • Cube-shaped animal with length of any side x - surface area – 6x (squared) (surface area increases as the square of the linear dimension -volume = x (cubed) (volume increases as the cute of a linear dimension • Volume increases faster than surface area |
|
|
Passive diffusion of gases works best at thickness of only 1 mm
|
• Thin tissues (many cnidarians; those with thick mesoglea have few cells in the mesoglea)
• Small • Long and thin (thread like) • Increase surface area by folding or canals • Flat shape • Adhesives (locomotion…)- |
|
|
Tentacles in back
|
Tentacles in the back use to capture prey
Tissues- epidermis---- mouth interior gastodermine (underlining) food digestion take places… through chemical breakdown in interior of gut, cell pick up smaller particles (inner digestion) gastrovascular cavity run thoroughly, |
|
|
Hydrotheca
|
Hydrotheca- epidermis
|
|
|
Pigment
|
Pigment- light sensory cells
|
|
|
Larvae swim.. metamorposis with planlula
|
Laravae swim around attach to metamorphosis .. planlula find a good site to attach with food, it attaches to substrate through phrasal disk, attack tentacles, forms a mouth. Cytosoain, fully develop, tentacles, mouth in middle, one way digestive part… move around.. leave lil bits of food on substrate (protosis), has all the tissues in it, differentiate … become fully grown polyp stage. .. will mature. Medusee will be around
|
|
|
Genetic diversity importance?
|
Genetic diversity important because environment might change so asexual and sexual (the one that floats around will be more likely change.
|
|
|
1. What is a cnida, and what is its function?
|
• Intracellular stinging organelle of cnidarians
• Cnidae are produced by specialized cells, cnidocytes and has capsule containing a long coiled thread-like tube -tread bears barbs or spines • After being triggered by a mechanoreceptor, (bristle hair), cnidar discharges explosively as a result of hydrostatic ressure • Cnidae can entangle prey and inject them with toxins. • Double-walled capsule contain toxins called “nematocysts” |
|
|
2. Distinguish between polyp and medusa forms of a cnidarian
|
• Polyp- tube shaped and (usually) sessile form
-anchored to a substrate -ex sea anemones (solitary) and corals (colonial) • Medusa- bell or umbrella shaped organism -free living -Oral end on the concave side of the animal -ex, jellyfish, many cnidarians alternate between a polyp and medusa during life cycle |
|
|
3. Describe the life cycle of a scyphozoan cnidarian
|
• Most scyphozoans have an “alternation of generations” between asexually reproducing polyp stage and a more sexually reproducing medusa stage
• Scyphistoma- asexual polyp is a tiny organism -reproduces asexually • STrobilation- medusa forms are produced (asexually(, scyphistomas now known as strobila undergoes repeated transverse fissioning events • Ephrae- immature medusae (singular: ephyra) -they break loose and deelop into adult medusae (which we call jellyfish) -mature medusa reproduces seuxlaly • Fertilization- open ocean or in the female’s gastrovascular cavity, if followed by a planula larval stage .. |
|
|
Larval stage
|
-larval state is ciliated and swims about.. eventually attaches to the substrate and metamorphoses into a scyphistoma
|
|
|
4. Why might coloniality be advantageous over living as solitary individuals in the Cnidaria?
|
• -Coloniality produces functional units that are larger in size
-improves feeding efficiency -allow larger prey to be captured -reduce the risk of predation by other animals -ability to monopolize space may also be enhanced -allows specialization among unit within the colony, ex some polyps can specialize on feeding, defense, reproduction, and increase the overall efficiency of each task. |
|
|
5. Explain the concept of mutualism and give one or more examples from the Cnidaria
|
• Mutualistic- relationship between two (or more) kinds of organisms
-both partners gain fitness benefit from the association -ex anemone fish and sea anemone: fish gains protection and food leftovers, -sea anemone enjoy improved ventilation and increased numbers of prey (lured by ten anemone fish) -corals and their symbiotic algae (zooxanthellae.) |
