B.Sc. Sem II : - Chordata

 

The animal kingdom is basically divided into two subkingdoms:

(a) Nonchordata – including animals without notochord.

(b) Chordata – This comprises animals having a notochord or chorda dorsalis.While the

Chordata have a notochord at some stage during life; it is not known to exist in the Nonchordata.

• The Chordata is the animal phylum with which everyone is most intimately familiar, since it

includes humans and other vertebrates However, not all chordates are vertebrates.

• All chordates have the following features at some stage in their life (in the case of humans and

many other vertebrates, these features may only be present in the embryos).

• Pharyngeal slits – a series of openings that connect the inside of the throat to the outside of the

“neck”. These are often, but not always, used as gills.

• Dorsal tubular nerve cord – A bundle of nerve fibres which runs down the “back”. It connects

the brain with the lateral muscles and other organs.

• Notochord – a cartilaginous rod running underneath and supporting the nerve cord.

• Post-anal tail – an extension of the body post the anal opening.

ORIGIN OF CHORDATES

It is believed that chordates originated from invertebrates. However, it is difficult to determine from

which invertebrate group of the chordate developed. It is almost constant that chordate ancestors were

soft-bodied animals. Hence, they were not preserved as fossils.

Many theories have been put forward to explain the evolution of chordates; few of them are as follows:

(a) COELENTERATE THEORY:

According to this theory chordates developed from coelenterates. It is believed that radial symmetry coelenteron, cnidoblasts, etc., disappeared and advanced characters developed to give rise to the chordates. This theory infers that chordates might have acquired higher characters independently. This theory is not acceptable.

(b) ANNELID THEORY: 

This theory suggests that the chordates have evolved from an annelid stock, like many chordates the annelids show bilateral symmetry, metamerism, head, lateral coelomate complete digestive tract, closed circulatory system, haemoglobin, etc. The Resemblance is enhanced if an annelid is turned upside down. But the mouth would be dorsal which is unlike that of chordates. Metamerism and appendages of annelids differ in nature from those of the chordates. Bilateral symmetry, head and complete digestive tract occur in other non-chordate phyla also. Coelome is schizocoelic in annelids and enterocoelic in lower chordates. Haemoglobin is dissolved in the plasma in annelids, but it is present in the red blood corpuscles in chordates. The annelid nerve cord is double and ventral in contrast to the single, hollow, dorsal nerve cord of chordates. Some striking differences exist between the annelids and the chordates in their embryology too; hence, it is difficult to accept this theory.

(c) ECHINODERM--HEMICHORDATE THEORY-ORIGIN OF

CHORDATES: This theory infers the origin of chordates, hemichordates and echinoderms from a common ancestor. This theory is based on the following evidence.

1. EMBRYOLOGICAL EVIDENCE: 

Both echinoderms and chordates have enterocoelic coelom, mesoderm and deuterostomous mouth. There is resemblance between the bipinnaria larva of certain echinoderms and the tornaria larva of hemichordates. In echinoderms chordates The central nervous system develops from a dorsal strip of ectoderm.

2. SEROGICAL EVIDENCE:

Similarity exists between the proteins of the body fluid of chordates and echinoderms. Hence the

Chordates and echinoderms are closely related. The radial symmetry of adult echinoderms will

disapprove of their relationship with the bilaterally symmetrical chordates. In echinoderms' radial

symmetry is secondarily developed from a basically bilateral symmetry. Both the primitive and

the early echinoderm larvae show bilateral symmetry.

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Mammalia :- General Characters and Unique Characters

 Class – Mammalia 

(Lt. Mamma= breast)

 Introduction: 

Mammals are the highly developed group in the animal kingdom. Mammals are the milk producing animals for sucking the young ones. They possess a covering of hair on the body, thus commonly they are also called as hairy quadrupeds. They are found in a variety of habitats-polar ice caps, deserts, mountains, forests, grasslands & dark caves. Some of them adapted to fly or live in water.The parental care and social behaviour is highly developed in mammals. About 4,100 living species are known, besides many extinct forms. 

General characters: 

1. Mammals are homeothermic (warm blooded) animals. 

2. Mammals are adapted for different modes of life such as terrestrial, aquatic, arboreal, aerial etc. 

3. The body is covered by hairs.

 4. External ears or pinnae are present. 

5. Body is divisible into head, neck, trunk and tail. The eyes have movable eye lids. 

6. The mammary glands are characteristic feature of all mammals. These glands secrete milk to suck their young ones. 

7. Teeth are usually heterodont, thecodont and diphyodont. 

8. They possess diaphragm (The upper thoracic cavity and lower abdominal cavity are separated by the layer of muscle is called diaphragm). 

9. The limbs are tetrapod and pentadactyle. The limbs are variously adapted for walking, running, climbing, burrowing, swimming or flying. The digits end with horny claws, nails or hooves. 

10. The skin is glandular containing different types of glands, namely Mammary glands (milk glands), Sudoriferous glands (sweat glands), Sebaceous glands ( oil glands), Lachrymal glands (tear glands), Scent glands, etc., 

11. The skull is bicondylar in nature.

12. Heart is four chambered. It maintains complete double circulation (systemic circulation and pulmonary circulation).

13. Presence of only a left aortic arch. RBCs are non-nucleated in all the mammals except in camel.

 14. The backbone has five distinct regions, namely cervical, thoracic, abdominal, lumbar and sacral regions.

15. Presence of dentary (Each half of the lower jaw is composed of a single bone called dentary).

16. Respiration occurs by lungs. The larynx contains well developed vocal cords for sound production. 

17. Kidneys are well developed. The ureter opens into the urinary bladder. They are ureotelic animals. The nitrogenous wastes are produced in the form of urea.

18. The nervous system consists of a highly evolved brain. Sense organs consist of well developed eyes, ears and nose. It possesses 12 pairs of cranial nerves.

19. Presence of corpus callosum (The right and left cerebral hemispheres are interconnected by the bundles of nerve fibres called the corpus callosum.).

