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Vertebrate Evolution (PDF)

Vertebrate Evolution (PDF)


Torsten Bernhardt Redpath Museum, McGill University

This teaching was made possible with funding from the PromoScience programme of NSERC.

© McGill University 2010 History of the Earth

Origins of Origins of Bacteria

4.6 3.8-3.5 1.5 0.542 0 (Billions of )

(Millions of years) F5EB3891.jpg 004 - - media/54/4054 day/20060514 - - 2.web.britannica.com/eb - http://associationpourlasanteetlenvironnement.skynetblogs.be/ archive

Pikaia http://media (sea squirts) The First ? 02.jpg - dinosaurios - los de - - antes - http://permian.files.wordpress.com/2007/05/vida

Haikouichthys Agnathans: Jawless Fish (i)

Ostracoderms -armoured, jawless fish -used only for -no paired , so probably poor swimmers

Endeiolepis aneri Agnathans: Jawless Fish (ii) http://www.ne.jp/asahi/fragi/ragi/gallery/.html Cephalaspis

Ostracoderms went extinct in the , most likely due to the placoderms (who we’ll get to in a minute…) Agnathans: Jawless Fish (iii) http://www.utsc.utoronto.ca/~youson/images/.jpg

A modern agnathan: the lamprey Placoderms: Evolve (i)

-Still armoured -Jaws are a major advantage -First live -Paired fins http://www.pangaeadesigns.com/_gra phics/page/retail/large/bothriolepis.jpg

Bothriolepis Placoderms: Jaws Evolve (ii) http://www.dinotime.de/pictures/dunkleosteus.jpg

Dunkleosteus http://www.nmnh.si.edu/rtp/students/2006/images/paleo_day72.jpg

No teeth Cartilaginous Fish () (i)

-, skates, rays, chimeras Fish/chimaera_fish1.jpg http://www.mcaorals.co.uk/Photos/Deep%20Sea%20 - is made of instead of -Don’t fossilize well -Are thought to have evolved from placoderms 1.jpg - - white - Chimera http://www.divephotoguide.com/user/181/gallery/183/ http://templecuttingedge.files.wordpress.com/2009/06/great Cartilaginous Fish (Chondrichthyes) (ii) http://www.karencarr.com http://data3.blog.de/media/606/2129606_fb5a2adfe5_m.jpeg Stethacanthus Megalodon (~1.5 mya) (~360 Mya) Bony Fish () http://home - fish.jpg - store.co.uk/wp - content/uploads/2009/01/beta - - http://ricomoss.files.wordpress.com/2009/04/big fish - pictures.jpg Bony Fish – Ray-finned Fish ()

-25 000 , 99% of all fish today clown wallpapers.com/wallpapers/iphone - http://www.free - -Fins are supported by bony rays fish.jpg - mobile - wallpaper - Clown fish http://www.gnb.ca/0078/Hey_kids/images/BrookTrout.jpg Brook Homalacanthus Bony Fish – Lobe-finned Fish () images/.jpg - http://www.itsnature.org/Sea/images/article Coelacanth

-Fins have and muscle -Live on the bottom -Not especially diverse, as fish From Fish to

We think that amphibians evolved from sarcopterygian (lobe-finned) fish. Why is this?

One group of sarcopterygians, the osteolepiforms, had that led to an opening in the roof of its . This allowed air to pass into the mouth and then to paired swim bladders (similar to our ).

Lungfish, which are modern sarcopterygians, can crawl over land from one to another.

The sturdy fins of the sarcopterygians have bones much like those in our limbs. Other anatomical features, such as bones and teeth, also point to a relationship. From Fish to Amphibians nn.jpg http://higheredbcs.wiley.com/legacy/college/levin/0 - 471697435/chap_tut/images/nw0276 (left) and lobe-finned fish (right) http://www.hmnh.org/galleries /deadanimalblog/pf_tiktaalik.j pg

Early amphibians had as many as eight ; this was eventually reduced to five, or four Amphibians

-Early amphibians didn’t look like modern amphibians -Three-chambered -Had lungs, but also breathed through their http://www.foundalis.com/bio/cre/Icht hyostega.jpg -Were tied to water for -Dominant predators in the

http://darwiniana.org/acanthostega1.jpg Acanthostega http://dic.academic.ru/pictures/wiki/file s/101/eryops1db.jpg

Outer envelope L.gif Amphibian - AmnioticEgg

Inner envelope 19 - - http://kentsimmons.uwinnipeg.ca/16cm05/1116/34 http://en.wikipedia.org/wiki/Fil e:ChroniosuchusDB126.jpg Chroniosuchus, which may be an egg ancestor of amniotes

-Amniotes’ allowed them to reproduce away from water and expand to drier areas -They diverged into two lineages: one would eventually become , the other would become and -like reptiles () http://9thestate.com/images/gorgonopsid.jpg http://lesdinos.free.fr/dimetrodon.jpg

