Hemichordata, Chordata, Plasmodium, Paramecium, Earthworm and Frog Notes

HEMICHORDATA

► Marine worm like animals called ‘acorn worms’.

► Hemichordata and chordates have following similarities:

Pharngeal gill slits.
Embryonic invagination of dorsal nerve cord.

► They lack notochord and post anal tail.

►Circulatory system → open type. No respiratory pigment in blood.

►Excretion by proboscis gland or glomerulus.

► Tornaria larva (indirect development with free swimming stage).

► Nerve cord in hemichordate is ventral.

Eg: Balanoglossus, Rhabdopleura, Cephalodiscu.

Balanoglossus(Acorn worm/ Tongue Worm):

► Distinct cranium is absent in adult.

► Known as “Connecting link between Protochordates and Echinoderm”

CHORDATAS

A flexible but supporting skeletal rod, called notochord possessing, in the embryo or throughout the life.

1.Urochordata

Notochord in the tail of larva
Retrogressive metamorphosis (disappear in the adult stage)

Examples; Herdmania (sea squirts), salpa, dolium, pyrosoma (bioluminescent)

2.CEPHALOCHORDATA

Notochord extends to the anterior (head)
Filter feeder
Examples; Amphioxus

3.CRANIATA

BODY TEMPERATURE; Cold temperature (P, A, R) Warm blooded (b, M,)
CRANIAL NERVES; 10 PAIRS (P, A,) 12 PAIRS (R, B, M,)
KIDNEY; mesonephric (P, A,) METANEPHRIC (R, B, M,)
EXCRETA; AMMONOTELIC(P), UREOTELIC (A, M), URICOTELIC (R, B)
EGG; Clidoic (B, R) nond (P, A, M)
Heart chamber; 2(p) 3(A, R) 4(B, M and crocodile)
Development Embryo; oviparous (P, A, R, B) viviparous(m)
Type of teeth; homodont (P, A, R) hererodont(m)
Attachment of teeth; Acrodont (P, A, R) Thecodont(M)
Condyle; Condylic (R, B) dicondylic (P, A, M)

PISCES

PLACODERMA (primitive fish e.g. climatius)
CHONDRICHTHYES
OSTEICHTHYES

Chondrichthyes

Study of skates, rays and sharks is called torpedology
Swim bladder absent, endoskeleton cartilaginous
Cilla slits not covered with opercula except chimera
Ampulla of lorenzini present in snout of shark and is a thermoreceptor
Mermaid purse refers to egg capsule of shark and skates
Torpedo is electric ray; electric organ is modified muscles.
Exoskeleton formed of placoid scales
Scroll valve in intestine
Example: scoliodon (dog fish), torpedo (electric ray0, chimera (rat fish or the king of herrings)

Osteichthyes

Cills covered by bony operculum
Swim bladder present and scroll valve is absent
Exoskeleton and formed by cycloid or ctenoid
Lung fish; neoceratodus (Australian lungfish0
- ; protopterus (African lungfish)
- ; lepidosiren (American lungfish)

Coelacanth, latimera chalumnae is living fossils.
Lateral line organ found in osteichthyes
Heart of fish has all venous blood
- Fish liver oil- vitamin D
- Cod liver oil- vitamin B12

BONY FISH; EQUAL TAILAND MOUTH TERMINAL

CAERILEGIOUS FISH; UNEQUAL TAIL AND MOUTH NOT TERMINAL

MALE PREGNANCY IN SEA HORSE (HIPPOCAMPUS)

JELLYFISH-COELENTERATA

SILVERFISH- ARTHOPODA

CRAYFISH- ARTHOPODA

RAZORFISH-MOLLUSCA

CUTTLEFISH-MOLLUSCA

DEVILFISH; MOLLUSCA

SATRFISH; ECHINODERMATA

HAGFISH; CHORDATA

SUPERCLASS (TETRAPODA)

AMPHIBIA

Originated during Devonian period of Paleozoic era

Dominated during carboniferous period (age of amphibian)

Erythrocytes large, oval, biconvex, and nucleated

External fertilization (frog), internal fertilization(salamands)

ORDER;

APODA (limbless, e.g.; ichthyophis)
UROPODA (tail bearing e.g.; Ambystomia, salamanders, tympanum absent, can show neoteny)
ANURA (tail absent in adult)

