¿ 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 ?

The vertebrate story… There are over 57,000 living vertebrate species For every extant species 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 huge their heart is a big a small car Vertebrate lifestyle is energetically expensive… obtain energy as both carnivores and herbivores with many specializations in between

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

Amniotes , which also has two major groups: Sauropsids - 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)

¿How many species are there on planet Earth? 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…

Agnatha Extinct: Ostracoderms *Coverd 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 http://universe-review.ca/I10-27-jawlessfish.jpg

Agnatha 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 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

Agnathans are a Polyphyletic group! 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 branchial skeleton http://tolweb.org/Vertebrata

Hagfish (Myxinoidea) … Class - Myxini Order – Myxiniformes Extant Jawless fishes… Hagfish (Myxinoidea) … Class - Myxini Order – 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=g8pONkTyk2c http://www.youtube.com/watch?v=NYRr_MrjebA&NR=1

Hagfish (Myxinoidea) … Extant Jawless fishes… Hagfish (Myxinoidea) … They burrow and perhaps feed on soft-bodied worms etc. they encounter. Also scavenge and prey on fish Apparently 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

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

Hagfish (Myxinoidea) … 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 http://www.austmus.gov.au/fishes/fishfacts/fish/ecirrhatus6.htm Broad-gilled Hagfish

Hagfish (Myxinoidea) … 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.

Hagfish (Myxinoidea) … 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.

Hagfish (Myxinoidea) … 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.

Hagfish (Myxinoidea) … Extant Jawless fishes… http://www.daylife.com/photo/0e9DdRDaeV8qa 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/0g1T92TaxK623

Lamprey (Petromyzontoidea) … Class – Cephalaspidomorphi 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

Lamprey (Petromyzontoidea) … Extant Jawless fishes… Lamprey (Petromyzontoidea) … Petromyzon marinus Sea Lamprey

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

Lampreys (Petromyzontoidea) … 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

Lampreys (Petromyzontoidea) … 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

Lampreys (Petromyzontoidea) … 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!

Lampreys (Petromyzontoidea) … Extant Jawless fishes… Lampreys (Petromyzontoidea) …

Lampreys (Petromyzontoidea) … Extant Jawless fishes… Lampreys (Petromyzontoidea) …

Lampreys (Petromyzontoidea) … Extant Jawless fishes… Lampreys (Petromyzontoidea) …

Lampreys (Petromyzontoidea) … Extant Jawless fishes… Lampreys (Petromyzontoidea) …

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

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

Gnathostomes 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 http://sps.k12.ar.us/massengale/images/R-acanthodians.gif

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

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

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

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

Amphibia *Paraphyletic group… omitting amniote descendants *Extinct groups include Labrynthodonts (Ichthyostega) *Extant group (Lissamphibia) includes: Apoda (caecilians) Urodela (salamanders) Anura (frogs) 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

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

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

Mammalia Monotremata

Mammalia Marsupialia

Mammalia Insectivora

Mammalia Xenarthra

Mammalia Tubulidentata

Mammalia Pholidota

Mammalia Chiroptera

Mammalia Primates

Mammalia Lagomorpha

Mammalia Rodentia

Mammalia Carnivora

Mammalia Pinnipedia

Mammalia Perissodactyla

Mammalia Atriodactyla

Mammalia Hyracoidea

Mammalia Proboscidea

Mammalia Sirenia

Mammalia Cetacea