Acoelomates and Pseudocoelomates Flashcards
(49 cards)
What defines pseudocoelomates in terms of their body cavity?
They have a body cavity only partially lined with tissue derived from mesoderm.
Where are nematodes commonly found?
Extremely abundant in marine and freshwater sediments, soil water, and interstitial spaces.
What roles do nematodes play ecologically?
Important in decomposition and nutrient cycling; also include parasites of humans, plants, and animals.
What are some parasitic examples of nematodes affecting humans?
Hookworms, ascarids, and filarial nematodes (which block lymphatic systems).
How are some nematodes beneficial to humans despite being harmful?
Several entomopathogenic nematodes kill insects/molluscs and are used to control pests like yellowjackets and slugs.
What is unique about rotifers’ anatomy and locomotion?
They have a ciliated crown (corona) for swimming or crawling, a trunk often with a spiny lorica, and feed on protozoans.
How do rotifers reproduce?
Mainly sexual reproduction, but can reproduce by parthenogenesis under favorable conditions.
What are gastrotrichs and how do they move?
Bottle-shaped, ventrally ciliated micro-animals that glide on surfaces using ventral cilia.
What is notable about Nematomorpha’s lifecycle?
Juveniles are parasitic in arthropods; adults are free-living, non-feeding in freshwater or damp soil.
Describe Acanthocephala.
Endoparasites with spiny proboscis, infect vertebrates, use arthropod intermediate hosts.
What are Kinorhyncha and Loricifera?
Microscopic marine sediment burrowers with spiny anterior ends; Loricifera have a cuticular lorica girdle.
What unique feature does Priapulida have?
An introvert with teeth at the tip used to capture and pull in prey.
How are Entoprocta different from Bryozoans?
Entoprocta have anus inside the ring of tentacles; most are colonial and attached to substrates.
What distinguishes a true coelomate from pseudocoelomates?
Coelomates have a fluid-filled body cavity completely lined with mesodermal tissue.
What is the peritoneum?
The epithelial tissue layer lining the coelom in eucoelomate animals.
What is a mesentery?
A fold of peritoneum that suspends organs inside the coelom.
How is segmentation organized in annelids?
Linear series of segments separated externally by grooves and internally by septa; each segment has its own nervous, excretory, and reproductive systems.
What role do muscles play in annelid movement?
Longitudinal and circular muscles surround the coelom, working as a hydrostatic skeleton.
What are the three main classes of annelids?
Polychaetes, Clitellata, and Sipuncula.
What lifestyle differences exist among polychaetes?
Some are mobile swimmers (errant) with well-developed sense organs; others are sedentary, with specialized gills or tentacles for feeding.
Where are nematodes commonly found?
In marine and freshwater sediments, soil water, and as parasites of humans, plants, and animals.
What are the key physical features of nematodes?
Long, cylindrical bodies tapered at both ends with a thick, tough cuticle.
What ecological role do nematodes play?
Important in decomposition and nutrient cycling.
Name some human parasitic nematodes.
Hookworms, ascarids, and filarial nematodes
