5. major phyla a. porifera: sponges b. cnidaria: corals, hydra, anemones, jellyfish protostomes:...

5. Major Phyla

a. Porifera: Spongesb. Cnidaria: Corals, Hydra, Anemones, Jellyfish

Protostomes: Lophotrochozoansc. Platyhelminthes: Flatwormsd. Annelida: Segmented wormse. Mollusca: Chitons, snails, bivalves, cephalopods

Protostomes: Ecdysozoans

5. Major Phyla

Protostomes: Ecdysozoansf. Nematoda

- molt four times, resecreting their cuticle each time

- complete digestive tract

- some cephalization with anterior neural ganglion

- free living and parasitic

-human parasites: trichinosis, filariasis, elephantiasis, Ascariasis (two foot intestinal worms)

5. Major Phyla

Protostomes: Ecdysozoansf. Nematodag. Tardigrada

Cryptobiotic: can dehydrate to less than 1% of normal and endure for 10 years.

Can endure the vaccuum of space and 6000 atmospheres of pressure.

Thin exoskeleton, unjointed legs

5. Major Phyla

Protostomes: Ecdysozoansf. Nematodag. Tardigradah. Onychophora

Sister group to the Arthropods; thin exosleleton and unjointed legs, like tardigrades

Predatory; immobilize prey by shooting glue

5. Major Phyla

Protostomes: Ecdysozoansf. Nematodag. Tardigradah. Onychophora i. Arthropoda

Chelicerata

Arachnomorpha

Trilobita

Arachnids

Xiphosura

Mandibulata

Myriapoda

Hexapods

Remipedes

Vericrustacea

Crustacea

ExoskeletonJointed legs

From Regier et al. (2010)

5. Major Phyla

Protostomes: Ecdysozoansf. Nematodag. Tardigradah. Onychophora i. Arthropoda

Arachnomorpha clade:

Includes trilobites and Chelicerates. The chelicerates have two body regions, the cephalothorax and abdomen. They also have only one pair of appendages before the mouth – usually pincers. In spiders, these are fangs that inject poison.

5. Major Phyla

Protostomes: Ecdysozoansf. Nematodag. Tardigradah. Onychophora i. Arthropoda

The Mandibulata clade:Includes the myriapods (centipedes and millipedes) and crustaceans and their descendants (the hexapods). So, insects are the terrestrial descendants of crustaceans.

5. Major Phyla

Protostomes: Ecdysozoansf. Nematodag. Tardigradah. Onychophora i. Arthropoda

So in the mandibulata clade, we see duplication (myriapods), specialization (crustaceans), and reduction/fusion (insects)

5. Major Phyla

Protostomes:Deuterostomes:

j. Echinodermata

Internal skeleton composed of interlocking plates of calcium carbonate. A system of internal canals fills and empties tube feet.

5. Major Phyla

Protostomes:Deuterostomes:

j. Echinodermatak. Hemichordata

Hollow dorsal nerve cordPharygeal gill slits

All marine – some reach 8 ft in length

5. Major Phyla

Protostomes:Deuterostomes:

j. Echinodermatak. Hemichordatal. Chordata

4 characteristics: - hollow dorsal nerve chord - notochord - pharygeal gill slits - post-anal tail

5. Major Phyla

Protostomes:Deuterostomes:

j. Echinodermatak. Hemichordatal. Chordata

subphyla: Urochordata Cephalochordata Vertebrata

“Tunicates”: Mobile larvae, sessile filter-feeding adults - filter with the pharynx and gill slits.

5. Major Phyla

Protostomes:Deuterostomes:

j. Echinodermatak. Hemichordatal. Chordata

subphyla: Urochordata Cephalochordata Vertebrata

Mobile larvae, sessile filter-feeding adults - filter with the pharynx and gill slits.

5. Major Phyla

Protostomes:Deuterostomes:

j. Echinodermatak. Hemichordatal. Chordata

subphyla: Urochordata Cephalochordata Vertebrata

Pikaia – the earliest Chordate – dates from the Cambrian period

5. Major Phyla

Protostomes:Deuterostomes:

j. Echinodermatak. Hemichordatal. Chordata

subphyla: Urochordata Cephalochordata Vertebrata

“Jointed spine” – vertebrae. Although Hagfish lack this, so sometimes the group is called Craniata (has a skull)

Patterns in evolution:

Innovation, radiation, competitive contraction

5. Major PhylaDeuterostomes: l. Chordata

Vertebrata

Hyperoartia: “Jawless fishes” Lampreys and Hagfish

Lamprey larvae look very much like cephalochordates

5. Major PhylaDeuterostomes: I. Chordata

Vertebrata

Hyperoartia: “Jawless fishes”

Evolve in late Cambrian, radiate in the Ordovician

5. Major PhylaDeuterostomes: l. Chordata

Vertebrata Gnathostomes – Jawed Vertebrates

Move from detritivores to predators

Lobe-finned Fishes

Ray-finned Fishes

Bony Fish

Acanthodians

Teleosts

Chondrichthyes (Sharks, rays)

PlacodermsArthrodires

Antiarchs

5. Major PhylaDeuterostomes: l. Chordata

Vertebrata Gnathostomes – Jawed Vertebrates

The Devonian was the “Age of Fishes” – a radiation of the first jawed vertebrates, dominated first by the Placoderms and then by Cartilaginous and bony fishes

5. Major PhylaDeuterostomes: l. Chordata

Vertebrata Gnathostomes – Jawed Vertebrates

The Devonian was the “Age of Fishes” – a radiation of the first jawed vertebrates, dominated first by the Placoderms and then by cartilaginous and bony fishes

5. Major PhylaDeuterostomes: l. Chordata

Vertebrata Gnathostomes – Jawed Vertebrates

Bony fishes dominate today: lighter skeleton and swim bladder

Ray-finned Fishes Lobe-finned Fishes

5. Major PhylaDeuterostomes: l. Chordata

Vertebrata Gnathostomes – Jawed Vertebrates

Bony Fishes (Osteichthyes) comprise 40% of living vertebrate species