The document discusses the characteristics of chordates and their classification. It notes that chordates are bilaterally symmetrical, triploblastic animals that possess a notochord, dorsal nerve cord, and pharyngeal slits. They are divided into three subphyla: urochordata, cephalochordata, and vertebrata. Vertebrates are further divided into 7 classes: cyclostomes, chondrichthyes, osteichthyes, amphibia, reptilia, aves, and mammalia. Each class has distinct characteristics related to their anatomy, physiology, habitat, and life cycle.
6. a. ROD LIKE STRUCTURE FORMED ON THE DORSOL SIDE
DURING ENBRYONIC DEVELOPMENT
b. ANIMALS WITH NOTOCHORD ARE CALLED CHORDATES
WHICH DO NOT PERFORM THIS STRUCTURE IS CALLED NON
CHORDATES
a. THE BODY IS INTERNALLY AND EXTERNALLY
DIVIDED INTO SEGMENTS .
b. IN EARTHWORM – THE BODY SHOWS
METAMERIC SEGMENTATION - METAMERISM
7.
8. An undifferentiated layer , mesoglea , is present
In between the ectoderm and the endoderm
, that Develop embryo has a 3rd Germinal layer
, mesoderm
14. EXHIBIT TWO BASIC FORMS CALLED POLYP AND
MEDUSA
POLYP - THEY ARE SESSILE AND CYLINDRICAL –
HYDRA
MEDUSA - UMBRELLA SHAPED AND FREE
SWIMMING - AURELIA
POLUP PRODUCE MEDUSA ASEXUALLY
MEDUSA PRODUCE POLYP SEXUALLY
GORGONIA
PHYSALIA
30. Presence of a Notochord
A Dorsal Hollow Nerve Chord is
Present
Chordates Have Paired Pharyngeal Gill
Slits
31. Chordates stand varied due to many
reasons.
bilaterally symmetrical and
triploblastic.
They are the only Phylum which are
coelomates with organ-system level of
organisation.
They possess a post anal tail and a closed
circulatory system.
33. SUBPHYLA UROCHORDATA AND CEPHALOCHORDATA
ARE TOGETHER REFERRED TO AS PROTOCHORDATES.
THEY ARE EXCLUSIVELY MARINE.
• UROCHORDATA
NOTOCHORD IS PRESENT ONLY IN LARVAL TAIL.
EG: ASCIDIA, SALPA,DOLIOLUM
• CEPHALOCHORDATA
NOTOCHORD EXTENDS FROM HEAD TO TAIL REGION AND
PERSISTENT HROUGHOUT THEIR LIFE.
EG:BRANCHIOSTOMA (AMPHIOXUS / LANCELET)
34. Characteristics
Besides other chordates, vertebrates have:
They possess notochord during embryonic period.
It is replaced by a cartilaginous/bony vertebral column in
adults.
A ventral muscular heart with 2,3 or 4 chambers.
Kidneys for excretion and osmoregulation.
Paired appendages which may be fins or limbs.
ALL VERTEBRATES ARE CHORDATES
BUT ALL CHORDATES ARE NOT VERTEBRATES.
35. Vertebrates are divided into 7 classes :
1. CLASS CYCLOSTOMATA
2. CLASS CHONDRICHYTES
3. CLASS OSTEICHTHYES
4. CLASS AMPHIBIA
5. CLASS REPTILIA
6. CLASS AVES
7. CLASS MAMMALIA
36. Cyclostomes are ectoparasites on some fishes.
They have an elongated body bearing 6-15 pairs of
gill slits for respiration.
Their body does not possess any scales or paired
fins.
Their cranium & vertebral column are cartilaginous.
They have closed circulation.
They are marine but migrate for spawning in fresh
water.
Their life span ends within a few days after spawning.
But their larvae return to the ocean.
37. They are marine animals with streamlined body and have
cartilaginous endoskeleton.
Mouth is located ventrally.
Notochord is persistent throughout their life span.
Gill slits are separate without operculum (gill cover).
Skin is tough, containing minute placoid scales.
Teeth are modified placoid scales which are backwardly
directed. Their jaws are very powerful.
Air- bladder is absent, so they have to swim constantly to
avoid sinking.
38.
39. • They are both marine and fresh water with bony endoskeleton.
• Their body is streamlined.
• Mouth is mostly terminal.
• They have four pairs of gills, covered by an operculum on each side.
• Skin is covered with cycloid (ctenoid) scales.
• Air bladder is present which regulates up thrust.
• Heart is two- chambered.
• They too have 2 different genders.
• They possess external fertilization. They are mostly
oviparous and development is direct.
Eg: Exocoetus , Hippocampus, Labeo, Claris
40.
41.
42. o Their possess the creeping or crawling mode of locomotion.
o They are mostly terrestial.
o Their body is covered by dry and cornified skin, epidermal
scales(scutes).Their ears are represented by tympanum.
o Limbs are of two pairs, if present.
o They have a three-chambered heart,excluding crocodiles
which have a four-chambered one.
o Reptiles are cold-blooded animals.
o Snakes & lizards shed their scales as skin cast.
o They have different genders . Fertilisation is internal.
o They are oviparous and development is direct.
Eg: Turtle, Tree lizard, Crocodile, Cobra
43. The presence of feathers, makes them to fly, a
beak and wings(modified forelimbs).
Their hind limbs are modified for
walking, swimming, or clasping branches.
Skin is dry without glands except the oil gland
in the base of the tail.
Endoskeleton is fully bony and long bones are
hollow.
44. The digestive tract has additional
chambers, crop & gizzard.
Heart is four-chambered and they are
warm-blooded animals. Respiration is
done by lungs.
They have different genders.
Fertilisation is internal. They are
oviparous & development is direct.
Eg: Crow, Pigeon, Parrot, Ostrich, Vulture
45. found in a variety of habitats.
Some are adapted to fly or live in
water.
they possess milk producing glands by
which their young ones are nourished.
They have two pairs of limbs, for
walking, running, climbing, etc.
46. Their skin possess hair.
External ears are present.
Heart is four chambered. Respiration is
done by lungs.
They are warm-blooded.
They have different
genders, fertilization is internal.
They are viviparous and development
is direct.
Eg: Dog, Platypus, Tiger, Rat, Dolphin