20. sexes are separate; male has a copulatory organ penis and the female has a clitoris. Gonoducts lead directly to the outside instead of the cloaca.

21. All the mammals are viviparous except monotremes.i.e. egg laying mammals (e.g., platypus and echidna).

22. Development occurs in the uterus of the mother.

23. In the majority of the mammals, the male gonads (tests) are situated outside the abdomen in Scrotal sacs. Fertilisation is internal.

24. The embryo develops foetal membranes; hence, they are amniotes. Some of the membranes form the placenta in placental mammals.

 25. Mammals show greatest intelligence among all animals.

26. Parental care is well developed.

 Unique features of Mammalia 

1. Mammals are homeothermic (warm blooded) animals.

 2. The body is covered by hairs.

 3. External ears or pinnae are present.

 4. The mammary glands are characteristic feature of all mammals. These glands secrete milk to suck their young ones. 

5. Teeth are usually heterodont, thecodont and diphyodont. 

6. They possess diaphragm. 

7. The limbs are tetrapod and the digits end with horny claws, nails or hooves.

 8. The skin is glandular containing different types of glands, namely Mammary glands, Sudoriferous glands, Sebaceous glands, Lachrymal glands, Scent glands. etc., 

9. Heart is four chambered. It maintains complete double circulation (Systemic circulation and Pulmonary circulation).

10. Presence of only a left aortic arch. RBCs are non-nucleated in all the mammals except in camel.

 11. They are ureotelic animals. The nitrogenous wastes are produced in the form of urea. 

12. Presence of corpus callosum.

 13. All the mammals are viviparous except monotremes, i.e., egg-laying mammals (e.g., platypus and Echidna.

 14. The embryo develops foetal membranes; hence, they are amniotes. Some of the membranes form the placenta in placental mammals.

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Chordata : Characteristics features of Chordata

 PHYLUM – CHORDATA 

(Gr. Cord = string; ata bearing) 

Introduction: The organisms which bear a stiff supporting rod-like structure along the back called a notochord at some stage of their lives. Chordates have three important common features, namely the presence of a notochord, a dorsal tubular nerve cord and pharyngeal gill clefts. The phylum contains about 65,000 existing (living) and 25,000 extinct species. Existing species inhabit land, water or air throughout the world. Fish, frogs, lizards, snakes, birds, rats, domestic animals, man, etc., are a few examples of common chordates. Generally, chordates are relatively larger and better organised than other metazoans (i.e., nonchordates). The representatives of this phylum exhibit great diversity in their size, habits, habitats, anatomy, physiology, etc. These animals probably originated prior to the Cambrian period, but there is considerable controversy regarding their origin.

 General Characters:

1. Presence of notochord: It is a rod-like supporting structure and located below the nerve cord and above the alimentary canal. It may either persist throughout life (e.g., in lampreys) or it may be replaced partially or completely by the vertebral column.

2. Presence of dorsal tubular nerve cord: It is a hollow tube filled with fluid and dorsal in position. It lies above the notochord and outside the coelom. It persists throughout life in most of the chordates, but in a few it degenerates before maturity.

3. Presence of pharyngeal gill clefts: Gills are the respiratory structures. Gill clefts are the paired openings leading from pharynx to the exterior. The gills are found throughout the life in fishes, but in amphibians the gills appear only in larval stages; later the gills become degenerate during the adult stages.

4. They are aquatic, aerial or terrestrial. All are free-living with no fully parasitic forms. 5. Bilateral symmetry: In chordates, the formation of two equal body parts when we cut the body in only one plane from the central axis.

6. Metamerically segmented body: The body is metamerically segmented. Externally, the segmentation is less distinct.

7. Ventral heart: The heart is ventral in position.

8. Closed type of circulatory system: RBCs are suspended in the plasma. Haemoglobin is the respiratory pigment in the RBCs.

9. Triploblastic animals: The body wall is made up of three germinal layers, namely outer ectoderm, middle mesoderm and an inner endoderm.

10. Hepatic portal system: The food-laden blood from the alimentary canal is carried to the liver through a hepatic portal vein.

11. Paired appendages: In all vertebrates, pectoral and pelvic girdles are present. These are paired in number, and in some animals it may be modified. Ex. fishes, frogs, reptiles, birds and mammals.

12. Post-anal tail: A post-anal tail usually projects beyond the anus at some stage and may or may not persist in the adult.

13. Endoskeletons may be cartilage or bony.

14. Digestive system complete with digestive glands.

15. excretory system includes protonephric, mesonephric or metanephric kidneys.

16. Exoskeleton well developed in most of the vertebrates.

17. Nervous system consists of a dorsal and tubular nerve cord which, at the anterior end usually enlarged to form a brain.

 18. Sexes are separate and development is direct with few exceptions.

Unique features of Chordates 

1. All chordates possess a notochord. It is an elastic, solid skeletal supporting rod. It runs along the long axis of the body below the nerve cord and above the alimentary canal. It persists throughout life in some primitive chordates. In higher forms it is replaced by a vertebral column (backbone).

2. A dorsal tubular nerve cord is present in all chordates. It is placed dorsal to both the alimentary canal and notochord. The anterior part of the nerve cord is modified into a brain.

3. A series of paired Pharyngeal gill clefts are present on the side walls of the pharynx. The gill slits persist throughout the life in fishes. In amphibians, they are present only in the larval stages. In reptiles, birds and mammals, the gill slits make their appearance only in the embryonic stages and are non-functional.

4. The endoskeleton, a post-anal tail and a ventral heart are the other unique characters.

5. They are bilaterally symmetrical, triploblastic, eucoelomate with organ system levels of organisation.

 6. The body is differentiated into head, trunk and tail.

 7. Organ systems are well developed.

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Important MCQs based on phylum and Classification

 Here are  multiple-choice questions along with their answers and detailed explanations:

Question 1. Which of the following traits is NOT a main trait of Aves or Reptilia but rather exclusive to mammals?

