Acoelomates and pseudocoelomates Flashcards
what is an acoelomate
organisms with a solid body with the area filled with mesoderm cells
what is a pseudocoelomate
organisms with a fluid filled body cavity partially lined with tissue derived from the mesoderm
outline the characteristics of pseudocoelomates
- covered by a cuticle
- no organs for gas exchange
- poorly cephalised
- complete digestive tract
- interstitial fauna
what are the 9 phylum of pseudocoelomate
1) nematoda
2) rotifera
3) gastrotricha
4) nematomorpha
5) acanthocephala
6) kinorhynca
7) loricifera
8)priapulida
9) entoprocta
outline some characteristics of the phylum nematoda
- long, cylindrical and tapered at both ends
- thick cuticle
- important in decomposition
- feed on animal and plant fluids
give some examples of parasitic nematoda found in humans
1) hookworms = juviniles enter skin of feet enter blood stream and carried to lungs were they are swallowed into the intestine for adult stage
2) ascarids = eggs ingested through faecal contamination
3) filarial nematodes = vector born and cause blockages in the lymphatic system
what is elphantiasis
caused by the parasite filarial nematode which causes blockages in the lymphatic system
how can parasitism be exploited
some parasites are highly host specific which can be used to form a biological control as the parasite only affects a single species
outline some characteristics of the phylum rotifera from the pseudocolemate
- trunk with lorica and posterior foot with adhesive glands
- anterior end has a crown of cilia called the corona
- swim with cilia
- fresh water mostly
outline the characteristics of the phyla gastrotricha from pseudocolemates
- bottle shaped body with ventricle surface ciliated in stomach hairs
- glide on surfaces propelled by ventrical cilia
- feed on bacteria
- life span less than 40 days
outline characteristics from the phylum nematomorpha from the pseudocolemates
- mostly fresh water
- long hair like bodies 40cm long
- closley related to nematodes
- juviniles parasitic in arthropods with adults being free living in water
- cause hosts to drown themseleves
outline the characteristics of the phylum acanthocephala from pseudocolomates
- endoparasities of aquatic and terrestrical vertebrate digestive systems
- less than 5cm big
- anthropoids are the immediate host
outline the characteristic of the phylum kinorphyncha
anterior end of the body is spiny
micorscopic animals that burrow through marine sediments
outline the phylum loricifera
- identified in 1983
- marine sediments
- abodmen has a lorica
- 0.25mm long
- spiny anterior end
outline characteristics from the phylum priapulida
- worm like marine animals
- burrow in sand and mud
- anterior forms an introvert which can be pushed in and out
- teeth present at the end of the intoverted for prey
outline the characteristics of the phylum entoprocta
- anus inside ring of tentacles
- all marine bar one species
- attached to rocks and shells
- less than 5mm in size
what is a coelomate
organisms with a fluid filled body cavity completely lined with tissue derived from the mesoderm
what is the peritoneum
the tissue lining the eucoelomate animals is a layer of epithelial cells
the peritoneum is always Infront of internal organs
what is a mesenterey
when organs extend so far into the coelom they become suspended by a fold of the peritoneum called the mesentery
what are the colemate phyla divided into
1) protostomes
2) deuterostomes
3) lophophorates
separated based on embryology
what is an annelida
a phylum of protostome’s in coleomate organisms with elongated bodies
their coleom is surrounded by longitudinal and circular muscles bands forming a hydrostatic skeleton
what is meant by metameric segmentation
the bodies are composed of repeated segments with a cilium which lines it (repeated organs in each segment)
what are the 3 classes under the phylum annelida
1) polychaetes
2) clitellata
3) sipuncula
what is a polychaeta
a class in the phylum annelidia with two parts to is head
1) prostomium which carries sense organs
2) peristomeum which carries tentacles and a mouth
what are the two divisions of the class of polychaeta in the phylum annelidia
1) errant = mobile forms
2) sedentary = sessile forms
what is a clitellata
a class of organisms in the phylum anneldia including earthworms
- reduced head and no appendages
- has a clitellum
- diet of DOM
what is a clitellum
a thick glandular section of the body wall which secretes a viscid sac in which eggs are deposited