Dimetrodon Gorgonopsids

-Ancestors of true mammals -Regulated their temperature -Different types of teeth -Very successful until the end of the The Permian -The most severe in the Earth’s history -May be related to the Siberian Traps, the largest volcanic eruptions on Earth -96% of species in the go extinct, 70% of on land go extinct, 99.5% of all living creatures die -The mammal-like reptiles are severely affected http://www.lpi.usra.edu/education/timeline/gallery/images/053.jpg ! Reptiles views/1519/11653653.JPG http://www.dkimages.com/discover/pre -Many different groups -Scales, “3.5”-chambered heart -Almost all lay eggs -Extremely successful in the Mesozoic (which is known as the Age of Reptiles) Scutosaurus aures/Coelurosauravus.jpg http://mrugala.net/Nature/Animaux/Dinos http://www.kidsdinos.com/images/dino saurs/Mesosaurus1139704078.jpg

Mesosaurus, one of the Coelurosauravus, a first reptiles to return to gliding the sea Crurotarsi

-The group that today includes -Ruled the world in the , content/uploads/.jpg after the mammal–like reptiles were severely affected by the Permian extinction - http://www.cryptomundo.com/wp -Were themselves severely affected by the extinction Postosuchus event at the end of the Triassic Other Reptiles s/Tokay_Gecko.jpg http://petzotics.com/Lizards%20Image .jpg - sea http://naturescrusaders.files.wordpress.com/2009/02/gex_gr een - Green http://mudpuddle.files.wordpress.com/ 2009/02/henry.jpg http://naturescrusaders.files.wordpress.com/2009/04/rhabdo phis_tigrinus_06toad.jpg Tuatara

-Were around for 160 million years -May have been warm blooded -Two groups, based on structure -Advanced features – bones,

Triceratops Gorgosaurus Dinosaurs http://bydirigible.files.wordpress.com/2008/05/dinosaurs.jpg http://sciencejunkies.com/media//2009/03/blue_whale_size_comparison.gif Not Just Dinosaurs! (i) http://www.flashweb.gr/turtle2008/photos/arch.jpg http://archeowiesci.files.wordpress.com/20 07/11/sarcosuchus_and_nigersaurus.jpg

Crocodylimorphs picture.jpg - snake - biggest -

http://blogs.nationalgeographic.com/blogs/news/chi efeditor/world%27s Tuatara Not Just Dinosaurs! (ii) - http://www005.upp.so net.ne.jp/JurassicGallery/.jpg Ichthyosaurs http://www.linternaute.com/science/biologie/diaporam as/05/dinosaures/images/.jpg resFromTheDeep/CreaturesIMAGES/Plesiosaur_4_large.jpg http://www.discoverynews.us/DISCOVERY%20MUSEUM/Creatu

Pterosaurs - the first flying vertebrates http://www.search4dinosaurs.com/miller_mosasaur.jpg Plesiosaurs True Mammals

-Evolved from the synapsids (mammal-like reptiles) -Vaguely -like, small -Showed up not too long after the dinosaurs -Didn’t amount to much in the Mesozoic; lawnmower ecology http://piclib.nhm.ac.uk/piclib/webimages/0/1000/400/1461_med.jpg Birds

-Evolved from dinosaurs; specifically, the -eating deinonychosaurs, which includes Dromaeosaurus -Are technically dinosaurs http://centroufologicotaranto.files.wordpress.com/2009/10/archaeopteryx.jpg -Feathers evolved before birds did; T. rex may have been fuzzy -May have outcompeted the

- and helped drive them to extinction -The second group to missouri.jpg - http://desireestanley.files.wordpress.com/2009/03/blue Extinction http://life7.beyondgenes.com/images115/theend.JPG

-Ends the reign of the dinosaurs -Flying and swimming reptiles also go extinct -Many other groups suffer as well -Mammals step into the empty niches ! Mammals Take Over (i) umb/7/7a/Panochthus_frenzelianus.jpg/800px http://upload.wikimedia.org/wikipedia/commons/th Panochthus_frenzelianus.jpg - http://s3.amazonaws.com/lcp/first_corner_of_a nita_bokeron/myfiles/elephant.indricotherium.h uman.jpg Indricotherium Glyptodont eptictidium_1.jpg http://www.pts.org.tw/~web02/beasts/factfiles/primary_ff_displays/l http://hiddenway.tripod.com/images/creatures/smilodon.jpg http://www.bbc.co.uk/science/seamonsters/factfile s/images/arsinoitherium1.jpg Arsinoitherium Saber-toothed Leptictidium Mammals Take Over (ii) http://www.treehugger.com/bat - organic - coffee - 001.jpg

Bat content/uploads/2009/03/humpback_whale.jpg - sounds/letter http://www.dumbaaldum.org/images/pic - h/hand.jpg http://fascinatingly.com/wp Humpback -