A) Amniotic egg
B) Endothermy (warm-bloodedness)
D) Glands mammary
D) Mammary glands
Answer: D) Mammary glands
Explanation .
Amniotic eggs: Reptilia and Aves both lay amniotic eggs (eggs with a protective membrane and yolk). Although most animals have lost the shelled egg and grow their young inside, their forebears also had amniotic eggs and they keep the amnion during embryonic development.
Endothermy: Aves are entirely endothermic. Most are ectothermic (cold-blooded), however certain reptiles can show a little endothermy (like leatherback sea turtles). Mammals are also warm-blooded. So, both birds and animals have this quality.
Presence of scales (at least in some form): Reptiles are well-known for their scaly skin. Birds' feet and legs are scaled. Some animals, like pangolins, also have scales. So, this is not a unique trait of mammals.
A defining and distinguishing feature of all animals, mammary glands are those that provide milk to feed their offspring. Birds and reptiles lack actual mammary glands.

 
Question 2. Which of the following characteristics is a major adaptation enabling Aves (birds) for flight and is not usually present in Reptilia or Mammalia in the same specialised form?

A) Lung presence for breathing 

B) Four-chambered heart 

C) Air sac and lightweight skeleton
D) Fertilisation inside the body
Answer. C) Lightweight skeleton with air sacs

Explanation
Though the form and efficiency may differ, all three groups—Mammalia, Aves, Reptilia—have lungs for respiration.
Both mammals and birds have four-chambered hearts, which help them completely separate oxygenated from deoxygenated blood, hence sustaining their high metabolic rates. Most reptiles have a three-chambered heart; some, like crocodiles, have a four-chambered heart.
Birds have a very particular skeletal architecture suited for flight: lightweight skeleton with air sacs. Often hollow, their bones are packed with air sacs, extensions of the respiratory system. This offers structural support and helps in effective breathing, thus much lowering their weight. Although certain reptiles have air holes in bones and mammals have air-filled sinuses in the skull, neither species has the large network of air sacs linked to a lightweight, hollow skeleton typical of birds.
Mammals, birds, and many reptiles undergo internal fertilisation. For flying, it is not a characteristic exclusive to birds.

Question 3. Which of the following is a characteristic feature commonly observed in Reptilia but not typically found in Mammalia or Aves?

A) Metabolism of endothermic
B) Laying amniotic eggs on land

C) Presence of hair or fur

D) Parental care of offspring

Answer: B) Laying shelled eggs on land (amniotic eggs)

Explanation:

Endothermic metabolism: Birds and mammals are mostly endothermic. Most reptiles are ectothermic, depending on outside heat to control their body temperature.
Laying shelled eggs on land (amniotic eggs): While mammals evolved from amniote ancestors, most extant mammals are viviparous (give birth to live young) and have lost the shelled egg. Though they are different from the leathery or hard-shelled eggs deposited by most reptiles, birds lay shelled amniotic eggs. Reptiles are defined by depositing amniotic eggs on land with a leathery or hard shell.
Hair or fur is a distinguishing trait of mammals; it is not present in reptiles or birds; birds have feathers, which are structurially different.
Parental care of children: All three categories show different degrees of parental care. While many mammals show great parental care, certain reptiles display parental care. Birds are well-known for their nesting habits and caring for their offspring. So, it is not a quality exclusive to reptiles.

Question 4 . Which of the following key traits is present in all Chordates at some point in their life cycle but lacking in Non-Chordates?
A) A genuine coelom (body cavity)
B) Bilateral symmetry
C) A post-anal tail
D) Triploblastic organization
C) A post-anal tail
Answer . A post anal Tail
Explanation
A true coelom (body cavity): A true coelom is present in many Non-Chordates (e.g., annelids, mollusks, arthropods) as well as all Chordates. Therefore, it is not a distinguishing feature of Chordates alone.
Bilateral symmetry: Bilateral symmetry is a common feature in many Non-Chordates (e.g., platyhelminthes, nematodes, annelids, arthropods) and all Chordates. Thus, it doesn't uniquely define Chordates.
A post-anal tail: A post-anal tail, a muscular tail extending beyond the anus, is a defining characteristic of Chordates at some point in their development (though it may be reduced or absent in the adult stage of some groups, like humans). This feature is absent in Non-Chordates.
Triploblastic organization: Triploblastic organization (having three germ layers: ectoderm, mesoderm, and endoderm) is a characteristic shared by all Chordates and many Non-Chordates (from flatworms onwards).
Question 5: Vertebrata is a subphylum within the Phylum Chordata. Which of the following features is a defining characteristic of Vertebrates that distinguishes them from other Chordate groups (like Urochordata and Cephalochordata)?

A) Presence of a notochord
B) Dorsal hollow nerve cord
C) Pharyngeal gill slits
D) A vertebral column (backbone)
Answer: D) A vertebral column (backbone)

Explanation:

Presence of a notochord: A notochord, a flexible rod providing skeletal support, is present in all Chordates at some stage. In Vertebrates, the notochord is typically replaced by or surrounded by a vertebral column during development.
Dorsal hollow nerve cord: A dorsal hollow nerve cord is another key characteristic of all Chordates. In Vertebrates, this nerve cord develops into the brain and spinal cord.
Pharyngeal gill slits: Pharyngeal gill slits are present in all Chordates at some point in their life cycle. In aquatic Vertebrates, these develop into gills. In terrestrial Vertebrates, they are modified into other structures during embryonic development.
A vertebral column (backbone): The vertebral column, a series of bony or cartilaginous vertebrae that provide support and protect the dorsal nerve cord, is the defining characteristic of Vertebrates. This replaces or surrounds the notochord and provides a more rigid and complex skeletal structure.

Question 6: Which of the following animal groups is classified under Non-Chordata?

A) Fish
B) Amphibians
C) Insects
D) Reptiles
Answer: C) Insects

Explanation:

Fish: Fish belong to the subphylum Vertebrata, which is within the Phylum Chordata. They possess a vertebral column.
Amphibians: Amphibians also belong to the subphylum Vertebrata within the Phylum Chordata. They have a vertebral column.
Insects: Insects belong to the Phylum Arthropoda, which is a major phylum within the Invertebrates (Non-Chordata). They lack a notochord and a vertebral column.

