¿ What anatomical/physiological features distinguish vertebrates?

1. ¿ What anatomical/physiological features distinguish vertebrates? ¿ Who are vertebrates related to, and how are they related to each other ? ¿ In what ecosystems do vertebrates occur ? ¿ What are the roles of vertebrates in aquatic and terrestrial ecosystems ? ¿ How many different kinds or species of vertebrates are there ?

2. The vertebrate story… There are over 57,000 living vertebrate species For every extantspecies there were ~100 that are now extinct Vertebrates are found in almost all environments on earth, from ocean depth to highest mountains and from pole to pole Vertebrates range in size from tiny fish, amphibians and reptiles small enough to fit on a coin, to blue whales who are so hugetheir heart is a big a small car Vertebrate lifestyle is energetically expensive… obtain energy as both carnivores and herbivores with many specializations in between

3. The vertebrate story… • Two major groups of vertebrates • 1) Non-amniotes: • A-gnathans(Myxinoidea&Petromyzontoidea)(~100 species) • Chondr-ichthians(~1,000 species) • Osteichthians(~27,000 species) • Amphibians(~6,400 species)

4. The vertebrate story… • Two major groups of vertebrates… • Amniotes , which also has two major groups: • Sauropsids - • Testudinians(~300 species) • Lepido-saurians(~8,000 species) • Crocodilians(~25 species) • Avians(~9,700 species) Synapsids – Mammalians (~4,800 species)

5. The vertebrate story… New species… ¿How many species are there on planet Earth? Estimates vary by an order of magnitude! Thousands of species described annually Most are small and of “other” kingdoms… still some vertebrates being described. Examples…

7. Extinct: Ostracoderms *Covered by bony armor *Mostly small fish 2cm (some up to 2m) *Small mouth openings *4 openings on dorsal surface of head *Extinct after abundance of jawed fishes on the scene Agnatha http://universe-review.ca/I10-27-jawlessfish.jpg

8. Extant: “Cyclostomes”Hagfish and Lamprey *Are not as closely related as might appear *Hagfish are scavengers that lack the rasping denticles of lamprey *Most Lamprey are parasitic Agnatha http://www.exploretheabyss.com/photo/gallery/gallery/ds_trawl/images/HagfishLR.jpg http://www.glaucus.org.uk/sea-lamprey-sucker-RL.jpg http://www.nwrc.usgs.gov/world/images/lamprey.jpg

9. Extant Jawless fishes… • Agnathans are a Polyphyletic group! • Super class Agnatha (oldest craniates in fossil record) Cambrian or earlier • Most abundant in Silurian and lower Devonian • Fossil fish small <15cm (although some up to 2m) • Sucking or scooping feeding mechanism • Conodonts resemble hagfish (Cambrian to Triassic) • All gill tissue is endodermal in origin • Gill structures, arteries, nerves etc. internal to branchialskeleton http://tolweb.org/Vertebrata

10. Extant Jawless fishes… • Hagfish (Myxinoidea) … • Class -MyxiniOrder –Myxiniformes • Family – Myxinidae • Genera – 6 from mostly temperate waters • Species -> 40 with Pacific and Atlantic Hagfish most well known. • At least one fossil representative from Carboniferous that resembles modern species. • Only occur in marine habitats • Live on soft bottoms of mud, • silt or clay usually from 25 – 600m deep. http://www.bio.uio.no/akv/english/research/mzk/benthos_pictures.html http://www.youtube.com/watch?v=NYRr_MrjebA&NR=1 http://www.youtube.com/watch?v=g8pONkTyk2c

11. Extant Jawless fishes… • Hagfish (Myxinoidea) … • They burrow and perhaps feed on soft-bodied worms etc. they encounter. • Also scavenge and prey on fishApparently good sense of smell,as they quickly find netted fish. • Unique “knotting” technique allows • them to pull meat from carcass. • Eversion and retraction of teeth • on each side of mouth • pull off/in food http://sophont.blogspot.com/2004_02_01_archive.html http://bakkouz.net/pix/Hagfish.jpg

12. Extant Jawless fishes… • Hagfish (Myxinoidea) … • Eyes degenerate and covered by skin • Large tentacles surround nasal opening and mouth • Probably lack a larval stage http://www.uoregon.edu/~joet/Pictures-Pages/Image5.html http://a.abcnews.com/Technology/AmazingAnimals/popup?id=4958186&contentIndex=1&page=6&start=false http://www.gma.org/fogm/myxine_glutinosa.htm

