The Biology of Amphibians @ Agnes Scott College Mark Mandica Executive Director The Amphibian Foundation [email protected] 678 379 TOAD (8623) Phyllomedusidae: Agalychnis moreletii 1.2: Introduction of Amphibians Centrolenidae: Hyalinobatrachium valeroi Evolution of Amphibians † † † † Actinopterygian Coelacanth, Tetrapodomorpha †Amniota *Gerobatrachus (Ray-fin Fishes) Lungfish (stem-tetrapods) (Reptiles, Mammals)Lepospondyls † (’frogomander’) Eocaecilia GymnophionaKaraurus Caudata Triadobatrachus Anura (including Apoda Urodela Prosalirus †) Salientia Batrachia Lissamphibia *Gerobatrachus may be the sister taxon Temnospondyls † to Batrachia Tetrapods Osteichthyes Sarcopterygian (Bony Fishes) (Lobe-fin Fishes) Amphibian Reign Time Period Devonian Carboniferus Permian Triassic Jurassic Cretaceous Millions of Years Ago (420 MYA) (350 MYA) (300 MYA) (250 MYA) (200 MYA) (150-65 MYA) Present Day resembles Plate Tectonics Gondwana + Laurussia Pangea Pangea Pangea begins to break Pangea breaks present day The Biology of Amphibians amphibbio.amphibianfoundation.org Plate Tectonics Evolution of Amphibians † † † † Actinopterygian Coelacanth, Tetrapodomorpha †Amniota *Gerobatrachus (Ray-fin Fishes) Lungfish (stem-tetrapods) (Reptiles, Mammals)Lepospondyls † (’frogomander’) Eocaecilia GymnophionaKaraurus Caudata Triadobatrachus Anura (including Apoda Urodela Prosalirus †) Salientia Batrachia Lissamphibia *Gerobatrachus may be the sister taxon Temnospondyls † to Batrachia Tetrapods Osteichthyes Sarcopterygian (Bony Fishes) (Lobe-fin Fishes) Amphibian Reign Time Period Devonian Carboniferus Permian Triassic Jurassic Cretaceous Millions of Years Ago (420 MYA) (350 MYA) (300 MYA) (250 MYA) (200 MYA) (150-65 MYA) Present Day resembles Plate Tectonics Gondwana + Laurussia Pangea Pangea Pangea begins to break Pangea breaks present day The Biology of Amphibians amphibbio.amphibianfoundation.org Evolution of Amphibians † † † † Actinopterygian Coelacanth, Tetrapodomorpha †Amniota *Gerobatrachus (Ray-fin Fishes) Lungfish (stem-tetrapods) (Reptiles, Mammals)Lepospondyls † (’frogomander’) Eocaecilia GymnophionaKaraurus Caudata Triadobatrachus Anura (including Apoda Urodela Prosalirus †) Salientia Batrachia Lissamphibia *Gerobatrachus may be the sister taxon Temnospondyls † to Batrachia Tetrapods Osteichthyes Sarcopterygian (Bony Fishes) (Lobe-fin Fishes) Amphibian Reign Time Period Devonian Carboniferus Permian Triassic Jurassic Cretaceous Millions of Years Ago (420 MYA) (350 MYA) (300 MYA) (250 MYA) (200 MYA) (150-65 MYA) Present Day resembles Plate Tectonics Gondwana + Laurussia Pangea Pangea Pangea begins to break Pangea breaks present day The Biology of Amphibians amphibbio.amphibianfoundation.org Phylogenetic tree (or cladogram) clade = monophyletic A group of organisms which includes the most recent common ancestor of all of its members and all of the descendants of that most recent common ancestor paraphyletic A group of organisms which includes the most recent common ancestor of all of its members, but not all of the descendants of that most recent common ancestor X polyphyletic A group of organisms which does not include the most recent common ancestor of those organisms; the ancestor does not possess the character shared by members of the group. node The point at which the branch of a phylogenetic tree (or cladogram) intersects or terminates. phylogeny -- The evolutionary relationships among organisms; the patterns of lineage branching produced by the true evolutionary history of the organisms being considered. Phylogenetic tree (or cladogram) derived Refers to a character or feature found within a sister group single lineage of a larger group; it is not shared The two clades resulting from the 2 with all organisms in the larger group. Derived splitting of a single lineage characters are used to infer evolutionary ‘E’ (node 2) is the ‘sister group’ to node 1 relationships, as derived characters evolved after primitive characters (eg: node 2) 1 apomorphy pleisiomorphy A novel derived evolutionary trait that is A primitive character state for the unique to a particular species taxa under consideration. synapomorphy A character which is derived, and because it basal is shared by the taxa under consideration, is The earliest diverging group used to infer common ancestry within a clade (eg: node 1) systematics -- Field of biology that deals with the diversity of life. Systematics is usually divided into the two areas of phylogenetics and taxonomy. Evolution of Amphibians † † † † Actinopterygian Coelacanth, Tetrapodomorpha †Amniota *Gerobatrachus (Ray-fin Fishes) Lungfish (stem-tetrapods) (Reptiles, Mammals)Lepospondyls † (’frogomander’) Eocaecilia GymnophionaKaraurus Caudata Triadobatrachus Anura (including Apoda Urodela Prosalirus †) Salientia