Reptiles: Reptiles belong to the subphylum Vertebrata within the Phylum Chordata. They possess a vertebral column.

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Chapter 03 Materials and methods Part 05 Materials and equipment needed for experimantal research

 This is an exhaustive inventory of **equipment necessary for aquarium and laboratory configuration** for executing **ichthyological research**, specifically in nutritional, physiological, and toxicological investigations.

## 🐟 **A. Aquarium Setup Apparatus**

### **1. Aquariums and Equipment**

* Glass or acrylic aquaria (different capacities: e.g., 50–100 L) * Tank supports or shelving units * Aquarium coverings or lids * Dividers (for partitioning or isolation inside aquaria)

### **2. Hydric Management**

* Water storage tanks (for aged or dechlorinated water)
* Water conditioner/dechlorinator * Submersible water pumps (for circulation purposes)
Air pumps and aeration stones
Airline tubing and valves
* Filtration systems (sponge filters, canister filters, etc.)
* Thermometers (digital or mercury-free analog) * Heaters or chillers (according to species temperature needs)
* Syphon hoses (for maintenance and water alterations)
* Receptacles and vessels (for water management)

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## 💧 **B. Instruments for Monitoring Water Quality**

* Digital pH meter or pH testing kits * Dissolved Oxygen (DO) meter * Ammonia, nitrite, and nitrate testing kits * Total Dissolved Solids (TDS) meter * Conductivity meter * Salinity refractometer (for brackish or marine species)
* Test kits for water hardness (GH/KH) * Thermo-hygrometer for laboratory environment monitoring

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## 🍽️ **C. Nutritional Administration and Dosage Preparation**

Analytical balance (precision: 0.001 g or superior)
* Mixing basins and spatulas (stainless steel or glass) * Gelatin or agar for binding feed
* Pelletiser or manual extruder * Drying trays or dehydrator * Refrigerator (for feed storage)
* Syringes and pipettes (for liquid dosage preparation or injection) * Blenders and homogenisers (for mixing feed or dosing solutions)

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## 🧪 **D. Laboratory Equipment**

Digital weighing scale for measuring fish body weight
Digital callipers (for measuring the length of fish)
Dissection instruments (forceps, scissors, scalpels)
Dissection tray and board
* Centrifuge (for the processing of blood or tissue samples)
* Compound and stereo microscopes * Spectrophotometer for biological experiments
* Microplate reader (optional, for ELISA or enzymatic activity)
pH strips and buffer solutions for calibration
Sample vials and test tubes (glass or polypropylene)
Laboratory glassware (beakers, flasks, graduated cylinders)

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## 🧬 **E. Discretionary Instruments for Enhanced Analysis**

* Histological apparatus (fixatives, microtome, staining kits) * Haematological collecting apparatus (capillaries, anticoagulant vials)
Freezer (at -20°C or -80°C for sample preservation)
* Data recording/statistics software (Excel, SPSS, R) * Image analysis software (if employing microscope)

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## 🧯 **F. Safety and Maintenance**

First aid kit, lab coat, gloves, goggles, fish anaesthetics (e.g., MS-222 or clove oil), fire extinguisher, spill kits, and disinfectants (e.g., potassium permanganate, chlorine).

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## 📋 **G. Documentation and Labelling**

* Permanent markers and weatherproof labels * Logbooks for tank data, water quality, feeding, and mortality * Laminated charts for daily monitoring sheets

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### ✅ **Discretionary Components for Automation and Expansion**

Automatic feeders (for scheduled feeding)
* Automated water exchange system * Closed-circuit television or webcams (for remote surveillance) * Barcode system (for sample monitoring)

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Would you like this list in a printed checklist format or as a spreadsheet for purchase planning?

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Chapter 03 :- Materials and Methods Part 04 Techniques for Administering Experimental Doses to Fish

  Techniques for Administering Experimental Doses to Fish

**1. Overview**
In ichthyological research, the administration of experimental doses—such as nutrients, pharmaceuticals, toxins, probiotics, or protein supplements—is an essential component of experimental design. The selected approach must guarantee precise and uniform dosing while reducing stress to the fish. This document delineates the predominant and scientifically validated methods for administering dosages to fish in laboratory settings.

 **2. Prevalent Techniques for Dose Administration**

*A. Oral Administration via Feed (Most Favoured for Nutritional Research)

**Method**: The substance (e.g., egg albumin protein) is incorporated into the feed and administered to fish as a component of their regular diet.

**Benefits**:

* Natural method of administration. * Appropriate for longitudinal investigations. * Minimal stress and manipulation. * **Procedure**:

1. Formulate feed incorporating the test material (e.g., 5%, 10%, 15% egg albumin by weight).
2. Utilise gelatin or agar to create pellets or paste.
3. Dehydrate or refrigerate and provide at a consistent dosage (e.g., 3% of body weight each day).

 **B. Oral Gavage (Forced Feeding)

**Method**: A precise dosage is administered straight into the stomach using a tiny feeding tube or syringe.

**Benefits**:

* Accurate dosage administration. Beneficial for brief investigations or for evaluating limited quantities of costly substances. * 

Drawbacks:

* Stressful for fish. * Risk of damage or aspiration. * **Use Case**: Single-dose pharmacokinetics or acute toxicity assessment.

 **C. Immersion/Bath Exposure

**Method**: Fish are subjected to the test material solubilised in water.

**Benefits**:

* Optimal for hydrophilic compounds (e.g., pharmaceuticals, poisons, stressors). * Convenient for simultaneous application to several subjects. * 

**Drawbacks**:

* Diminished control over individual dosage consumption. Absorption differs among species and conditions. * **Application**: Environmental toxicity or research on stress responses.

