protostomes coelomates mouth develops from the blastopore cleavage is radial and determinate all...
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ProtostomesCoelomates
• Mouth develops from the blastopore
• Cleavage is radial and determinate
• ALL HAVE A TRUE COELOM!
Subkingdom EumetazoaBilateral symmetry
CoelomatesPhylum Mollusca
• Soft bodied, with hard shell protection • Ex: slugs, clams, snails, squids, and octopuses• Open circulatory system – fluid not always contained
within vessels but circulates through hemocoel• Most have exoskeletons• Reduced or no segmentation• Radula; rasping tongue to scrape food• Many internal organs – excretion through • Three body parts
– Muscular foot - movement– Visceral mass – contains most of the organs– Mantle – secretes a shell
Four classes of Phylum Mollusca
• Polyplacophora – Chitons– Cling to rocks– Live on rocky shores– Use muscular foot to grip
• Gastropoda– Snails, slugs, nudibranchs– Largest class– Shell protects body– Torsion leads to twisted body– Uses radula to scrape algae and graze on
plants
• Bivalvia:– Clams, oysters, mussels, scallops– Possess shell divided and hinged into two halves– Filter feeders– Sedentary lifestyle
• Cephalopoda– Squid and octopus and nautilus– Use jaws to bite prey– Mouth as base of foot (foot drawn into several
tentacles)– Complex brains and capable of learning and
moving fast– Mantle reduced or absent– Can get large, How?
Subkingdom EumetazoaBilateral symmetry
CoelomatesPhylum Annelida
• SEGMENTATION – internal and external• Closed circulatory system • Closed digestive system with specialized regionss• Excretion from each segment through tubes
(metanephridia)• Nervous system with ganglia and ventral nerve cords
Three classes of Phylum Annelida
• Oligocheates– Earthworms
• Polycheates:– Fanworms– Tube dwellers (marine)
• Hirudinea:– Leaches– Used to treat bruised tissues and to stimulate
circulation
Evolutionary trends in Annelids
• Coelom – serves as hydrostatic skeleton– Developed complex organ system– Protects internal structures
• Segmentation– Specialization of body segments
Phylum Arthropoda
• Key characteristics:– Segmentation– Hard exoskeletons of chitin– Jointed appendages– Open circulatory system– Extensive cephalization– Gas exchange gills in water, book lungs or
spiracles on land– Ventral nervous cords– Metamorphosis (insect)
• Incomplete: egg, nymph, adult• Complete: egg, larva, pupa, adult
Success vs. Limitations
• Successes:– Exoskeleton, lets the thrive on land, but
limited– Jointed appendages allowed for walking
and then flying in some– More successful organization of segments
• Limits:– Exoskeleton is shed– Limited brain size– Limited body size
Subphyla• Trilobites
– Extinct group– Show pronounced segmentation, with little
variation in appendages– Early, primitive arthropods
• Chelicerates– Includes the arachnids– 1-2 body segments with 8 legs
• Uniramia– Includes insects, milipedes and centipedes
Classes of Phylum Anthropoda
• Arachnids– Scorpions, spiders, mites
• Insects– 1pair of antennae– 6 legs– 3 body segments
• Crustaceans– Crabs, crayfish, lobsters, isopods (pill bugs)– 2 or 3 body segments
Subkingdom EumetazoaBilateral symmetry
Deuterostomes
• Radial indeterminate cleavage
• Blastopore becomes the anus
• Secondarily evolved radial symmetry
• Unique water vascular system
• Has mouth and anus
• Has endoskeleton
Subkingdom EumetazoaBilateral symmetry
DeuterostomesEchinoderms
Phylum EchinodermPhylum Chordata
Classes of Phylum Echinoderm
• Aseroidea– Sea stars
• Ophiuroidea– Brittle stars
• Echinoidea– Sea urchins and sand dollars
• Holothuroidea– Sea cucumbers
What evolutionary innovation both led to and limited the success of the
phylum to which this organism belongs?
. . . the exoskeleton
What evolutionary innovation does the phylum to which this organism
belongs have over Nematoda?
. . . segmentation
What is unique about the digestive system of this organism, and others
that belong to the same phylum?
. . . it is one way; having both a mouth and an anus
What two evolutionary innovations are common to the phylum to which
this organism belongs?
. . . bilateral symmetry and celphalization
What type of symmetry does this organism, and others belonging to
the same phylum, exhibit?
. . . radial symmetry
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