Category: Biology Second Paper

Each region of the body of animals of Arthropoda class is called tagmata. The process by which the animal body is divided into tagmata is called tagmatization. The evolutionary process by which tagmatization is accomplished is called tagmosis. The bodies of animals of the class Insecta of the order Arthropoda are divided into three tagmas. Namely – head, chest and abdomen. For example, grasshopper (Poekilocerux pictus).

The chest gill is a sexual organ. In Arthropoda animals, the skin of the digital floor is folded and forms a breathing organ like a gill like a page of a book is called a chest gill. For example – Macrobrachium resenbergii.

The chest and lungs are organs of the body. The outer skin of the digital floor of Arthropoda animals is folded and arranged like the pages of a book to form the respiratory organ called the book lung. Spider (Lycosa lenta).

A body cavity filled with hemolymph is called a hemocele. It is divided into three chambers or sinuses by the dorsal membrane and digital membrane. Pericardial sinus above the dorsal membrane, perivisceral sinus below the dorsal membrane and perineural sinus below the ventral membrane.

1. The body of the butterfly is thin and covered with soft hairs.
2. The pupa of the batyfly resides within the chrysalis.
3. Adults have slender antennae and head discs.
4. When sitting, the fins are erect.

Flies – Musca domestica
Lobster- Macrobrachium resenbergii
Shrimp – Penaeus monodon
Cockroach- Periplaneta americana
Horse-hoofed crab – Tachypleus tridentatus
Limulus- Limulus polyphenus
Mosquito – Culex pipiens
Dengue mosquito- Aedes aegypti
Bee – Apis mellifera
Spider- Lycosa lenta
Grasshopper – Oxya chinensis
Butterfly – Papilio xuthus
Centipede- Scolopendra laeta
Thousand feet – Julus terrestris
Crab- Scylla olivacea
Beetle- Scolopendra gigantea
Barnacle – Balanus balanus
Hunting Mantis – Mantis religiosa
Bookworm- Lepisma saccharina
Buthus- Buthus tamulus

The order Arthropoda is divided into several suborders.
1. Trilobitomorpha: These are invertebrate arthropods. Their exoskeleton is strong. They are the most diverse.
2. Crustacea: Their bodies are soft and three-layered. Real Siloam exists. Has two pairs of antennae. Has two compound eyes. The body is divided into segments. For example – Bagda shrimp (Penaeus monodon).
3. Calicerata: These are eight-jointed joints. The body is divided into head and torso. They don’t have wings. There are poison glands in the body. For example – Spider (Lycosa lenta)
4. Hexapoda: Their body is chitinous and divided into head, thorax and abdomen. The thorax has a pair of jointed legs and a pair of wings. Has a branched tracheal system. Respiration is done by air ducts. Free circulatory system exists. Excretion is accomplished by the Malpighian duct

1. They are triploblastic organisms, bilaterally symmetrical and segmented.
2. The body is divided into tagmata. The body is divided into head, thorax and abdomen.
3. They are animals with jointed appendages. The head has a pair of antennae and a pair of antennae.
4. The appendages of the body are changed to form the mouth. It takes food.
5. The exoskeleton is made up of cuticles and regularly sheds or molts.
6. The body cavity is known as hemocele. It is filled with blood.
7. Their main excretory organ is the Malpighian duct. But excretion is also done by green gland, chyloe, coxal gland, antennal gland and maxillary gland.
8. The circulatory system is open type. It consists of the heart, arteries and hemocele.
9. Respiration is accomplished through their trachea, gills, skin, gills, or pectoral fins.
10. Men and women are separate animals. Their internal fertilization occurs. Turns into an explosion.
11. The life cycle consists of larva, pupa and nymph stage.
12. They live as terrestrial, aquatic, sessile, free-living, parasitic or symbiotic.
[Key words to remember features: triploblastic, tagmata, pujakshi, moulting, hemocele, malpighian duct, chest lung]

The term Arthropoda is formed from the Greek words arthros meaning jointed and podos meaning foot. Those animals whose body has jointed appendages, bilaterally symmetrical, free circulatory system, hemoceles and exoskeleton containing chitin are called Arthropoda. Arthropoda is the largest group of animals. 80% of animals in the fauna are arthropods. The number of species is about 12,57,040. They are herbivores, carnivores or omnivours. Von Siebold (1845) named the order Arthropoda.

The word Annelida is derived from the Latin word annelus meaning small ring and eidos meaning shape. Animal bodies that are triploblastic, cylindrical, ring-like segments or metameres are called Annelida. The animals of this phase are known as ringworms or segmented worms. Phlebotomy is the process in which a starved leech is attached to the body to suck the contaminated blood from the body. The number of species in this category is about 17,338. Lamark (1809) identified soft-bodied animals as Annelida.

Characteristics of Annelida
1. Body long, cylindrical, bilaterally symmetrical and with true cylomes.
2. The body is segmented and composed of many segments or metameres similar to rings.
3. Movement organs are chitinous seatae or parapodia.
4. Patchy excretory organs called nephridia are located in almost every segment. It is called segmental organ.
5. The body contains the clitellum and secretes mucus.
6. The alimentary canal is cylindrical and complete and consists of oral and anal openings.
7. Blood is red. Plasma contains hemoglobin, heme-erythrin or chloroquine.
8. The body is composed of chitinless and soft cuticle.
9. The larval stage of the life cycle consists of trochophores.
10. They are unisexual or bisexual. Reproduction occurs sexually and asexually.

[Key words to remember features: metamere, seatae, parapodia, nephridia, trochophore]

Classification of Annelida
The order Annelida is divided into 3 classes.
1. Polychaeta: Their body parts are covered with hairs. locomotion parapodia. Sensory organ is nucell organ. They are mostly marine. For example, Nereis caudata.
2. Oligochaeta: These are leech-like creatures. They live by digging holes. For example, Metaphire posthuma.
3. Hirudinia: They have clitellum. There is a substance called hirudin in the body. For example, Hirudinaria medicinalis.

Some animals of Annelida
Leech- Hirudinaria medicinalis
Nereis- Nereis/Neanthes caudata
Spectacular insect – Amphrite figulus
Arenicola – Arenicola marina
Earthworm- Metaphire posthuma
Terebella lapidaria
Haemopis- Haemopis terrestris
Pontopdella- Pontopdella muricata
Hairy Worm- Hediste diversicolor
Blood worm- Glycera convoluta
Lumbricus- Lumbricus terrestris
Parchment worm- Chaetopterus variopedatus
Red worm – Eisenia foetida
Tubifex – Tubifex tubifex
Sea Lice – Aphrodite aculeata
Ornate Worm- Aphrodite ornata
Fan worm- Serpula vermicularis

Nephridia
Nephridia is a type of excretory organ. nephridia It collects nitrogenous wastes. Passes waste material to the intestines. Plays a role in osmoregulation.