Horned toad- Phrynosoma (not amphibian)

Hyla; tree frog

Rhacophorus- flying frog

Reptilia

Herpetology is the study of reptiles
Originated during carboniferous period of palaeozoic era.
Mesozoic era is called ‘’ GOLDEN AGE OF REPTILES’’
Seymouria is connecting link between amphibian and reptiles.
Heart is 4- chambered in crocodile, alligators and gaviallis.
Jacobson’s organ (roof of buccal cavity, smelling) well developed
Sphenodon has pineal or parietal or third age.
Lizard shows autotomy.
Saurology id the study of lizard.
Draco- flying dragon
Heloderma- cilia monster (only poisonous lizard)
Sea snake; myotoxin
Viper; haemotoxin
Colora and kraits; neurotoxic
Foramen of panizzae is an aperture in the heart of lizard and crocodile. It is located at the point where right and left aortae cross each other and are in contact.

Aves

Originated from saurapsid lizard
Ornithology (study of birds), oology (study of bird’s egg)
Nidology (study of bird’s nest)
Phenology (study of bird migration)

Archaeopteryx-connecting link between bird and reptiles
Uropygial or preen gland at tail base
Clavicles joined to form v-shaped furcular or wishbone
Sound box or syrinx produce sound
Urinary bladder absent
Pecten is found in all bird except kiwi
Pecten is comb- like structure found in eyes near blind spot
Female are oviparous with single left function ovary and oviduct
Dodo is recently extinct bird from Mauritius.

Mammals

Mammals evolved from reptile from Triassic period of coenozoic era.
Body covered with hair, in whale fat layer blubber is present
Skin has sweat and sebaceous gland
Diaphragm separate thoracic cavity from abdominal cavity
Cervical vertebrae 7 except – (6- sea cow, two teethed sloth)

(8- ant bear)

(9-three toed sloth)

Absence of cloaca (except in monotremes)
Tectorial membrane in ear, corpus callosm in brain, Is present
Mammalian embryo has parasitic mode of nutrition.
RBC, biconcave, oval, non-nucleated except camel and liama

Protheria- ornithorhynchus (duck billed platypus)
Eutherian (spiny ant eater)
Metatheria- macropus(kangaroo), koala\

Locomotion of kangaroo is saltorial

Eutherian-

Protheria has one monotremata, metatheria also has one order marsupial and eutherian has 16-order

Most distinguishing feature of eutherian is presence of placenta

Most primitive placental mammal is shrew.

Some order

Bat-chiroptera

Rat, squirrel- rodentia

Rabbit- lagomorphal

Whale/ dolphin- cetaceae

Elephant-proboscidea

Monkey / apes/ human- primates

PLASMODIUM

Laveran----------------->discovered malarial parasite in RBCs of man

Ronald Ross-----------------> discovered oocyst stage on gut wall of female Anopheles mosquito.

Grassi----------------->described digenetic life cycle of plasmodium

P. falciparum----------------->Maurer’s dots
P. malariae----------------->Ziemann’s dots
P. vivax----------------->Schuffer’s dots
P. ovale----------------->Jame’s dots
{@ FMVO----------------->MaZaSe Jiyo}

Fever occurs after 72 hours in malariae and after 48 hours in other plasmodium.

Quartan malaria occurs in P. malariae and malignant malaria in P. falciparum.

Incubation period of P. falciparum is 12 days, P. malariae is 28 days and other two is 14 days.

Primary host----------------->Female anopheles mosquito
Secondary host----------------->Man
{Medically it is opposite}

Spopozoite----------------->Cryptozoite----------------->Cryptomerozoite----------------->Schizonts----------------->Metacryptozoites----------------->Micro and macro metacryptozoite

Macro enters new liver cell

Micro metacryptozoite----------------->enters RBC----------------->Tropozoite stage----------------->Signet ring stage----------------->Amoeboid----------------->Rosette(Schizont) ----------------->Merozoite----------------->Gametocyte

Rupture RBC and schizonts are called ghost cells destroyed by the spleen.

Store house of malaria parasite in human’s body is spleen also called grave yard of RBC.

20^th august----------------->Mosquito day
25^th april----------------->Malaria day

Quinine extracted from cinchona tree used to cure malaria.

