The document discusses the phylum Chordata, which includes animals that possess a notochord, post-anal tail, and pharyngeal pouches. It is divided into 3 subphylums: Urochordata (tunicates), Cephalochordata (lancelets), and Vertebrata. Vertebrates are further divided into 7 classes: Agnatha (jawless fish), Chondrichthyes (cartilage fish), Osteichthyes (bony fish), Amphibia, Reptilia, Aves (birds), and Mammalia. Each class is described in 1-2 sentences highlighting their key characteristics.

2. Animal Diversity: Invertebrates
by
Maryam Riasat
PHYLUM CHORDATA

4. Phylum Chordata
 Chordata derived from Greek word chorde means “string” and
cord ata means “bearing”
 Animals possessing
o A notochord
o A post anal tail
o Pharyngeal pouches (gill slits)
either thought out their life or during early embryonic life
 The notochord is stiff and flexible rod like structure

5. General Characteristics
 Aquatic, terrestrial or aerial
 All free living, no parasitic
 Bilaterally symmetrical
 Exoskeleton
 Cartilaginous or bony endoskeleton
 Complete digestive system
 Closed blood vascular system
 Excretory system
 Dorsal and tubular nerve cord

6. Taxonomic summary

7. Subphylum Urochordata
 Marine animals, includes
Tunicates
 Some species are solitary,
others are colonial
 Sessile as adults, but motile
during the larval stages
 Settle head first on hard
substrates and undergo a
dramatic metamorphosis
(e.g., tail, notochord,
muscle segments and nerve
cord disappear)

8. Subphylum Cephalochordata
 Exclusively marine animals
includes Lancelets
 Have closed circulatory
system and diffuse gas
through their skin
 Although they are capable
of swimming, they usually
are buried in the sand with
only their anterior end being
exposed

9. Subphylum Vertebrata
Vertebrates include
1. Agnatha: Jawless Fish
2. Chondrichthyes: Cartilage Fish
3. Osteichthyes: Bony Fish
4. Amphibia: Amphibians (Double life organisms)
5. Reptilia: Reptiles
6. Aves: Birds
7. Mammalia: Mammals

10. Agnatha
 The agnathans are the
jawless fishes
 Members of this group
include the lampreys and
hagfish
 Lack bony skeleton
 Usually have fins and scale
covered skin
 There are very few agnathan
species alive today
 The lampreys are
ectoparasites while the
hagfish is a scavenger

11. Chondrichthyes
• Chondrichthyes include
sharks, skates and rays
• Cartilaginous skeleton
• Have scales and biting
mouth parts
• Paired fins, tooth like scales
cover body
• Ectothermic
• Complete digestive system
with large stomach
• Move constantly in order to
breath

12. Osteichthyes
 Osteichthyes includes salmon,
trout and carps
 Jawed fishes having a bony
endoskeleton
 Respiration by gills supported
by bony gill arches and
covered by a operculum
 Mouth with many teeth (some
toothless)
 Body covered by overlapping
scales

13. Amphibia
 Spends double life, first stages of
life in water and later on land
 Have no nails or claws
 Minimal number of teeth
 Most have a tongue that is
projectile and sticky
 They are ectotherms
 The skin is smooth and rough
without any scales, but with glands
that make it moist
 Contains mucous glands, poison
glands and pigment cells

14. Reptilia
 Reptiles includes turtles,
crocodiles, lizards and snakes
 Burrowing terrestrial animals
 Their bodies are completely
covered with scales
 Skin is dry, rough and without
glands
 Limbs may or may not be present.
If they have limbs, they are two
pairs of pentadactyl limbs, each
bearing claws
 Snakes do not have limbs.
 Produce shelled eggs or bear live
young.
 All species fertilize eggs
internally

15. Aves
 Aves includes pigeons, owls and
flamingos
 Birds are bipedal and clawed
vertebrates
 Body is covered by feathers
 Body is divisible into head, neck,
trunk and tail
 Have no teeth.
 Have sharp eyesight.
 Forelimbs are modified into wings
 Hind limbs are strong and are
useful to walk
 They have well developed flight
muscles

16. Mammalia
 Mammals includes human, lion,
dog gorilla and monkey
 They are the most dominant form
of animals found in almost all
types of habitats
 They have mammary glands that
help them produce milk
 Body is covered by fur and hairs
 They are heterodont, i.e. possess
different types of teeth
 Good sense of hearing as
mammals are aided with 3 middle
ear bones
 Mammals have a four chambered
heart
 The brain is well developed