**D. Injection (Intraperitoneal/IP or Intramuscular/IM)

**Method**: The dosage is administered via direct injection into the body.

**Benefits**:

* Exceptional precision and rapid absorption. * Beneficial for vaccinations, hormones, and pharmaceutical research. * **Drawbacks**:

* Elevated stress levels and increased susceptibility to infection. Demands anaesthesia and specialised expertise. * **Application**: Hormonal induction, immunisation experiments, assessment of therapeutic effectiveness.

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**3. Choosing the Appropriate Method**

| Type of Study | Preferred Method | ------------------------- | 

| Nutritional studies | Dietary oral administration | 

| Pharmacokinetics | Oral gavage or injection | 

| Toxicity (acute/chronic) | Immersion or oral administration | 

| Vaccine trials | Injection (intraperitoneal or intramuscular) | 

| Probiotic/supplement trials | Oral administration |

**4. Dosage Calculation for Feed-Based Research**

**Illustration (Egg Albumin Research)**:

* Desired dose: 10% egg albumin in feed
* Daily feed ration: 3% of body weight
* Fish weight: 10 g
* Feed per day = 10 g × 3% = 0.3 g
* Egg albumin in feed = 10% of 0.3 g = **0.03 g egg albumin/day per fish**

Prepare and pellet the feed appropriately.

* Adhere strictly to protocols for animal welfare and ethical dosage thresholds.
* Minimize handling and stress during administration.
* Monitor fish closely for adverse reactions post-dosing.

The method of dose administration in fish research should align with the **study objective**, **compound type**, and **fish welfare**. For nutritional experiments like protein supplementation with egg albumin, **oral feeding via modified diet** is the most suitable and least invasive method.

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Chapter 03 :- Methods and Materials Part 03 Categorisation of Fishes into Control and Treatment Groups for Experimental Research

  Categorisation of Fishes into Control and Treatment Groups for Experimental Research

In experimental aquaculture and fish nutrition research, the accurate categorisation of fish into control and treatment (dose) groups is crucial for obtaining reliable, repeatable, and statistically valid outcomes. This document delineates standardised protocols for categorising fish into groups according to experimental treatments, emphasising consistency, reproducibility, and ethical management.
To methodically assign fish to control and treatment groups to assess the impact of nutritional interventions (e.g., varying concentrations of natural protein sources like egg albumin) on growth, survival, and health.

 
Criteria for Classification

* **Species**: Choose a consistent species appropriate for the experimental aim.
* **Age and Size Homogeneity**: Utilise fish from the same age cohort with comparable beginning body weight and length to reduce variability.
* **Acclimatisation**: Acclimatise all fish for a duration of 7 to 10 days under laboratory settings prior to group allocation. Classification Method

| Group ID | Treatment Type | Egg Albumin in Feed (%) | 

 | G1 | Control | 0% | Standard feed, devoid of albumin | 

| G2 | Low Dose | 5% | Low concentration of albumin | 

| G3 | Medium Dose | 10% | Moderate concentration of albumin | 

| G4 | High Dose | 15% | High concentration of albumin | 

| G5 | Very High Dose | 20% | Assessment for potential toxicity |

* **Replication**: Each group must consist of **a minimum of 3 replicates**, maintained in distinct tanks (e.g., 3 tanks per group × 5 groups = 15 tanks in total).
* **Fish per Tank**: Ensure same stocking density in all tanks (e.g., 10 fish per tank).

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 Randomisation and Allocation Methodology

* **Step 1**: Individually weigh and measure every acclimatised fish.
* **Step 2**: Organise fish by weight to guarantee consistency in size across groups.
* **Step 3**: Randomly allocate fish to tanks with a lottery system or a computer-generated randomisation list to eliminate bias.
Clearly label tanks with the group ID and replicate number (e.g., G1-R1, G1-R2, G1-R3).

* Ensure uniform environmental parameters (temperature, aeration, light cycle, and water quality) throughout all tanks to guarantee that treatment is the sole variable.

* Adhere to institutional and national regulations on animal welfare and utilisation .

* Prevent overcrowding and observe for signs of aggressiveness or stress following grouping.

* Preserve a **grouping log sheet** comprising:

* Fish Identification * Group and duplicate assignment * Initial weight and length measurements * Tank designation

The systematic and impartial categorisation of fish into control and dosage groups is a fundamental step in experimental ichthyological study. Maintaining homogeneity within and across groups, implementing random assignment, and ensuring sufficient replication bolster the scientific validity and ethical integrity of the study.

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Chapter 03 :- Materials and Methods Part 02 Management of Aquaria in Laboratory After Fish Procurement

 Management of Aquaria in Laboratory Following Fish Procurement

1. Introduction

Effective administration and care of aquaria post-fish acquisition are crucial for ensuring animal health, reducing stress, and establishing baseline conditions for scientific research. This document delineates the protocols and optimal techniques for acclimating fish and sustaining aquaria under laboratory settings following acquisition.

2. Fish Acclimatisation

Quarantine Protocol: All newly acquired fish must be subjected to a quarantine duration (often 14–30 days) in a distinct, isolated system to observe for indications of disease and avert pathogen spread.

Gradual Acclimation: Methodically acclimatise fish to the laboratory water temperature, pH, and salinity over a duration of 30–60 minutes with drip or stepwise mixing techniques to prevent osmotic shock.

Observation: Assess fish behaviour, eating patterns, and overall health within the initial 24–48 hours. Document any indications of illness, irregular movement, or atypical breathing.

3. Monitoring of Water Quality

* **Initial Testing**: Assess water parameters (pH, temperature, dissolved oxygen, ammonia, nitrite, nitrate, hardness) promptly upon fish introduction and everyday for the initial week.

* **Stabilisation**: Confirm that biological filtration is developed and operational to facilitate nitrogen cycling. Introduce nitrifying bacteria if necessary.

4. Maintenance and Sanitation of Tanks

* **Cleaning Schedule**: Implement a consistent cleaning regimen. Eliminate uneaten food, excrement, and detritus without disturbing the fish.

* **Aquatic Alterations**: Conduct partial water changes (10–25%) at consistent intervals (e.g., weekly), utilising pre-conditioned water to sustain ideal conditions.

