Ch 03: Animal World | Exam Fusion Prep

Eukaryotic

Cell Type

Multicellular

Organisation

Heterotrophic

Nutrition

Mostly Motile

Movement

Absent

Cell Wall

🐾 Animal Kingdom — Key Features

Eukaryotic organisms
Multicellular, Heterotrophic
Mostly Motile
Cell wall Absent

⚡ Quick Recall

Animals vs Plants: Animals mein Cell wall absent, Plastids absent, Heterotrophic hain. Plants mein cell wall + plastids present, Autotrophic hain.

🔀 Animal Classification — Big Picture

A. Non-Chordata

Notochord absent
I. Porifera
II. Cnidaria
III. Ctenophora
IV. Platyhelminthes
V. Aschelminthes
VI. Annelida
VII. Arthropoda
VIII. Mollusca
IX. Echinodermata
X. Hemichordata

B. Chordata

Notochord present (at some point in life)
Dorsal hollow nerve cord
Pharyngeal gill slits
Urochordata (e.g. Herdmania)
Cephalochordata (e.g. Amphioxus)
Vertebrata / Craniata

Urochordata + Cephalochordata = Protochordate

I. Porifera (Sponges)

Asymmetrical, acoelomate, porous aquatic — "Sponge"
Canal system + Cellular aggregate level organisation
High capability of Regeneration
Collar cells (Choanocytes) present

Freshwater:Spongilla Bath sponge:Euspongia Other:Sycon (Scypha)

⚠ Exam Trap

Porifera mein Choanocytes (Collar cells) unique hain — sirf inhi mein milti hain. Regeneration bhi high hai.

II. Cnidaria

Stinging cells (Cnidocytes / Cnidoblasts) present
Radial symmetry, gastrovascular cavity present
Aquatic, Diploblastic, acoelomate, tissue-level organisation
Polymorphic: Polyp (sessile) and Medusa (free-floating)

Physalia:Portuguese man-of-war Adamsia:Sea anemone Pennatula:Sea pen Other:Hydra

III. Ctenophora

Radial symmetry, Sea walnuts, marine
Bioluminescence ability
Diploblastic, acoelomate
Comb jellies — eight rows of ciliated comb plates

Example:Ctenoplana

⚡ Quick Recall

Ctenophora = Bioluminescence (light emit karna) + 8 comb rows. Ye dono unique features MCQ mein aate hain.

IV. Platyhelminthes (Flatworms)

Flatworms, usually endoparasitic
Organ level organisation, Triploblastic, acoelomate, bilateral symmetry
Flame cells present for excretion
Incomplete digestive system
Sucker and hooks present
Regeneration in Planaria

Tapeworm:Taenia solium Liver fluke:Fasciola

⚠ Exam Trap

Platyhelminthes mein excretion = Flame cells. Annelida mein = Nephridia. Arthropoda mein = Malpighian tubules. Ye teen confuse karne wale facts hain!

V. Aschelminthes (Nematodes / Roundworms)

Nematodes, usually endoparasitic
Dioecious (separate sexes), Pseudocoelomate
Cylindrical, bilateral symmetry
Complete alimentary canal
Excretion through Renette cells (gland cells)

Roundworm:Ascaris Filarial worm:Wuchereria Hookworm:Ancylostoma

VI. Annelida (Segmented Worms)

Cylindrical, worm-like segmented body
Organ system level organisation
Excretion through Nephridia
Haemoglobin (respiratory pigment) dissolved in plasma
Closed circulatory system
Respiration through skin
Coelomate

Nereis:Nereis Earthworm:Pheretima Blood-sucking leech:Hirudinaria (33 segments)

VII. Arthropoda (Jointed Appendages)

Largest phylum — ⅔ of all species are insects
Chitinous exoskeleton, Open circulatory system
Body: Head + Thorax + Abdomen
Respiratory organs: Gills, Book gills, Book lungs or Trachea
Statocysts for maintaining body balance
Excretion through Malpighian tubules

Economic/Social Insects

Bees — Apis indica
Silkworm — Bombyx mori
Lac insect — Laccifera lacca

Vector Insects

Anopheles (Mosquito)
Culex (Mosquito)
Aedes (Mosquito)

Special

Living fossil: Limulus (King Crab)
Shrimp, Scorpion, Grasshopper (Locusta)

⚠ Exam Trap

Arthropoda = Largest phylum of animals. Mollusca = Second largest. Ye order yaad rakho! Living fossil = Limulus (King Crab).

