Transcript To what phylum does this organism belong? - Course

Protostomes
Coelomates
• Mouth develops from the blastopore
• Cleavage is radial and determinate
• ALL HAVE A TRUE COELOM!
Subkingdom Eumetazoa
Bilateral symmetry
Coelomates
Phylum 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
An open
circulatory
system
limits the
size of
these
animals
The closed
circulatory
system is
much more
efficient!
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 Eumetazoa
Bilateral symmetry
Coelomates
Phylum Annelida
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•
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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 Eumetazoa
Bilateral symmetry
Deuterostomes
• Radial indeterminate cleavage
• Blastopore becomes the anus
Bilateral symmetry
Deuterostomes
Echinoderms
Phylum Echinoderm
Phylum Chordata
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Secondarily evolved radial symmetry
Unique water vascular system
Has mouth and anus
Has endoskeleton
Classes of Phylum Echinoderm
• Aseroidea
– Sea stars
• Ophiuroidea
– Brittle stars
• Echinoidea
– Sea urchins and sand dollars
• Holothuroidea
– Sea cucumbers
To what phylum does this
organism belong?
Phylum Annelida
To what phylum does this
organism belong?
Phylum Cnidaria
To what phylum does this
organism belong?
Phylum Mollusca
To what phylum does this
organism belong?
Phylum Echinodermata
To what phylum does this
organism belong?
Phylum Arthropoda
To what phylum does this
organism belong?
Phylum Nematoda
To what phylum does this
organism belong?
Phylum Platyhelminthes
To what phylum does this
organism belong?
Phylum Porifera
What evolutionary innovation both
led to and limited the success of the
phylum to which this organism
belongs?
. . . the exoskeleton
What type of symmetry does this
organism exhibit?
. . . none
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
What evolutionary innovation is first
exhibited by the phylum to which this
organism (a giant squid) belongs?
. . . the coelom