**Disinfection Protocols**: Sanitise equipment (nets, syphons) between tanks to avoid cross-contamination. Utilise gentle, fish-safe disinfectants and ensure thorough rinsing.

5. Nutritional Administration

* **Dietary Adjustment**: Provide modest, readily digested foods during the initial days following arrival. Systematically shift to the experimental or maintenance diet.

* **Feeding Frequency**: Administer food 1–2 times daily in minimal quantities to avert overfeeding and deterioration of water quality.

6. Behavioural and Health Surveillance

* **Routine Inspections**: Monitor fish a minimum of times daily for indications of illness (e.g., lesions, fin rot, atypical swimming), stress (e.g., concealment, colour deterioration), or aggressiveness.

* **Record Keeping**: Document water parameters, feeding behaviour, mortality rates, treatments, and any significant findings.

7. Disease Management

* **Isolation of Affected Fish**: Promptly relocate diseased fish to a hospital or quarantine tank for therapeutic intervention.

Veterinary Consultation: Obtain specialised diagnostic and therapeutic alternatives for undiagnosed or chronic infections.

Implement preventive measures by upholding hygienic standards, minimising handling, and avoiding excessive inventory to mitigate illness risk.

8. Stress Reduction

**Environmental Enrichment**: Furnish shelters, vegetation, or substrates to alleviate stress and replicate natural habitat conditions where suitable.

* **Minimal Disturbance**: Restrict superfluous access to the tank, abrupt movements, and auditory disruptions within the laboratory setting.

9. Adherence to Compliance and Ethical Standards

All handling practices must comply with institutional animal care regulations and conform to national and international criteria . Guarantee that all staff are proficient in fish handling and welfare protocols.

10. Conclusion

The post-procurement management of fish in laboratory aquaria necessitates meticulous consideration of acclimatisation, water quality, and animal health. Establishing standard operating methods for tank hygiene, monitoring, and maintenance facilitates consistent research results and upholds superior animal welfare standards. 

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Chapter 03 : MATERIALS AND METHODS Part 01 Setting up aquaria for carrying research on fishes

 Setting up aquaria for the purpose of doing research on fishes:- 

1. Introduction
To ensure the validity of the experiment, the well-being of the animals, and the repeatability of the results, it is necessary to carefully design the establishment of aquaria for fish research. In order to prepare aquariums for scientific research involving different kinds of fish, this note provides an overview of the most important stages and concerns.


2. Experimental Design and considerations
Establishing the study objectives (such as behaviour, physiology, and toxicity) is a necessary step before establishing aquariums. The decisions that are made regarding tank dimensions, water conditions, illumination, and stocking densities will be influenced by this. Make sure that all of the protocols are in accordance with the ethical principles and the criteria set out by the institutional animal care and use committee (IACUC).

3. The Specifications of the Tank
Size and Material: Tanks should be of a size that is adequate for the species and the number of animals that are contained within them. Both glass and acrylic are popular materials, with acrylic being more readily available because to its reduced weight and superior insulating property.
For the purpose of conducting controlled experiments or preventing aggressiveness, the tank layout should include the provision of partitions or isolated sections. In the event that behaviour is being examined, ensure that hiding places or environmental enrichment are included.

4. Management of Water Quality
* **Source Water**: Make use of water that has been dechlorinated from the tap, water that has been filtered by reverse osmosis, or a mix of these two that has been adjusted for ionic content.
The installation of biological, mechanical, and chemical filtration devices is included in the filtering process. When it comes to preserving nitrogen cycling, biological filters are absolutely necessary.
For aeration, you can use air stones or diffuser to keep the amounts of dissolved oxygen at a consistent level.
* Temperature Control: Install heaters or chillers to maintain a consistent temperature, being sure to take into account the species in question.
Water parameters include pH, ammonia, nitrite, nitrate, salinity (if the water is marine), and hardness. These should be monitored on a regular basis. Keep within the limits that are particular to the species.

5. Lighting and the number of photo-periods 

Light has the ability to impact both behaviour and physiology, hence it is important to have programmable lighting systems that can imitate natural photo-periods (for example, a light-dark cycle of 12:12).

6. Acclimatization and Stocking of Supplies

It is important to progressively acclimatize fish to the surroundings of the aquarium in order to reduce stress. To avoid the spread of illness, fresh specimens should be placed in quarantine for a period of at least two weeks. Maintain stock tanks according to the social behaviour of the species in question and the acceptable densities.

7. Maintenance and Feeding of the Animals

Diets that are suitable for the species should be fed at regular intervals. In order to prevent fouling, remove any food that has not been consumed.
* In order to keep the water quality in good condition, do partial water changes (for example, 10–20% weekly).
* Document in great detail the characteristics of the water, the food, and the health of the fish.

8. Monitoring and Keeping Records of Observation

It is important to keep an eye out for any symptoms of stress, disease, or abnormal behaviour in fish. Keep meticulous journals of all the ambient variables, feeding regimens, and observations that are pertinent to the research pertaining to the animals.

9. Compliance with Ethical Standards and Regulatory Rules

* Ensure that housekeeping and handling processes are in accordance with national and institutional norms.
* Stress and discomfort should be kept to a minimum, and techniques of anaesthesia and euthanasia should be authorised for the species.

10. A fish research system that is well-maintained and well-maintained system is  essential for credible and repeatable fish research. The health of the animals and the reliability of the scientific data may be protected by paying attention to the ambient circumstances, the requirements that are special to the species, and ethical specifications.

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Dissertation Writing :- Acknowledgement

 Its gives me great pleasure to record my deep sense of gratitude to ...............  (HOD) Department of Zoology, ................... College,................ for her constant encouragement, able guidance and valuable suggestions.  Her kind supervision  and inspiration is the outcome of this work. 

I am thankful to following faculty members.  .............................. Department of Zoology, ... College,......  

I would also like to show our gratitude to Reseach Scholars Neha Manjari and Diksha Bhanu for giving us their percious time and better understanding of research and scientific journaling tirelessly. 

