48
Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Embed Size (px)

Citation preview

Page 1: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Sharks, skates and rays

Placoid scales Ampullary organs

Chondrichthyes

Page 2: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Placoid scales and drag

Page 3: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

No swim bladder for buoyancy big liver loss of weight lift from tail, pectoral fins

Chondrichthyes

Page 4: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Heterocercal vs. Homocercal tails

Heterocercal

Homocercal

Page 5: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes
Page 6: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Teeth in shark originate from modified placoid scales

‘Denticles’

Enamel

Dentine

Page 7: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

DenticlesPlacoid scalesTeeth

Page 8: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Septal gill design

Chondrichthyes

Page 9: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes
Page 10: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Phylum Chordata Subphylum Urochordata (Tunicata) Subphylum CephalochordataCraniata group Subphylum Vertebrata

Superclass Agnatha Superclass Gnathostomata

Class PlacodermiClass ChondrichthyesClass AcanthodiiClass OsteichthyesClass AmphibiaClass ReptiliaClass MammaliaClass Aves

Page 11: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

“Bony fish”By far the most diverse class.

Swim bladder (or gas bladder) present in in most species

Osteichthyes

Page 12: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Swim bladder

Page 13: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Opercular gills - bony covering overlying gill slits

Page 14: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Actinopterygii Teleostei

Sarcopterygii Dipnoi Crossopterygii

Some major groupings in Osteichthyes

Page 15: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Actinopterygians - ray-finned fish dominant form presently fins move via muscles in body wall fins w/ Lepidotrichia

2 major groups:

Page 16: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Teleosts - diverse group of Actinopterygians

Recent radiation - 65 million years ago Has a derived swim bladder design

(detached from gut)

Actinopterygii

Page 17: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Sarcopterygians - fleshy-finned fish Thicker fins - muscles within fins Swim bladder connected to gut

(ancestral) Internal nostril (choana) first arose in

this group fossil sarcopterygian w/choana

Early choanates

Page 18: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Dipnoi - lungfish Paired lungs Survive in mud by breathing air. In warm waters - not as much

dissolved oxygen

Sarcopterygii

Page 19: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Crossopterygii - Several fossil forms with swim

bladders used as “lungs” One living - Coelacanth

Sarcopterygii

Page 20: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

CrossopterygiiHomologies with Amphibia

Bones in fins correspond to bones in early tetrapods

Labyrithodont teeth

Page 21: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Crossopterygian and Labyrinthodont skulls

Page 22: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes
Page 23: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Crossopterygian fish

Early tetrapod

Page 24: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Fossil organisms showing a fish/tetrapod transition

Tiktaalik roseae Acanthostega

“Labyrinthodont” group

Page 25: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Actinopterygii - Ray-finned Sacropterygii - fleshy-finned

Page 26: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Phylum Chordata Subphylum Urochordata (Tunicata) Subphylum CephalochordataCraniata group Subphylum Vertebrata

Superclass Agnatha Superclass Gnathostomata

Class PlacodermiClass ChondrichthyesClass AcanthodiiClass OsteichthyesClass AmphibiaClass ReptiliaClass MammaliaClass Aves

Tetrapods

Page 27: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

From water to land:

Page 28: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

“Problems”:Support - Air is a thinner medium.

From water to land:

Page 29: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

“Problems”:Support - Air is a thinner medium.Gas exchange - Oxygen in a different

state.

From water to land:

Page 30: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

“Problems”:Support - Air is a thinner medium.Gas exchange - Oxygen in a different

state.Temperature - Fluctuates more in air.

From water to land:

Page 31: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

“Problems”:Support - Air is a thinner medium.Gas exchange - Oxygen in a different

state.Temperature - Fluctuates more in air.Keeping moist - How to keep tissues,

eggs, young moist?

From water to land:

Page 32: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Fossil amphibians

Page 33: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes
Page 34: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Amphibia - have aquatic larval stage

Toads and Frogs (Anura) Salmanders (Urodela) Caecilians (Gymnophiona)

Page 35: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Phylum Chordata Subphylum Urochordata (Tunicata) Subphylum CephalochordataCraniata group Subphylum Vertebrata

Superclass Agnatha Superclass Gnathostomata

Class PlacodermiClass ChondrichthyesClass AcanthodiiClass OsteichthyesClass AmphibiaClass ReptiliaClass MammaliaClass Aves

TetrapodsAmniotes

Page 36: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Amniotes - have embryos with extra-embryonic membranes

amnion keeps water from leaving the egg or developing young.

Amniotes

Page 37: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Major living ‘reptile’ groups:

Lizards and snakes (Squamata) Crocodiles and alligators (Crocodilia) Turtles (Testudinata)

Page 38: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Most diverse class of tetrapods

Feathers modification of skin thermoregulation, flight

Aves

Page 39: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Microraptor gui

Page 40: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes
Page 41: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Puts particular requirements on

some physiological systems:

Circulatory, respiratory systems must be efficient and work at high rates

Endothermy

Page 42: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes
Page 43: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Defining characteristics:

Hair - for insulation, sensation.

Mammary glands

Other glands - sweat and sebaceous glands.

Mammalia

Page 44: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Via fossil evidence:

1. Three bones make up middle ear:malleus, incus, stapes

Distinguishing mammal from reptile fossils

Theraspid

Page 45: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

2. Lower jaw a single bone (dentary)

3. Jaw joint is articulation of dentary and squamosal bone.

Distinguishing mammal from reptile fossils

Page 46: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Major mammal groups:

Monotremes - oviparous

Page 47: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Therians - viviparous Marsupials - partial internal -

external development

Page 48: Sharks, skates and rays Placoid scales Ampullary organs Chondrichthyes

Therians - viviparous Placentals (eutherians) -

completely internal development - Most diverse