Vertebrate Chordates

1. Vertebrate
Evolution and
Diversity
Lauren Moon, Reid
Merriken, Bobby Hix
https://daymondg.files.wordpress.com/2014/04/i-got-your-back.jpg

2. ● The chordata phylum is the most well known phylum because it includes
humans and other vertebrates (and some invertebrates)
● Most evolved phylum of animals
● It is characterized by the development of certain structures present at
some point during their lifetime
● They possess a notochord, a hollow dorsal nerve cord, pharyngeal slits, an
endostyle, and a post-anal tail
Chordates

3. Evolution of Chordates
● First seen 896 million years ago
● Classified as deuterostomes because the tail develops before the mouth
● Evolved from invertebrate chordates to vertebrates to complex vertebrates
like fish to amphibians to mammals

4. Chordate Development
● Through cephalization, nerve tissue develops one side of the body, eventually becoming a head
● The vertebral column of ancient chordates was known as the notochord and helped stiffen the
body and protect the spinal cord with cartilage

5. Evolution of Fish and Amphibians
● Scientists believe that amphibians were the next evolutionary step down
from fish
● The pectoral and pelvic fins evolved into 4 legs
● The gills were sealed and lungs evolved

6. Classes of Fish
● There are 3 classes of fish: the Agnathans, the Chondrichthyans, and the Osteichthyans

7. Agnathans
● The Agnathans are boneless, eel-like creatures that have gone relatively unevolved for 300
million years
● The most common species are the hagfish and the lamprey
● Agnathan means lacking jaw
● They also lack paired pectoral fins which is present in all other fish
● Hagfish have boneless mouths for sucking while lampreys have teeth to bite their prey
● Hagfish are also known for producing copious amounts of slime and eating their prey from the
inside out

8. Chondrichthyans
● The Chondrichthyans are boneless fish whose skeleton is made entirely of
cartilage
● They possess teeth, pectoral fins, and dorsal fins like most fish
● The most famous Chondrichthyan is the shark which has been around for
more than 280 million years
● Other Chondrichthyans include rays and skates

9. Osteichthyans
● The third class of fish is the Osteichthyans which covers 90% of all fish
● They are the bony fish (bone skeleton)
● They also possess an air-filled sac for buoyancy and an operculum to
cover their gills
● There are over 12,000 salt-water species and 6,000 fresh-water

10. Class Amphibia
● Amphibians are tetrapod creatures that begin their lives in water and move
to the land for their adulthood
● There are over 3,900 species, ⅓ of which are considered endangered
● Amphibians are cold-blooded, fresh-water animals
● They are believed to be the evolutionary bridge between fish and reptiles,
mammals, and other terrestrial animals
● The Class Amphibia has 3 orders: Caudata, Anura, Apoda
● Caudata- Salamanders
● Anura- Frogs and toads
● Apoda- Caecilians

11. Phylum urochordata
● Subphylum of Chordates
● Marine
● Hermaphroditic
● Filter feeders
● Body enclosed in secreted protein case
● 2000 species

12. Mindblowing Fish and Amphibian Facts
● Electric eels and electric rays have enough electricity to kill a horse.
● Salamanders dont make sound
● Goldfish can see infrared light
● There’s a shark in Greenland that eats polar bears

13. Trivia!
● What can children with the rare genetic disease phenylketonuria not eat?
o foods high in salt
o foods high in carbohydrates
o foods high in protein
o foods high in fat
● Why? Phenylketonuria is extremely rare and is caused by the pairing of two faulty
recessive alleles (one from each parent), that control the enzyme responsible for breaking
down the amino acid phenylalanine, which is in protein. This why people affected cannot
eat foods high in protein such as meat, milk,cheese, eggs, fish.

14. WOW…
much
fascinate.
such
wow

15. Some Vocabulary!
Notochord - a cartilaginous skeletal rod supporting
the body in all embryonic and some adult
chordate animals
Dorsal Hollow Nerve Cord - is one of the embryonic
features unique to chordates, along with a
notochord, a post-anal tail, an endostyle, and
pharyngeal slits.
http://www.ucumberlands.edu/academics/biology/faculty/kuss/c
ourses/vertbraeribssternum/aboutvertebrae.htm
http://www.bio.miami.edu/tom/protected/CXX/34-02.gif

16. Some Vocabulary!
● Pharyngeal Slits - are filter-feeding organs found in
non-vertebrate chordates and hemichordates living
in aquatic environments.
● Postanal Tail - extension of the notochord and
nerve cord past the anus.http://sunny.moorparkcollege.edu/~econnolly/Fi
shescartilagenousF11_files/image006.png
http://bio.sunyorange.edu/updated2/comparative_anatomy/anat_3/vertebrae_sacrum/3c.jpg

17. Some Vocabulary!
● Segmented Muscles/somites - organizing
segmental muscle patterns of mammalian (human)
body plan
● Urochordates/Tunicates - this subphylum of
chordata is composed of marine animals that look
like small sacs, the adults are sessile, filter sea
water through slits, no notochord, nerve cord, or
tail, larva are free swimming with all features.
http://www.ucmp.berkeley.edu/chordata/urochordata.gif
http://upload.wikimedia.org/wikipedia/commons/f/f9/Gray20nl_somite_highlight.png

