Term
Pseudocoelomates
Body characteristics
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Definition
With pseudocoel
“false body cavity”
Blastocoel persists between body wall and gut
§becomes pseudocoel (or “pseudocoelom”) |
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Term
Development of Pseudocoelomate |
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Definition
Blastula
Gastrulation
Mesoderm formation
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Term
Pseudocoelomates
body characteristics
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Definition
Has muscle (mesoderm), part of body wall
No muscle(mesoderm) around gut (endoderm)
Cuticle secreted by epidermis:
-made of chitin
- Molting for Growth
- recent classifications place with Arthropods (both phyla molt to grow) |
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Term
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Definition
Primarily aquatic/marine, some terrestrial
Meiofauna:
-Live in spaces between grains of soil, sediments
Many very small> no respiratory and circulatory systems.
Many are Parasitic |
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Term
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Definition
Phylum Rotifera
Phylum Nematoda |
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Term
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Definition
Usually cone or wine-glass shape
Ring of cilia around mouth
Early observers mistook for rotating wheel
Mastax, “jaws” of a rotifer |
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Term
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Definition
Live in freshwaters, oceans
Some live on mosses, lichens
Can be dried and will revive when moistened
3-4 years common
50+ years reported |
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Term
Phylum Rotifera
Reproduction |
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Definition
Usually parthenogenic (exhibit parthenogenesis)
Asexual reproduction
Female lays asexual eggs-> females
->females, generation after generation.
Copies successful genome exactly
Favored in stable environment |
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Term
Phylum Rotifera
Reproduction 2 |
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Definition
Sexual alternative
Females produce some males (sci. doesn't know how or when)
Males inseminate females, which produce sexual eggs
Offspring more variable
–Some variants survive better than others |
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Term
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Definition
Largest pseudocoelomate phylum
estimated 20,000 species
Worldwide in all imaginable habitats
Deep sea to mountain tops
Glaciers to hot springs
Feed on all kinds of organic materials |
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Term
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Definition
Body form worm-like
-Slender, tapered at ends
-Mostly less than 2.5 mm long, 0.1 mm wide
Mouth with 6 (primitive) or 3 “lip-lobes” (primitive 6 fused into 3)
-May have sensory bristles, teeth, etc. |
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Term
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Definition
Muscles longitudinal only
Produces thrashing wiggle
Normal locomotion through sediments, push against solid particles
Muscle cell extensions to nerves
No peripheral nerves! |
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Term
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Definition
All adults of same species have same number of cells (and same # of cells in organs)
•959 somatic cells (gametes variable)
•302 nerve cells
*Caenorhabditiselegans used in study.*
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Term
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Definition
Most free-living in soils and sediments
-important part of ecosystems
some agricultural pests
some parasites in domestic animals (heartoworm) and humans (tapeworms)
*138 species use Homo Sapiens as host.* |
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Term
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Definition
Mutualism: Benefits host and symbiont
ex. Lichen (fungus + algae), Termite (insect + ciliate protozoans)
Commensalism: Benefists symbiont, but doesn't benefit or harm host
ex. Epiphytic plants on trees (mosses, ferns, smanish moss, many orchids), Ramora and Shark
Parasitism: Harms host and benefits symbiont or "parasite"
ex. Roundworms and Flatworms |
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Term
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Definition
Complex life cycles
Free-living and parasitic stages
Intermediate hosts
Enormous numbers of offspring!!
105 eggs per day x 1000 days = 100,000,000 eggs per female |
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Term
Parasitism
modes of transmisson |
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Definition
Ingestion of food: Trichinellaspiralis> trichinosis from pork.
-Larva creates cysts in muscles. Passed on when host dies and is esated by next host.
Ingestion of feces: Ascaris spp.
infects ~ 1.5 billion people = 25% of world population
Pinworm-common in children in North America
Entry through skin: Hookworms-Human and Canine
Transmission by vector (any other organism thqat carries the parasite): Filarial worms- Filariasis (Elephantiasis)
Onchocerca-river blindness
Canine heartworm
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Term
| Canine Heart Worm Life Cycle |
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Definition
Adult in dog heart,
Larvae in blood ingested by mosquito,
Residence in mosquito,
Bite transfers infective larvae to new canine
host. |
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