A Phylogeny of the Animal Phyla Porifera No true tissues Cnidaria radial symmetry diploblastic Ctenophora Acoelomates Rotifera Pseudocoelomates Nematoda Nemertea Mollusca Protostomes true tissues Annelida Arthropoda Bilateral symmetry triploblastic Bryozoa Lophophorate phyla Body cavity Phoronida Coelomates Brachiopoda Echinodermata Chordata Deuterostomes

Animal Diversity -Vertebrates -

Evolution of Vertebrates -from one lineage of craniates 1. Increased in bony layers around skull and spinal column Cartilaginous precursors of vertebrae

Early Vertebrates Conodonts

Conodonts

Jawless armoured vertebrates Hemicyclapsis Drepanaspis Anglapsis Pterapsis

Vertebrate Jaw First fish with jaws - Placoderms

Vertebrate Jaw First fish with jaws - Placoderms

Vertebrate Jaw

Vertebrate Jaw

Vertebrate Jaw

Vertebrate Jaw

Chordata - Chordate evolution - Vertebrates - craniates with a backbone Jawed vertebrates - Gnathostomes - most primitive group - Chondrichthyes - sharks, skates and rays -skeleton is made of cartilage not bone

Chordata - Chordate evolution - Vertebrates - craniates with a backbone Chondrichthyes - sharks, skates and rays Jaw of a shark - mineralized Rows of forward-moving teeth

Chordata - Chordate evolution - Vertebrates - craniates with a backbone So far: Cephalochordates Lampreys – jawless animals with the beginnings of vertebrae Conodonts – vertebrates with jaw-like elements Placoderms – extinct vertebrates with well developed jaws Chondrichthyes – jawed fish with largely cartilaginous skeletons

Chordata - Chordate evolution - Vertebrates - craniates with a backbone Now - fish with jaws and bony skeletons Lobed fin Divided into two groups Ray fin

Chordata - Chordate evolution - Vertebrates - craniates with a backbone Jawed vertebrates - Gnathostomes - the fish (Osteichthyes) Lobe fins (Latimeria)

Chordata - Chordate evolution - Vertebrates - craniates with a backbone Jawed vertebrates - Gnathostomes - the fish (Osteichthyes) Lobe fins Lungfish

Chordata - Chordate evolution - Vertebrates - craniates with a backbone Jawed vertebrates - Gnathostomes - the bony fish (Osteichthyes) Ray fins

Chordata - Chordate evolution - Vertebrates - craniates with a backbone Jawed vertebrates - Gnathostomes - the bony fish (Osteichthyes) Bouyancy

Chordata - Chordate evolution - Vertebrates - craniates with a backbone Jawed vertebrates - Gnathostomes - the bony fish (Osteichthyes) Bouyancy

Chordata - Chordate evolution - Vertebrates - craniates with a backbone Jawed vertebrates - Gnathostomes - the bony fish (Osteichthyes) Labyrinth organ Sound wave Swim bladder Weberian ossicles

Next move for vertebrates Invasion of land

Move onto Land - Legs Humerus Radius Ulna Lobed fin fish Fossil amphibian

Move onto Land - Legs Lungfish

Move onto Land - Legs Pelvic and pectoral girdles Latimeria Ichthyostega No contact with spinal column Contact with spinal column

Invading Land Ichthyostega

Chordata - Chordate evolution - Vertebrates - craniates with a backbone Jawed vertebrates - Gnathostomes - Tetrapoda - Amphibia Amphibians - first living vertebrates with legs than can support their weight first vertebrates on land -BUT still must return to the water to reproduce

AMPHIBIA GROUPS 1. Urodela (Caudata) Salamanders

AMPHIBIA GROUPS 1. Urodela (Caudata) Salamanders

AMPHIBIA GROUPS 1. Urodela (Caudata) Salamanders - Reproduction spermatophore

AMPHIBIA GROUPS 1. Urodela (Caudata) Salamanders - Reproduction Must return to the water to lay eggs

AMPHIBIA GROUPS 2. Salientia (Anura) Frogs and Toads

AMPHIBIA GROUPS 2. Salientia (Anura) Frogs and Toads Amplexus

Loss of limbs and girdles AMPHIBIA GROUPS 3. Gymnophiona (Apoda) Loss of limbs and girdles

AMPHIBIA GROUPS 3. Gymnophiona (Apoda) Normal mating – female guards eggs

Next step Breaking the reliance on water Opens up terrestrial habitats to vertebrates

Chordata - Chordate evolution - Vertebrates - craniates with a backbone Jawed vertebrates - Gnathostomes - Tetrapoda - Reptilia Reptiles development of a scaly skin to prevent water loss

Chordata - Chordate evolution - Vertebrates - craniates with a backbone Jawed vertebrates - Gnathostomes - Tetrapoda - Reptilia Reptiles development of a scaly skin to prevent water loss development of amniote egg that doesn’t have to be laid in water

Chordata - Chordate evolution - Vertebrates - craniates with a backbone Jawed vertebrates - Gnathostomes - Tetrapoda - Reptilia Reptiles development of a scaly skin to prevent water loss development of amniote egg that doesn’t have to be laid in water Salamander egg Reptile egg

Amniote Egg Amnionic sac – protects embryo Allantois – disposal sac for embryonic waste, works with chorion in gas exchange Chorion – with membrane of the allantois exchanges O2 and CO2 with the air Yolk sac – storage and transfer of nutrients to developing embryo

REPTILIA GROUPS

Next time: Reptiles Mammals