Acoelomates Platyhelminthes - Mount Allison · PDF file- a closed system of canals that...
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Transcript of Acoelomates Platyhelminthes - Mount Allison · PDF file- a closed system of canals that...
Porifera
Cnidaria Ctenophora Platyhelminthes Rotifera
Nematoda Nemertea Mollusca Annelida Arthropoda Bryozoa
Phoronida Brachiopoda Echinodermata Chordata
No true tissues
radial symmetry diploblastic
true tissues
Acoelomates
Deuterostomes
Bilateral symmetry triploblastic
Body cavity
Protostomes
Lophophorate phyla
Pseudocoelomates
Coelomates
A Phylogeny of the Animal Phyla
Echinodermata - the starfish, urchins, sea cucumbers, sand dollars
Echinodermata - the starfish, urchins, sea cucumbers
• Description Echinoderms are • deuterostomes • have a water vascular system • have hardened plates (ossicles) in their epidermis • pentaradial symmetry
General anatomy of a starfish
General anatomy of a starfish
Ampulla
Anus Cardiac stomach
Pyloric stomach Tube foot Mouth
Ring canal
Madreporite
Radial canal
Ossicles
Ring canal
Stone canal
Echinodermata - the starfish, urchins, sea cucumbers
Water vascular system - a closed system of canals that echinoderms use for
locomotion
Echinodermata - the starfish, urchins, sea cucumbers
Water vascular system - a closed system of canals that echinoderms use for
locomotion
Echinodermata - the starfish, urchins, sea cucumbers
Water vascular system - by using water pressure echinoderms can crawl along by
moving individual “tube feet” along their bodies
Echinodermata - the starfish, urchins, sea cucumbers
Water vascular system - by using water pressure echinoderms can crawl along by
moving individual “tube feet” along their bodies
Ampullar muscles
Longitudinal muscles
Circular muscles
To extend foot
1) Flex ampullar muscle 2) Relax longitudinal muscle 3) Flex circular muscles
Echinodermata - the starfish, urchins, sea cucumbers
Ossicles
Echinodermata - Who are they?
Asteroidea - Sea stars (starfish) - active predators, with small ossicles in their epidermis
Echinodermata - Who are they?
Echinoidea - Sea urchins - grazers, with ossicles fused to form a test
Echinodermata - Who are they?
Echinoidea - Sand dollars - grazers, with ossicles fused to form a test
Echinodermata - Who are they?
Holothuroidea - Sea cucumbers - bottom feeders, with very reduced (or absent) ossicles
Phylum Class Order
Porifera Calcarea
Demospongia
Hexactinellida
Platyhelminthes Turbellaria (free-living)
Trematoda (flukes)
Cestoda (tapeworms)
Mollusca Polyplacophora (chitons)
Gastropoda (snails,slugs)
Bivalvia (clams, oysters)
Cephalopoda (octopus, squid)
Annelida Oligochaeta (earthworms)
Hirudinea (leeches)
Polychaeta (marine worms)
Arthropoda Chelicerata (spiders, mites, scorpions)
Myriapoda (centipedes, millipedes)
Uniramia (insects)
Crustacea (crayfish, lobsters, crabs, barnacles)
Taxa we have looked at so far
Phylum Class Order
Echinodermata Asteroidea (Sea stars [=starfish])
Echinoidea (sea urchins, sand dollars)
Holothuroidea (sea cucumbers
Taxa we have looked at so far
Diversity of Life���- Chordata-���
Chordata - lancets, sea squirts, vertebrates
• Description Chordates are deuterostomes, with a dorsal hollow nerve cord, gill slits, a post-anal tail and a notochord
Chordata - Chordate evolution - Ancestral forms - Lancet Worms (Amphioxus) ���
Notochord
Nerve cord
Myomeres
Chordata - Chordate evolution - Ancestral forms - Lancet Worms (Amphioxus) ���
Sea Squirts - Urochordates (Tunicates)
Sea Squirts - Urochordates (Tunicates)
Sea Squirts - Urochordates (Tunicates)
Chordate Phylogeny (so far)
Urochordata (tunicates)
Cephalochordata (Amphioxus) Craniata
Chordata - Chordate Evolution
Chordates acquire over time:
1. A distinct head - Craniates (most are extinct)
2. A backbone
3. Jaws
Chordata - Chordate Evolution Today
Chordata - Chordate evolution - Craniates
One surviving group - hagfish - head but no backbone
Chordata - Chordate evolution - Craniates
One surviving group - hagfish - Scavengers
Chordata - Chordate evolution - Vertebrates - craniates with a backbone
Jawless vertebrates - Agnatha - Lamprey
Chordata - Chordate evolution - Vertebrates - craniates with a backbone
Jawless vertebrates - Agnatha – Lamprey - fish parasites
From Craniate to Vertebrate
Hagfish
Lamprey
Fibrous sheath
Notochord
Gnathostomes
Cartilage
Bone
Next time: Fish and more….