VIII. Mollusca (Soft-bodied)

Second largest phylum, soft-bodied animals
Body: Head + Muscular foot + Visceral mass
Shell composed of Calcium carbonate (CaCO₃)
Respiration through Ctenidia
Food grinding by Radula
Excretion through Bojanus organs

Apple snail:Pila Pearl oyster:Pinctada Cuttle fish:Sepia Other:Octopus, Aplysia, Dentalium

IX. Echinodermata (Spiny-skinned)

Endoskeleton of calcareous ossicles with spines
Tube feet — part of Water Vascular System
Radial symmetry (larvae: bilaterally symmetrical)
High regeneration capability
Brain absent
Aristotle's lantern → food grinding (in Sea urchin)

Starfish:Asterias Sea urchin:Echinus Sea cucumber:Cucumaria Brittle star:Ophiura

X. Hemichordata (Half Chordates)

Connecting link between Non-chordates and Chordates
Body: Proboscis + Collar + Trunk
Usually worm-like marine animals
Open circulatory system
Excretion through Proboscis gland

Examples:Balanoglossus, Saccoglossus

⚡ Quick Recall

Hemichordata = Connecting link (non-chordate aur chordate ke beech). Balanoglossus sabse common example hai exams mein.

🧬 Chordata — Main Characteristics

(i) Dorsal Notochord
(ii) Dorsal hollow nerve cord
(iii) Pharyngeal gill slits
Note: These three present at some point during life cycle
Closed Circulatory System

Urochordata:Herdmania Cephalochordata:Amphioxus Together called:Protochordate

Vertebrata / Craniata

Brain, Vertebral column and Cranium present
In adults: notochord replaced by cartilaginous or bony vertebral column
Nerve cord → Brain + Spinal cord

🔀 Vertebrata — Classification Tree

1. Agnatha (Jawless)

→ Cyclostomata
Jawless, cylindrical, aquatic
Sucker-like circular mouth
6–15 pairs of gill slits
Two-chambered heart, ectothermic
Skull + vertebral column = cartilaginous
Examples: Petromyzon (Lamprey), Myxine (Hag fish)

2. Gnathostomata (Bear Jaw)

Pisces / Fishes (Bear fins)
- Chondrichthyes (cartilage)
- Osteichthyes (bone)
Tetrapoda (Bear limbs)
- Amphibia
- Reptilia
- Aves
- Mammalia

🦈 Chondrichthyes (Cartilaginous Fish)

Skeleton made of Cartilage, usually marine
5–7 pairs of gill slits, without operculum
Two-chambered heart
Air bladder absent → continuously swim to avoid sinking
Cold-blooded, oviparous or ovoviviparous (Shark)
Electric organ → Torpedo
Poison sting → Trygon

Dog fish:Scoliodon Sawfish:Pristis White shark:Carcharodon Other:Chimera

⚠ Exam Trap

Chondrichthyes mein operculum absent aur air bladder absent. Osteichthyes mein dono present hain!

🐟 Osteichthyes (Bony Fish)

Skeleton made of Bone
4 pairs of gill slits covered by Operculum
Two-chambered heart
Air bladder present
Cold-blooded, oviparous, unisexual

Marine

Flying fish — Exocoetus
Sea horse — Hippocampus

Fresh Water

Rohu — Labeo
Catla
Walking catfish — Clarias

Aquarium

Fighting fish — Betta splendens

ℹ️ Tetrapoda — Common Features

Four (two pairs) limbs present
Respiration through Lungs
Endoskeleton is Bony

🐸 1. Amphibia

3-chambered

Heart

Cold-blooded

Ectothermic

Oviparous

Reproduction

Found on both water and land
Exoskeleton absent
Mucous glands on outer surface → body flexible
Larvae: Tadpole (frog larva)

Frog:Rana tigrina Toad:Bufo Tree frog:Hyla Blindworm:Ichthyophis Other:Proteus

🦎 2. Reptilia

3-chambered

Heart (mostly)

Cold-blooded

Ectothermic

CaCO₃ eggs

Egg covering

Usually terrestrial, dry skin with Keratinous scales
Creeping animals
Three-chambered heart; eggs covered with CaCO₃
Exception: Crocodile → Four-chambered heart

Cobra:Naja naja Blind snake:Typhlops Other:Lizard, Chameleon, Tortoise, Dinosaur (Extinct)

⚠ Exam Trap

Reptiles mein generally 3-chambered heart — lekin Crocodile mein 4-chambered heart! Ye exception MCQ mein direct poochha jaata hai.