PARAMECIUM

Slipper animalcule

Coined by John Hill

P. caudatum is most common paramecium and P. bursalaria is green colour due to presence of zoochlorella algae.

Cilia longer in posterior region called caudal taft.

Trichocysts are organs of attachment, earlier considered as organs of offence and defence.

Paramecium is a filter-feeder.

Mega-nucleus is large kidney/bean shaped which divide by amitosis and control metabolic activity.Colour pigment is trophochromatin and is one in number.

Micro-nucleus is small round shaped which divide by meiotic and mitotic division and control reproductive activity. Colour pigment is iodochromatin and number is variable. 1 in P. caudatum and 2 in P. Aurelia.

Kappa particle containing Paramecium produce ‘Paramecin’ responsible for killing.

Posterior contractile vacuole works faster than anterior one.

During conjugation, conjoints come in contact ventrally and 8 daughter paramecium are forme, 4 from each conjugant.

Autogamy is self fertilization occurring in Paramecium Aurelia and 2 daughter paramecia are formed.

Cytogamy----------------->No exchange of genetic material. Occur in P. caudatum and 4 daughter paramecia are formed.

Endomixis(Parthenogenesis) ----------------->Occurs in P. Aurelia and 4 daughter paramecia are formed.

Hemixis(Purification)----------------->Macronucleus break and then unite.

Binary fission in Paramecium is transverse but oblique binary fission present in Euglena.

Reserve food material of Euglena is paremylon bdy.

Gambusia affinis feeds on larvae and pupa of mosquito, which is mosquito fish.

Food vacuole of amoeba is analogous to alimentary canal of an animal or gastrointestinal cavity of hydra.

EARTHWORM

Pheretima posthuma

Nocturnal

Burrowin(Fussorial)

Bilaterally segmented, metamerically segmented (100 to 200 segments)

Segmentation

Each body segment called Metamere or Somite

External by annuli(except clitellum)
Internal by septa(except 1^st four and between 9 and 10)

Dorsal part of body dark and ventral part dark.

Pigmentation due to porphyrin.----------------->from chlorophyll of decaying plant----------------->Circular muscle----------------->Protect from harmful light

Clitellum

14, 15, 16 th segment
Form cocoon, mucus, Albumin
Also called cingulum

Phaosome----------------->Photoreceptor----------------->in prostomium(Phaosome is lens)

Peristomium----------------->Mouth bearing 1^st segment

Pygidium----------------->Anus bearing last segment

Prostomium----------------->Muscle fold in 1^st segment

Setae

Setae found in all segment except 1^st, last and clitellar.
80-100/120 setae are present in each segment.
Seta made upof Chitin so doesnot dissolve in KOH.
Also made upof Scleroprotein and protect from water.
Arrangement setae is perichaetine(Ring).
Seta is embedded in setal sac or setigerous sac
Seta controlled by protractor(extension) and retractor(withdrawl)
Protostome and schizocoelus

Dorsal pore secrete coelomic fluid. It is present after 12 or 13 to last segment.

Chloragogen cell

Analogous to liver of vertebrates
Star-shaped, nucleated
Store reserve food (nutritive)
Deamination of protein and formation ofurea (excretory)

Coelomic fluid also helps in locomotion working as hydraulic skeleton.

Receptors

Buccal receptors

Gustatory(taste)
Olfactory(Smell)

Epidermal receptor----------------->Ventral side----------------->thigmoreceptor

Dorsal receptor----------------->Photoreceptor

Absent in 14, 15, 16
Reduces gradually on posterior side

Nephridia

Septal	Pharyngeal	pho
80-100 pair	3 pair	200 to 250 pair
Nephrostome present	Peptonephric	Forest of nephridia
Terminal duct open into septal excretory duct and then to supra-intestinal duct	6^th open into buccal cavity and 4^th and 5^th open into pharynx	Integumentary nephridia finally pour waste into nephridiophore
Present from posterior side of 15^th segment	Present in 4^th, 5^th and 6^th segment	Present from 7^th to 2^nd last segment
Enteronephric	Enteronephric	Exonephric
Typical nephridia, Open type	Close type	Close type

Excretion of Earthworm

Urea(50%)

Ammonia(45%)

Other(5%)---------------->Creatine, Amino-acid

So, Earthwom is urecotelic.

