Lecture 8 Flashcards
What are the key features of the protostomia?
They can be acoelomate, pseudocoelomate or coelomate
Spiral, determinate cleavage
Schizocoelus
Mouth develops from the blastopore
What are the key features of the deuterostomia?
All coelomate
Radial, indeterminate cleavage
Enterocoelus
Anus develops from the blastopore
What does schizocoelus mean?
Mesoderm develops between the gut and ectoderm with the coelom forming as a slit within the solid mesoderm
What does enterocoelus mean?
Mesoderm buds from wall of developing gut splitting off to form the coelom retaining the slit
Mesoderm buds from wall of developing gut splitting off to form the coelom retaining the slit
There are about 7000 species
Evolved independently of lophotrochozoa for over 500 million years
What are the ecological features of the Echinodermata?
All are marine and sessile or slow moving
What type of symmetry is found in Echinodermata?
Pentaradial symmetry (though the larvae are bilaterally symmetrical showing them to have evolved from a bilateral ancestor)
What vascular system is seen in Echinodermata?
They have a unique water vascular system which consists of a madreporite (water inlet), ring canal, radial canal tube feet and ampullae (muscels which contract to increase local pressure)
What organ systems are seen in the echniodermata?
A complete gut with a ventral mouth, central stomach and dorsal anus including digestive enzymes
Movement is controlled by radial nerves
Gonads are in arms
What three groups are the chordata?
Urochordata (tunicates)
Cephalochordata (lancelets)
Vertebrata ( vertebrates)
What are the defining characteristics of the chordata?
Dorsal, hollow nerve cord, post anal tail, notochord, pharyngeal slits (slits in the pharynx which allow ingested water to be returned to the water)