At last but not the least I am thankful to my parents who made me able to open my  eyes in this world and reach up to this stage by booms and graces, without whom this work would not have been completed.

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Dissertation writing :- Declaration by Student

  I  declare  that  the  dissertation  entitled  ..............................................................  is  my  own  work  conducted  under  the supervision of ......................................... .  

 I further declare that this written submission represents my ideas in my own words and where others' ideas or words have been included, I have adequately cited and referenced the original sources. I also declare that I have adhered to all principles of academic honesty and integrity and have not misrepresented or fabricated or falsified  any idea/data/fact/source in my submission.

 I understand that any violation of the above will be cause for disciplinary action by the University and can also evoke penal action from the sources which have thus not been properly cited or from whom proper permission has not been taken when needed.

                                                                                       STUDENTS NAME AND SIGN

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A Comprehensive Guide to Writing the Most Effective Dissertation for Students Pursuing a Postgraduate Degree in Zoology

 

The following is a complete tutorial that explains how to create the best dissertation for a postgraduate student who is in their last semester of Zoology that includes pictures . Structure, planning, writing advice, and examples that are especially geared to Zoology are all elements that are covered in this tutorial --- ---

# 🧬 A Comprehensive Guide to Writing the Most Effective Dissertation for Students Pursuing a Postgraduate Degree in Zoology

This is the first step in comprehending the objective of a dissertation.

The term "dissertation" refers to an academic paper that is based on study and provides original results or covers in-depth themes related to your research field. In the field of Zoology, this can include subjects such as:

The following fields of study are included: animal physiology, ecology and conservation, evolutionary biology, taxonomy and systematics, wildlife biology, genetics and molecular zoology, and evolutionary biology.

Displaying your comprehension, research skills, and capacity to make a contribution to the field of Zoological science is the objective.

## 🗂️ 2. The standardised structure of the dissertation

To illustrate, this is the standard arrangement, with comments centred on Zoology:

| Section | Description | | ------------------------- | ----------------------------------------------------------------------------------------- On the title page, you should include your name, registration number, university, department, and the title of the project. On the abstract page, you should include a description of your objectives, methodology, important findings, and conclusions that is between 250 and 300 words long. I would want to express my gratitude to my supervisors, universities, funding agencies, and everyone who have contributed to this project. 

 The table of contents is as follows: 

 | Auto-generated with chapter and sub-section titles. 

|| **Introduction** | Background on the zoological topic, importance, hypothesis, and objectives.

 | | **Review of Literature** | Summarise and critically analyse previous research relevant to your topic. | | **Materials and Methods** | Explain your study site, species, experimental setup, equipment, and statistical methods. 

|| **Results** | Use tables, graphs, and charts to present findings. Stay away from interpretation here. The discussion will consist of interpreting the findings, comparing them to other research, and explaining the importance of the findings. |

 | **Conclusion** | Provide a summary of the results and make recommendations for further research or conservation implications. | 

| **References** | Use correct citation (APA, MLA, or university-specified style). |

| **Appendices** | Include raw data, questionnaires, maps, or ethical approval letters. |

3. Make a course of action for your dissertation.

##✅ ### Take Care in Selecting a Subject

* Choose a subject that you are enthusiastic in and that is reasonable in terms of both time and breadth. * Align it with the most recent research trends or the requirements for conservation.

* Have a conversation with your boss about possible subjects.

##✅ ### Construct a timeline.

To keep track of the tasks, you need make a Gantt chart (I can make one for you if you need it).

| Week | Task | | ----- | **--------------------------------------------------- | | 1–2 | Topic finalisation & proposal writing | | 3–6 | Literature review | | 7–14 | Field/Lab work | | 15–18 | Data analysis | | 19–22 | Writing chapters | | 23–24 | Editing and submission |

--- ---

[## ✍️] Guidelines for Writing

Be clear and concise in your answers: If it is not specified, avoid using too technical language.

"We observed thirty birds..." is a more accurate statement than "thirty birds were observed." 

* Make use of active voice. 

Use scientific names, such as "Panthera tigris," rather than just using the word "tiger."

* **Consistency in Tense**: 

**When discussing procedures and findings, use the past tense. When discussing known facts and conversation, use the present tense.

--- ---

The fifth point is the presentation of data and illustrations.

In Zoology Dissertations, the Most Important Visuals Consist of:

Please provide the following: * Photographs of species, habitats, or experimental setup * Maps (for distribution or field locations) * Graphs (Bar, Line, and Pie – for the frequency of behaviour, population density, and other measures)

* Tables (with a list of species, morphological characteristics, and condensed versions of the data) * Charts (for comparing or analysing trends)

Would it be possible for me to create some sample drawings, such as a map depicting the distribution of species or a chart displaying behavioural patterns?

--- ---

6. Common topics for dissertations in the field of Zoology

The behavioural study of the macaca mulatta in urban parks, the comparative study of insect biodiversity in agroecosystems and forest ecosystems, the use of DNA barcoding for the identification of freshwater fish, and the impact of urbanisation on the variety of amphibians are all examples of interesting research projects. Control of Reproductive Behaviour in Lizards and Its Relation to Hormones

--- ---

The final checklist is available.

Prior to submitting, make sure that:

* [] Each and every page has been numbered and structured appropriately * [] All references are comprehensive and formatted in a consistent manner * The data is correct, double-checked, and presented in an organised manner. ] [] No instances of plagiarism (please use a plagiarism checker) You have either proofread or had your work evaluated by other people. You have complied with the rules for the dissertation published by your university.

