¿ What anatomical/physiological
features distinguish vertebrates?
¿ In what ecosystems do
vertebrates occur ?
¿ Who are
vertebrates related
to, and how are
they related to each
other ?
¿ 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
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)
The vertebrate story…
Two major groups of vertebrates…
2) Amniotes , which also has two major groups:
Sauropsids Synapsids –
Testudinians
Mammalians
(~300 species)
(~4,800 species)
Lepido-saurians
(~8,000 species)
Crocodilians
(~25 species)
Avians
(~9,700 species)
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
*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
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
http://www.exploretheabyss.com/photo/gallery/gallery/
ds_trawl/images/HagfishLR.jpg
*Most Lamprey are
parasitic
http://www.glaucus.org.uk/sea-lamprey-sucker-RL.jpg
http://www.nwrc.usgs.gov/world/images/lamprey.jpg
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
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
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
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
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
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.
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.
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.
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
http://www.daylife.com/photo/0e9DdRDaeV8
qa
“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, eelskin 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
Extant Jawless fishes…
Lamprey (Petromyzontoidea) …
Class – Cephalaspidomorphi
Order – Petromyzontiformes /
(Hyperoartia)
Family – Petromyzontidae
Genera – 10
Species - ~ 40 with
http://www.gma.org/fogm/Petromyzon_marinus.htm
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.
Extant Jawless fishes…
Lamprey (Petromyzontoidea) …
Petromyzon marinus Sea Lamprey
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://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
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
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
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!
Extant Jawless fishes…
Lampreys (Petromyzontoidea) …
Extant Jawless fishes…
Lampreys (Petromyzontoidea) …
Extant Jawless fishes…
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/Shark
s/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/imag
es/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%2
0Alligator%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/16cm0
5/1116/34-14-Coelocanth.jpg
http://www.bertsgeschiedenissite.nl/geschiedenis%20aarde/lun
gfish.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/Btai
tanus-PC1b.jpg
http://news.siu.edu/news/May05/images/salamande
r.jpg
http://www.yesnet.yk.ca/schools/wes/webquests_themes/frog
s_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
• Cloaca/Eggs
• No front teeth (or no teeth at all)
• Opposable thumbs
• Peg-like teeth (African)
• Pouch
• Aquatic ungulates without hindlimbs
• Aquatic with nostrils on top of
head
• Canine with fins/terrestrial birth
• Growing incisors/hoof-like nails
• Incisors form tusks
• Scaly
• Single pair of growing incisors
• Smooth cerebral cortex/sharp teeth
• Ungulates with even #
• Two pairs of incisors (only central
growing)
• Wings
toes/paraxonic foot
• Ungulates with odd # toes
(usually)/mesaxonic foot
• Well developed canines