🐦 3. Aves / Birds

4-chambered

Heart

Warm-blooded

Endothermic

Hollow + Pneumatic

Bones

Feathers present on dry skin
Eggs covered with CaCO₃
Forelimbs modified into Wings
Jaws modified into Toothless beak
Hind limbs covered with scales
Bones are hollow and pneumatic (for flight — light weight)
Often adapted for jumping, running, swimming or grasping

Parrot:Psittacula Peacock:Pavo cristatus Pigeon:Columba

⚠ Exam Trap

Flightless Birds: Emu, Ostrich, Penguin, Kiwi, Cassowary — inke wings hain lekin ye ud nahi sakte. Ostrich = world's largest bird.

⚡ Quick Recall — Flightless Birds

Emu · Ostrich · Penguin · Kiwi · Cassowary → EOPKC

🐘 4. Mammalia / Mammals

4-chambered

Heart

Warm-blooded

Endothermic

Mammary glands

Unique feature

Viviparous

Mostly

Hair or Fur present on skin
Mammary glands present (milk production)
Diaphragm present
Exoskeleton: Horns, Hoofs and Nails
Four-chambered heart, Warm-blooded
Viviparous — give birth to young ones
Exception: Platypus and Echidna → Oviparous (egg-laying mammals)

Human:Homo sapiens Bat:Pteropus Kangaroo:Macropus Camel:Camelus

⚠ Exam Trap

Mammals viviparous hote hain — lekin Platypus & Echidna oviparous hain (eggs dete hain). Ye dono Monotremes hain. Ye exception MCQ mein baar baar aata hai!

📊 Vertebrate Classes — Master Comparison

Feature	Chondrichthyes	Osteichthyes	Amphibia	Reptilia	Aves	Mammalia
Skeleton	Cartilage	Bone	Bone	Bone	Bone (hollow)	Bone
Heart	2-chambered	2-chambered	3-chambered	3-chambered (Croc: 4)	4-chambered	4-chambered
Body Temp	Cold-blooded	Cold-blooded	Cold-blooded	Cold-blooded	Warm-blooded	Warm-blooded
Operculum	Absent	Present	—	—	—	—
Air bladder	Absent	Present	—	—	—	—
Reproduction	Ovi/Ovovivi	Oviparous	Oviparous	Oviparous	Oviparous	Viviparous (Platypus: Ovi)
Special	No operculum, always swimming	Flying fish, Sea horse	Tadpole larva, mucous glands	Keratinous scales	Hollow bones, toothless beak	Mammary glands, diaphragm

📊 Non-Chordata Phyla — Quick Reference

#	Phylum	Key Feature	Excretion	Example
I	Porifera	Collar cells (Choanocytes), Regeneration	—	Spongilla, Euspongia
II	Cnidaria	Stinging cells (Cnidocytes), Polyp & Medusa	—	Hydra, Physalia
III	Ctenophora	Bioluminescence, 8 comb rows	—	Ctenoplana
IV	Platyhelminthes	Flatworms, Triploblastic, Acoelomate	Flame cells	Taenia (Tapeworm)
V	Aschelminthes	Nematodes, Pseudocoelomate	Renette cells	Ascaris, Wuchereria
VI	Annelida	Segmented, Closed circulatory, Coelomate	Nephridia	Earthworm (Pheretima)
VII	Arthropoda	Largest phylum, Chitinous exoskeleton, Open circulation	Malpighian tubules	Limulus, Silkworm
VIII	Mollusca	2nd largest, Radula, Ctenidia	Bojanus organs	Pila, Octopus
IX	Echinodermata	Water vascular system, Brain absent	—	Starfish (Asterias)
X	Hemichordata	Connecting link, Proboscis+Collar+Trunk	Proboscis gland	Balanoglossus

⚡ Quick Recall — Excretion Organs

Flame cells → Platyhelminthes | Nephridia → Annelida | Malpighian tubules → Arthropoda | Bojanus organs → Mollusca | Renette cells → Aschelminthes

🐾 Chapter 03 — Animal World