参考教程案例沉19lecture invasion of land ii amphibians.pptx

Invasion of Land II: Devonian Forests and 4 Legs on Land!/watch?v=B9h1tR42QYAfeature=player_embedded/watch?v=B9h1tR42QYAfeature=player_embedded#!LycopsidsClub mossesArchiopterisA Devonian tree that grew up to 10 m tallLarge spore bearing tree.Devonian Land PlantsAdaptations that led to the development of seeds:Hetrospory (Progymnosperms)Hetrospory: 2 types of spores produced –Larger female spore with a food store, and a smaller male spore. Exhibited by fossil spores from Archiopteris.Widely thought to be precursor to seeds/ pollen developed in later gymnosperms.Devonian Gymnosperms and forestsThe earliest seed plants:Devonian seed fernsRuncaria Why was the evolution of seeds important? ArchiopterisWith Rhipidistian fish shown in adjacent lakeMiddle Devonian forest with Protolepidodendron (an early lycopsid)Calamophyton, an early form of horsetail rush, and Esopermatopteris, fernsFossil Devonian Forest (Esopermatopteris trunks) In Gilboa, upstate New York When did vertebrates first venture onto land? What type of animal do you think they were?How did they get there? Amphibians(4 legs-tetrapods)!They evolved from fish!OsteichtysA story of fish evolution into lakes and eventually venturing onto land. SarcopterygiActinopterygiEarly Jawless fish: Ostracoderms (Ord-Dev)Jawed fish with external Plated Armor: Placoderms (Sil-Dev), Acatnthoderms (Silurian-Perm).Cartilaginous fish, sharks and rays: Chondrichthys (Dev-R). “Modern” bony fish with complex bony skeleton: Osteichthys (Dev-R). Osteichthys diverged into the ray finned fish (Actinopterygi) + the lobe finned fish, with lungs (Sarcopterygi) including Rhipidstians (amphibian ancestors)Rhipidistian fish (Crossopterygians) : A lobe finned fish considered to be the ancestors ofAmphibiansOsteolepisRhipidistian fishearly AmphibianHigh similarity in bone arrangement of skull and limbsEusthenopteronGould p. 80Why would fish/ amphibians venture onto land: Old idea: To escape drying lakes!In other words they evolved to walk