18. Some Vocabulary!
Lancelets - a small elongated marine invertebrate that
resembles a fish but lacks jaws and obvious sense
organs. Lancelets possess a notochord and are
among the most primitive chordates.
● Paedogenisis - evolutionary in which the larval
stage develops reproductive structures.
http://life.bio.sunysb.edu/marinebio/larv_27.jpg
http://mosas.sysu.edu.cn/genome/images/in_images/amphi_organ.jpg

19. Some Vocabulary!
● Neural Crest - Although derived from the ectoderm,
the neural crest has sometimes been called the
fourth germ layer because of its importance.
(quoted in Thorogood 2009) from National Institute
of Health
● Closed Circulatory System - Closed circulatory
systems have the blood closed at all times within
vessels of different size and wall thickness. In this
type of system, blood is pumped by a heart through
vessels, and does not normally fill body cavities.
http://upload.wikimedia.org/wikipedia/commons/thum
b/6/60/Neural_crest.svg/2000px-
Neural_crest.svg.png
http://science.kennesaw.edu/~jdirnber/Bio2108/Lecture/LecPhysio/42-02-
OpenClosedCircSys-AL.gif

20. Some Vocabulary!
● Gnathostomes - these are vertebrates with jaws!
● Tetrapods - vertebrates with two pairs of limbs with
digits, have ears, have lungs and includes
mammals, amphibians and birds and other reptiles.
http://upload.wikimedia.org/wikipedia/commons/6/66/Extant_tetrapoda.jpg
http://jl170.k12.sd.us/Bull_shark1.jpg

21. Some Vocabulary
● Amniotes - an animal that possess an “amniotic”
egg (an egg in which the embryo is surrounded by
membranes that form a fluid filled sac and assists
in gas exchange)
● Agnathans - these are jawless fish with no
moveable mouth parts and no paired fins.
http://img1.wikia.nocookie.net/__cb20120801002451/spongebob/i
mages/4/49/Hagfish.jpg
http://animalia-life.com/lamprey.html
http://www.mhhe.com/biosci/genbio/enger/student/olc/art_quizzes/genbiomedia/0
552.jpg

22. Trivia!
● How long is the memory span of a fish?
o 3 seconds?
o 5 months?
o up to 2 years?
o 1 minute?

23. I just
pooped,
but that
fact was
cool.

24. Some Vocabulary!
Osctracoderm
Placoderm
http://facweb.furman.edu/~wworthen/bio440/evolweb/ordovician/ostracoderm.htm
Paraphyletic group of
http://autocww.colorado.edu/~flc/E64ContentFiles/PaleontologyAndFossils/Placoderm.htm
primitive, jawless fish Armor-
plated, jawed fish

25. Some Vocabulary!
Chondrichthyes Lateral Line
Oldest existing Receptor cells
of the nervous
jawed vertebrates system which
allow fish to sense
sound
and vibration
http://vertebrates.voices.wooster.edu/chondrichthyes/ www.amazonian-fish.co.uk

26. Some Vocabulary!
● Oviparous = egg laying
● Viviparous = live bearing
● Oviviparous = eggs hatch
in body, live bearing

27. Some Vocabulary!
Cloaca
Osteichthyes
Cavity in digestive tract for Bony fish (largest class of
vertebrates)
release of excretory and genital
products

28. Some Vocabulary!
● Operculum
o the gill cover of bony
fish
● Swim bladder
o a gas-filled sac
present in the body
of many bony fish,
used to maintain and
control buoyancy
http://www.geol.umd.edu/~tholtz/G331/lectures/331vertsI.html
http://aqua-fanatic.blogspot.com/2011/06/swim-bladder-
disorder.html

29. Some Vocabulary!
● Ray-finned fish
o fish that have thin fins
strengthened by slender rays
(including all bony fishes apart
from the coelacanth and
lungfishes.)
● Lobed-finned fish
o fish of the class Sarcopterygii,
having fins that are rounded and
fleshy, suggesting limbs.
http://releeps.tripod.com/cgi-bin/
http://www2.estrellamountain.edu/faculty/farabee/BIOBK/BioBookDiversi
ty_9.html

30. Some Vocabulary!
● Tetrapod
o “four legs” in Greek
o Includes Amphibians, Reptiles, Birds, and Mammals
o Have four limbs or ancestors with four limbs
● Amphibian
o “double life” in Greek
o Includes frogs, toads, newts, and salamanders
o Cold-blooded
o Can live on land and in water

31. Some Vocabulary!
● Caecilian
o tropical amphibians
o no eyes
o retractable tentacles
o burrow

32. Fun Trivia!
● Anemophobia is the fear of what?
● Wind
● Fire
● The Dark
● Spiders
Answer is the wind!

33. Lauren Moon Reid Merriken
Bobby Hix