Phylum chordata-An overview

Phylum Chordata and its Characteristics with simplified Classifications

By: Sarwar AD
Research Scholar
GC University Lahore Pakistan

1. SDSC, GC University Lahore
Course Title: Animal Diversity (Chordates)
Course Code: Z-3111
Presented By: Sarwar AD

2. Phylum Chordata
Charactertisticsof Chordates
All chordates possess a notochord.
•Long felxablerod between gut
& nerve cord
•Runs most of length of animal
Possess a dorsal, hollow, nerve cord
Possess pharangealslits
Muscular post-anal tail

3. Phylum Chordata

4. Phylum Chordata

6. Subphylum Urochordata
Commonly called turnicates
Sessile marine animals as
adults -Motile as larva
Larva possess a clear
notochord which is less
evident in adults
Filter feed through use of
siphon
Subphylum Urochordata

7. Subphylum
Urochordata

8. Subphylum Cephalochordata
Commonly known as lancets
Have all features of the ideal
chordate
Bury selves in sand, and
filter-feed through mouth

9. Subphylum Vertebrata
Seven extantclasses
First 3 commonly called fishes
Remaining 4 called tetrapods(4 feet)
All possess some form of segmented vertebra
Subphylum Vertebrata

10. •Commonly known as Jawless Fish
•Include hagfish& Lampreys
•Lack paired appendages
•Lack bony skeleton
•Lack jaws
•Usually have circular sucking mouthparts
•Lampreys parasitize other fish
Class Agnatha

11. Lampreys

12. Hagfish

13. Include sharks & skates, & rays
Very successful class
Called cartilagenous fishes because skeleton is
cartilage not bone
Approx. 750 species
Have paired appendages
Many have acute senses
Sharks have a lateral-line system
Allows shark to detect water pressure changes
Class Chondrichthyes

14. Sharks

15. Noteworthy Shark Species
Great White Shark
Tiger Shark
Whale Shark
Bull Shark

16. Rays & Skates
Manta Ray Southern Stingray
Skates

17. Class Osteichthes
Called Bony fish
Most diverse of all fish
Have skeleton made of bone
Have Cycloid Scales
Have paired fins
Allowed evolution of 4 limbed
amphibians (tetrapods)
Possess scales for protection
Have bony flap called operculum
Allows water to be drawn over
gills by fins
Have Swim bladder
Gas content can be manipulated
allowing for changes in bouyancy

18. Bluefish

19. Class Amphibia
First vertebrates to inhabit land
Most are 4 limbed (tetrapods)
Include frogs, salamanders& caecilians
Have 3 chambered heart
Have more complicated gas exchange organs
(often a combination of lungs, gills and skin)

20. Order Urodela
(Salamanders & Newts)
Urodela("tailed ones" -Salamanders)
More dependent on water
Many species possess gills as adults

21. Class Apoda
("tail-less ones" -Frogs & toads)
Have more developed lungs than salamanders
Lack a diaphragm& must “swallow” air
Most diverse and common of amphibians.
Toads are the first amphibians to evolve keratinized
skin.
This waterproofs the skin preventing water loss
Toads must still return to water to lay eggs.

22. Common North American Frogs
North American Toad Green Frog Bullfrog
Leopard Frog Poison Arrow Frog

23. Caecilia("legless ones")

24. Reproduction
Lack internal fertilization&
amniotic eggs
Reproduction must occur in H2O
Most species undergo
metamorphosis
Larval stage (tadpole) is
usually an aquatic herbavore
Lacks legs, respiration is
through gills
Develops into tetrapodadult
(usually carnivorous)

25. Class Reptilia
Includes lizards, snakes, turtles, and crocodilians
Over 7000 species
Possess several advanced features over amphibians
Most adaptations towards independence from H
2O
Possess scales containing keratin
Keratin is a waterproofing protein which prevents water loss in an
organism
Possess an amniotic egg.
Prevents water loss of embryo. Allows for eggs to be laid on dry land
Combined with internal fertilization, allows reptiles to reproduce
independently of water
Reptiles are "cold blooded" or ectotherms
Cannot internally regulate body temperatures
Reptiles can regulate body temperatures behaviorally (eg. Basking or
swimming)
Nutritional requirements are lower than warm blooded animals