13. Extant Jawless fishes… • Hagfish (Myxinoidea) … • 5 to 15 pairs of gills (depending on species) • Some species have branchial ducts that exit via a single tube and external opening Broad-gilled Hagfish http://www.austmus.gov.au/fishes/fishfacts/fish/ecirrhatus5.htm Broad-gilled Hagfish http://www.austmus.gov.au/fishes/fishfacts/fish/ecirrhatus6.htm

14. Extant Jawless fishes… • Hagfish (Myxinoidea) … • Cartilaginous skeleton not well developed…* No vertebrae* Only a membranous roof of the skull • 1 semicircular canal on each side of head (Lamprey have 2 and other vertebrates have 3) • In addition to primitive heart… they also have contractile vascular regions in:* Tail* Cardinal vein • * Portal vein • Have red blood cells like other vertebrates… but only one type of WBC.

15. Extant Jawless fishes… • Hagfish (Myxinoidea) … • Females outnumber males 100 to 1 • Thought at first to be hemaphroditic • Almost nothing known of their reproductive biology! • Recent studies have verified the presence of neural crest cells.

16. Extant Jawless fishes… • Hagfish (Myxinoidea) … • Well known for a defensive mechanism… SLIME! • Abundant mucous glands secreting mucus and coiled proteins • Proteins straighten in water and trap mucus close to hagfishes body • After danger has left, hagfish ties a knot in tail and pulls it towards its head “squeegie-ing” off the slime.

17. Extant Jawless fishes… • Hagfish (Myxinoidea) … • Some commercial use in Asia as source • for leather and meat. • Can cause some • Economic loss to • commercial fisheries • when able to • access fish • caught in gill nets • and/or long lines • “Human exploitation • Of natural resources, • such as fisheries, typically depletes • stocks because no attention is given • to the biology of the resource and its • renewable, sustainable characteristics. • For example, we do not know how long • Hagfish live; how old they are when • they first begin to reproduce; exactly how, when or where they breed; where the youngest juveniles live; what are the diets and energy requirements of free-living hagfishes; or virtually any of the other information needed for good management. As a result, eel-skin wallets will probably become as rare as items made of whalebone , tortoise shell and ivory. “(Pough et al . 2009, pg. 59) http://www.daylife.com/photo/0e9DdRDaeV8qa http://www.daylife.com/photo/0g1T92TaxK623

18. Extant Jawless fishes… • Lamprey (Petromyzontoidea) … • Class –Cephalaspidomorphi • Order –Petromyzontiformes / (Hyperoartia) • Family – Petromyzontidae • Genera – 10 • Species -~ 40 with Petromyzon sp. and Lampetra sp. most well known. • Superficially resemble Hagfish, but differ in several important ways including vertebrae • Unique in having a nasal opening (single) that leads to the pituitary gland. http://www.gma.org/fogm/Petromyzon_marinus.htm

19. Extant Jawless fishes… • Lamprey (Petromyzontoidea) … • Petromyzonmarinus Sea Lamprey

20. Extant Jawless fishes… • Lampreys (Petromyzontoidea) … • Most species areparasitic • Use hornified “teeth” • on the surface of theoral hood and tongue • Can have a negative • Impact on game • and commercial • fisheries http://www.gma.org/fogm/Petromyzon_marinus.htm http://en.wikipedia.org/wiki/File:Boca_de_lamprea.1_-_Aquarium_Finisterrae.JPG http://www.biology.duke.edu/bio217/2005/ncy/sea%20lamprey.html

21. Extant Jawless fishes… • Lampreys (Petromyzontoidea) … • Lampreys have 7 pairs of gill pouches • Do not typically use flow-through ventilation • Rather, they use tidal ventilation http://www.rsc.org/chemistryworld/News/2005/September/03100501.asp

22. Extant Jawless fishes… • Lampreys (Petromyzontoidea) … • Nearly all species are anadromous • Anadromous species that grow in adult form in the sea are the largest (up to 1m) • A small parasitic species (Lampetra minima) was full grown at less than 10 cm (now extinct) • Spawn in streams • Lay 100,000s of eggs http://oregonstate.edu/dept/ODFW/NativeFish/Lamprey.htm

23. Extant Jawless fishes… • Lampreys (Petromyzontoidea) … • Larval lamprey are called ammocoetes • Live in gravel beds filtering plankton and organic debris for 3-7 years • Metamorphose and then begin journey to sea or other major water basin where they will grow and mature. • Usually live as adults for less than 2 years. • They migrate back up to their hatching grounds (now spawning grounds) • Mate and then die!