Septal and pharyngeal nephridia conserve water.

Silicates consumed with food are excreted by Chloragogen cell.

Integumentary nephridia are V-shaped.

Nervous system

Central nervous system

	Nerves arising from	Supplied to
Cerebral ganglia	8-10 pair	Prostomium(1) and buccal cavity(7)
Circumpharyngeal ganglia	2-3 pair	Peristomium and buccal cavity
Fused sub-pharyngeal ganglia	3 pair	2^nd , 3^rd and 4^th
Ventral nerve cord	3 pair	Skin, alimentary canal. Visceral organ

Nerve ring present in 3^rd and 4^th segment and surround pharynx.

Segmental ganglion is present in ventral nerve cord after 4^th .

Nerve cord is ventral and solid.

Nerve cord surrounded by epineurium and then by Perineurium.

Giant fibers are responsible for rapid impulse conduction.

Cerebral ganglia---------------->Neurohormone

Regeneration of clitellum
Maturation of clitellum
Formation of cocoon

Tactile hair on ventral side receive thigmo stimuli.

Reproductive system

Fertilization

Cross---------------->due to protandrous
Reciprocal---------------->due to mutual transfer of sperm
External---------------->due to occurance in cocoon

Cocoon formed by glandular clitellum. One embryo develop directly to form new earthworm.

In Pheretima, divericulum store sperm and ammpulla provide nourishment but opposite in case of other earthworms.

Monocysts present in seminal vesicle show anti-peristalsis to bring out sperm into testes sac.

	Segment
Spermathecae	6,7,8,9
Spermathecal pore	5/6,6/7,7/8,8/9(/ represents between)
Testes	10,11
Seminal vesicle	11,12
Spermiducal funnel	10,11
Testes sac (Enclose 1 pair of seminal vesicle) Seminal vesicle contain fructose.	10,11
Male genital papillae(Hold during ccopulation)	18
Ovary	13
Oviduct	13 and 14
Female genital aperture	14
Accessory gland (attach during copulation)	17 and 19
Prostate gland (dirty gland)	16/17 to 20/21

Alimentary canal

Buccal cavity(Protrusible)

Pharynx ---------------->Muscular and glandular---------------->Suctorial---------------->3^rd and 4^th

Chromophil cell---------------->Saliva=Mucus+Proteases
Dorsal chamber---------------->Ciliated and Glandular
Ventral---------------->Conductory chamber
Effective organ for digestion.

Oesophagus---------------->Goblet cell=Mucus---------------->5h and 7^th segment

Gizzard---------------->Grinding machine, Hard part---------------->8^th segment

Stomach---------------->9^th to 14^th segment

Calciferous gland---------------->Neutralize acidity of soil.

CO2 removal in the form of calcide

Circulatory system

Closed type

RBC absent but red colour because haemoglobin dissolve in blood plasma.

Colourless corpuscles---------------->similar to vertebrates

Respiratory pigment---------------->Haemoglobin

Blood glands---------------->3 pairs(4,5,6) ---------------->produce blood cell and haemoglobin

Lymph glands---------------->26 to last (1 pair each) ---------------->produce phagocytic corpuscles

Longitudinal blood vessel

Dorsal blood vessel(only valvular and blood move from backward to foreward) ---------------->1^st to last segment
Ventral blood vessel---------------->1^st to last segment
Lateral oesophageal blood vessel(only paired) ---------------->1^st to 13^th segment
Sub-neural blood vessel---------------->14^th to last segment
Supra-oesophageal blood vessel(smallest) ---------------->9^th to 13^th segment

Transverse blood vessel

Heart

Lateral---------------->4 pair valve---------------->join dorsal to ventral blood vessel---------------->7^th and 9^th segment
Lateral oesophageal---------------->3 pair valve---------------->join dorsal and supra-oesophageal to ventral blood vessel---------------->12^th and 13^th segment

Dorsal blood vessel

1^st to 13^th segment ---------------->distributing
14^th to last segment---------------->collecting

Ventral blood vessel---------------->Distributing, non-oxygenated

ventrointestinalis transport blood to intestine

Dorsointestinals collect from intestine.

Commissural collect from subneural.