Batrachia Lissamphibia *Gerobatrachus may be the sister taxon Temnospondyls † to Batrachia Tetrapods Osteichthyes Sarcopterygian (Bony Fishes) (Lobe-fin Fishes) Amphibian Reign Time Period Devonian Carboniferus Permian Triassic Jurassic Cretaceous Millions of Years Ago (420 MYA) (350 MYA) (300 MYA) (250 MYA) (200 MYA) (150-65 MYA) Present Day resembles Plate Tectonics Gondwana + Laurussia Pangea Pangea Pangea begins to break Pangea breaks present day The Biology of Amphibians amphibbio.amphibianfoundation.org Actinopterygii: Ray-finned Fishes Oncorhynchus clarkii lewisi Evolution of Amphibians † † † † Actinopterygian Coelacanth, Tetrapodomorpha †Amniota *Gerobatrachus (Ray-fin Fishes) Lungfish (stem-tetrapods) (Reptiles, Mammals)Lepospondyls † (’frogomander’) Eocaecilia GymnophionaKaraurus Caudata Triadobatrachus Anura (including Apoda Urodela Prosalirus †) Salientia Batrachia Lissamphibia *Gerobatrachus may be the sister taxon Temnospondyls † to Batrachia Tetrapods Osteichthyes Sarcopterygian (Bony Fishes) (Lobe-fin Fishes) Amphibian Reign Time Period Devonian Carboniferus Permian Triassic Jurassic Cretaceous Millions of Years Ago (420 MYA) (350 MYA) (300 MYA) (250 MYA) (200 MYA) (150-65 MYA) Present Day resembles Plate Tectonics Gondwana + Laurussia Pangea Pangea Pangea begins to break Pangea breaks present day The Biology of Amphibians amphibbio.amphibianfoundation.org Sarcopterygii: Lobe-finned Fishes Bichir Coelacanth Lungfish Sarcopterygii: Eusthenopteron † Tetrapodomorph fish Late Devonian period, about 385 million years ago Sarcopterygii: Panderichthys † Tetrapodomorph fish Late Devonian period, about 380 million years ago Sarcopterygii: Tiktaalik † Tetrapodomorph fish Late Devonian period, about 375 million years ago Preparations for Terrestrial Life Why would Devonian vertebrates want to leave the water? Preparations for Terrestrial Life Pre-adaptations What types of changes would need to occur to support life on land? Preparations for Terrestrial Life Pre-adaptations Respiration Gills ————> Lungs Preparations for Terrestrial Life Pre-adaptations Gravitational Support Bending of wrists and ankles Well developed ribs Weight bearing bones Preparations for Terrestrial Life Pre-adaptations Sensory Perception Smells, sights and sounds are transmitted differently in air and water Preparations for Terrestrial Life Pre-adaptations Larval Development A free-swimming aquatic larval stage metamorphoses into a terrestrial adult Preparations for Terrestrial Life Pre-adaptations Neck Mobility Cervical vertebrae provide flexion for locating prey and predators Preparations for Terrestrial Life Pre-adaptations Hindlimb Locomotion Development of sacrum and sacral vertebrae Preparations for Terrestrial Life Pre-adaptations Feeding Changes in feeding mechanism from suction feeding to biting Evolution of Amphibians † † † † Actinopterygian Coelacanth, Tetrapodomorpha †Amniota *Gerobatrachus (Ray-fin Fishes) Lungfish (stem-tetrapods) (Reptiles, Mammals)Lepospondyls † (’frogomander’) Eocaecilia GymnophionaKaraurus Caudata Triadobatrachus Anura (including Apoda Urodela Prosalirus †) Salientia Batrachia Lissamphibia *Gerobatrachus may be the sister taxon Temnospondyls † to Batrachia Tetrapods Osteichthyes Sarcopterygian (Bony Fishes) (Lobe-fin Fishes) Amphibian Reign Time Period Devonian Carboniferus Permian Triassic Jurassic Cretaceous Millions of Years Ago (420 MYA) (350 MYA) (300 MYA) (250 MYA) (200 MYA) (150-65 MYA) Present Day resembles Plate Tectonics Gondwana + Laurussia Pangea Pangea Pangea begins to break Pangea breaks present day The Biology of Amphibians amphibbio.amphibianfoundation.org Tetrapodomorpha: Acanthostega † Late Devonian period, about 365 million years ago Tetrapodomorpha: Ichthyostega † Late Devonian period, about 365 million years ago Evolution of Amphibians † † † † Actinopterygian Coelacanth, Tetrapodomorpha †Amniota *Gerobatrachus (Ray-fin Fishes) Lungfish (stem-tetrapods) (Reptiles, Mammals)Lepospondyls † (’frogomander’) Eocaecilia GymnophionaKaraurus Caudata Triadobatrachus Anura (including Apoda Urodela Prosalirus †) Salientia Batrachia Lissamphibia *Gerobatrachus may be the sister taxon Temnospondyls † to Batrachia Tetrapods Osteichthyes Sarcopterygian (Bony Fishes) (Lobe-fin Fishes) Amphibian Reign Time Period Devonian Carboniferus Permian Triassic Jurassic Cretaceous Millions of Years Ago (420 MYA) (350 MYA) (300 MYA) (250 MYA) (200 MYA) (150-65 MYA) Present Day resembles Plate Tectonics Gondwana + Laurussia Pangea Pangea Pangea begins to break Pangea breaks present day The Biology of Amphibians amphibbio.amphibianfoundation.org Lepospondyl: Diplocaulus † Permian period, about 300 million years ago Lepospondyl: Diplocaulus † Permian period, about 300 million years ago Evolution of Amphibians † † †