24. Extant Jawless fishes… • Lampreys (Petromyzontoidea) …

25. Extant Jawless fishes… • Lampreys (Petromyzontoidea) …

26. Extant Jawless fishes… • Lampreys (Petromyzontoidea) …

27. Extant Jawless fishes… • Lampreys (Petromyzontoidea) …

28. 3 groups appeared in the Paleozoic: 1) Placoderms(ex. Arthrodires) had large boney plates and paired fins Gnathostomes http://www.noaca.org/earlgeo.gif http://www.cnrs.fr/cw/dossiers/dosevol/imgArt/dioram/PaleozoDevon/Zimg/dicksonosteus.jpg

29. 3 groups appeared in the Paleozoic: 2) Chondrichthyans (cartilagenous fishes)*Includes sharks, rays, skates, and ratfish *Cartilaginous skeletons *Many with placoids *No bony operculum Gnathostomes http://www.lifeglobe.com/images/product/Sharks/sharks04_r2_c2.jpg http://www.pangaeadesigns.com/_graphics/page/fish/large/ratfish.jpg

30. 3 groups appeared in the Paleozoic: 3) Teleostomes (spiny and bony fishes) *Acanthodians are (spiny fishes) are extinct *Had skeleton of bone and cartilage *Had an operculum Gnathostomes http://sps.k12.ar.us/massengale/images/R-acanthodians.gif

31. Shared ancestors with tetrapods Have an air sac Dermal bone Paired fins… either ray finned (actinopterygii) or fleshy finned (sarcopterygii) Osteichthyans http://www.paleodirect.org/fg009.htm

32. Basal groups include Sturgeon and Paddlefish Actinopterygii http://www.hellscanyonsportfishing.com/images/sturgeon%20pictures/Kevin%20&%20Sturgeon%202.jpg http://www.digimorph.org/specimens/Polypterus_senegalus/whole/specimen.jpg

33. Advanced groups include Gars, Bowfins and Teleosts(most other bony fish) Actinopterygii http://www.sdafs.org/laafs/Amazing%20Fish%20Pictures/Big%20Alligator%20Gar%2009-03.JPG

34. Have fleshy lobed fins, internal nares and a bony operculum 2 major clades: Actinistians, extinct except “coelocanths” Rhipidistians(and dipnoi)“lungfish” Sarcopterygii http://kentsimmons.uwinnipeg.ca/16cm05/1116/34-14-Coelocanth.jpg http://www.bertsgeschiedenissite.nl/geschiedenis%20aarde/lungfish.jpg

35. *Paraphyletic group… omitting amniote descendants *Extinct groups include Labrynthodonts (Ichthyostega) *Extant group (Lissamphibia) includes: Apoda (caecilians) Urodela (salamanders) Anura (frogs) Amphibia http://www.bbc.co.uk/radio4/science/media/Btaitanus-PC1b.jpg http://news.siu.edu/news/May05/images/salamander.jpg http://www.yesnet.yk.ca/schools/wes/webquests_themes/frogs_theme/frogs_K/frog_species/barred/images/barred_leaf_frog_jpg.jpg

36. Group includes Reptiles and Synapsids Reptilia (paraphyletic) Chelonia (testudinea) “turtles” Rhynchocephalians “tuatara” Squamates “lizards, snakes etc.” Crocodylians “crocodiles” etc. Aves “birds” Amniotes

37. Amniotes with synapsid skull, hair, mammary glands & nipples (most) Synapsids

38. Monotremata Mammalia

39. Marsupialia Mammalia

40. Insectivora Mammalia

41. Xenarthra Mammalia

42. Tubulidentata Mammalia

43. Pholidota Mammalia

44. Chiroptera Mammalia

45. Primates Mammalia

46. Lagomorpha Mammalia

47. Rodentia Mammalia

48. Carnivora Mammalia

49. Pinnipedia Mammalia

50. Perissodactyla Mammalia