26. The Amniotic Egg

27. Modern Reptiles
Order Chelonia(Turtles & Tortoises)
Inhabit aquatic and terrestrial
environment.
Are herbavores, carnivores, and
omnivores
Characterized by possessing a hard
dorsal shell
Made from bone, extensions of
backbone and rib cage

28. Common Turtles

29. Order Squamata
Order Squamata(Lizards & Snakes)
Most numerous & diverse of the reptiles
Most relatively small Although monitors and their
relatives can grow to 6' in length
Herbivores, carnivores & omnivores
Most able to exhibit some form of hibernation

30. Noteworthy Lizards
Eastern Fence Lizard
Leopard Gecko
Komodo Dragon
Anole

31. North American Snakes

32. Order Crocodilia
(Crocodiles, Alligators, & Caimans)
Largest extant reptiles can grow to over 15’ and
weigh over a ton
Primarily aquatic they are true reptiles
Inhabit warm, tropical climates
Order most closely related to the dinosaurs

33. Crocodilians
Crocodile Alligator
Caiman

34. Class Aves
(The Birds)
Evolved from dinosaurs during
Mezozoicera.
Aminotic eggs and scales on legs
reminants of reptilian origins
Almost all adaptations of these
animals are made for flight.
Presence of feathers
Made of keratin
Can be used for insulation and
flight
Forelimbs developed into wings
Honeycombed, light bone structure

35. Feathers

36. Beak Types
Absence of some organs
Females usually have 1 ovary
Absence of teeth lighten head
Replaced by gizzardin
abdomen & beak
Beak made of keratin
Proven very adaptable
structure, having a variety of
shapes for differing diets

37. Reproduction
Reproduction is through hardened amniotic eggs
Since birds are endothermic, these must be kept
warm by parents
This behavior called brooding

38. Birds Feet

39. Modern Birds
•Over 8600 species & 20 orders of
birds
•Classified into 2 general groups
•Flightless species including
ostrich, emus, & kiwis are known
as ratites
•Lack sternal keelon breastbone
•Lack strong breast muscles needed
for flight
Ostrich: A ratite

40. Modern birds contd.
Other species capable of
supporting flight called carinates
60% are "perching birds" called
passeriforms
Possess a sternal keelon
breastbone
Support strong breast muscles
required for flight
The sparrow: A passeriformcarinate

41. Class mammalia
Approx. 4500 species of mammals
Evolved from mammal-like reptiles called
therapsidsin the triassicperiod
Diversified greatly following the
extinction of dinosaurs
Mammalian Characteristics
Have Hair
Made of keratin
Aids in maintaining body
temperature
Endothermic
Maintain body temperature internally

42. Have efficient respiratory system including a
diaphragm
Efficient circulatory system with a 4-chambered
heart
Most possess placentas and give birth to live young
Have mammary glands to produce milk for
offspring
All show parental care of offspring
Have largest brains of all vertebrates
Have differentiated teeth
Unlike earlier vertebrates, several different teeth can
exist in mammal jaws
Eg. The molars & incisors in the human jaw
Class mammalia

43. General Types of Mammals
Monotremes
Early branch from reptilian
line
Include platypuses&
echidnas(spiny anteaters)
Only group to lay eggs
(reptilian in structure)
Have mammary glands to
feed young
Duck Billed Platypus
Echidna

44. Marsupials
Include opossums, kangaroos & koalas
Mostly found in Australia & New Zealand
Were isolated in these landmasses when the
continents separated and did not evolve li the
same way placental mammals did
Do not develop placentas
Give birth to young very early
Fetuses complete development in pouch called
marsupium
Mammary glands found in pouch nourish young
until development is complete

45. Examples of marsupials
Opossum Koala
Kangaroo

46. Placental Mammals
Complete embryonic development in uterus
Joined to parent by organ called placenta
Only "disposable" mammal organ
Discarded following birth
Exchanges gasses, nutrients & waste between
mother and fetus

47. Common Mammals 1

48. Common Mammals 2