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Class Aves—Birds General Characters

  Class Aves—Birds 

Approximately 9,100 species 

o This class comprises the birds, which are vertebrates adapted for aerial life.

 o The body is divided into head, neck, trunk, and tail.

 o Their internal and external structures are modified to suit the process of flight. 

o There are several exoskeletal structures, which are the feathers covering the greater part of the body, the horny scales covering the feet, the claws found at the tips of the digits, and the horny beaks covering the bony beaks. All of these structures are epidermal in origin.

 o The forelimbs are modified into wings, which are used for flight. They are moved by the chest muscles, which are very well developed.

 o They move on land by hind limbs.

 o Many trunk and tail vertebrae, as well as some bones of the fore and hind limbs, are fused, giving compound, compact bones more suitable for flight.

 o The bones are generally provided with air spaces. 

o The two clavicles unite to form a furcula, and the sternum has a ventral keel in flying birds.

 o The skull is produced anteriorly into upper and lower beaks carrying no teeth, and posteriorly it carries a single occipital condyle.

 o The skin possesses a single gland lying dorsally at the base of the tail and known as the oil gland. 

o The alimentary canal includes a crop, which is a wide sac used for temporary storage of food, and a gizzard, which is a thick-walled, muscular part of the stomach used in grinding hard food materials. 

o The heart consists of four chambers, which are two auricles and two ventricles. 

o There is only one aortic arch, which is the right one.

 o There is a special organ of voice, the syrinx, lying at the base of the trachea. 

o The lungs are connected with air sacs, which are connected with the spaces inside the bones.

 o The urinary bladder is absent, and excretory materials are semisolid. 

o In females, there is a single left ovary and left oviduct; the right elements are usually atrophied. 

o Fertilization is internal, and the eggs are large, rich in yolk, and enclosed by hard calcareous shells.

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CHORDATA :- A brief Introduction

 

Phylum CHORDATA (Gr., chorda, a string, or L., chordatus, a chord, i.e., the notochord) is the largest of the deuterostome phyla. It is the highest and the most important phylum, comprising a vast majority of animals living and extinct, such as tunicates, lancelets, lampreys, fishes, amphibians, reptiles, birds, and mammals, including man.

Characters

All chordates are bilaterally symmetrical, with 3 germ layers, a segmented body, complete alimentation, and a well-developed coelom. While groups of chordates differ widely from each other, they, however, possess three outstanding common characters that separate them from non-chordates.  These three fundamental common chordate traits are as follows :

1. Notochord (Gr., noton, back; chorde, cord).  It is a slender, longitudinal, stiff skeletal rod of connective tissue cells present just dorsal to the digestive tract. It is this structure that gives the phylum its name. It furnishes support to the body and is not to be confused with the nerve cord. It persists throughout life in the lower chordates, such as urochordates, cephalochordates, and cyclostomes. But in the higher chordates (fishes to mammals), it is present only in the embryos and later replaced by the vertebral column, which is made up of different vertebrae.

2. Hollow dorsal nerve cord. A hollow or tubular nerve cord is present, extending lengthwise of the body dorsal to the notochord. It arises as an infolding of the dorsal surface ectoderm of the embryo.

3. Pharyngeal gill-clefts.  Paired lateral openings, commonly referred to as gill clefts or gill slits, develop on the sides of the embryonic pharynx, leading to the outside. They persist in all lower chordates and serve for aquatic pharyngeal

respiration. In higher chordates they soon close before hatching or birth as the adults of these animals develop lungs for breathing air.

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B.Sc. Sem II :- Aves :- Flight Adaptations in Birds

 

FLIGHT ADAPTATIONS IN BIRDS

INTRODUCTION

 The adjustments on the part of the animal in a particular surrounding to become efficient in locomotion, in securing sufficient food, and in getting good shelter are called adaptations to the particular environment.

 The birds have taken to aerial life, and all the changes that have taken place in accordance with this mode of life are called volant adaptations.

 Practically almost all the body organs have been modified to cope with the new environment.

 These modifications led Young (1958) to describe birds as “masters of the air”.

A. MORPHOLOGICAL ADAPTATIONS

1. Shape:

 The streamlined, spindle-shaped body offers the least resistance during passage through air.

2. Compact body:

 The high location of light organs like lungs and air sacs and low positions of heavy muscles, sternum, and digestive organs shift the center of gravity lower.

 This arrangement prevents the turning over of the body in air.

 Further, the disposition of wings high upon the thorax helps in maintaining balance in the air.

3. Mobile neck and break:

 The two toothless jaws are produced into a beak, which helps in preening, feeding, nest building, offense, defense, etc. To perform these efficiently, the neck has elongated and flexible.

4. Bipedal locomotion:

 To bear the weight of the body and move on the ground, hind limbs shifted slightly forward on the thorax and became stouter.

5. Flight organs:

 Forelimbs are modified into wings, which are the sole organs of flight.

 The surface area of the wings is increased by the development of elongated remiges (flight feathers).

 These feathers form a broad, continuous surface for striking the air in flight and supporting the bird in the air.

6. Feathers:

 The body is fully covered with closely fitted and backwardly directed contour feathers.

 These make the body streamlined and reduce the friction of air.

 The blanket formed by feathers holds a certain amount of air between the body and the feather covering.

 The air helps buoyancy.

 Feathers also help in maintaining body temperature as they are of a non-conducting nature.

7. Integument:

 The loose attachment of skin over the body is also a modification for flight.

 It provides extensive movement of the skeletal musculature.

8. Short tail:

 Rectrices (caudal feathers) are arranged in a fan-like fashion as a series on a short muscular tail.

 These assist in steering, to sudden check flight, and as a counterbalance in perching.

9. Perching:

 The phenomenon of holding of twig automatically while sitting by birds with the help of hind limbs is called perching.

 For this, the muscles of the hind limbs are developed in such a fashion that when a bird sits on a branch of the tree, the toes close round the twig automatically.

 It is so because the settling of the bird on the twig puts the flexor tendons on the stretch; with the exertion of the pull, the toes are bent spontaneously around the perch.

 A bird can go to sleep on a perch without any fear of falling.

B. ANATOMICAL ADAPTATIONS

1. Flight Muscles:

 The twig is operated by a set of well-developed muscles called flight muscles.

 These included

(i) Pectoralis major causing downward stroke

(ii) Pectoralis minor effecting upstroke.

(iii) Corachobrachialis and coracohumerals bringing about rotational movement.

(iv) Tensor muscles keeping the pre-patagium tensely stretched when the wing is extended during flight.

2. Endoskeleton:

In order to achieve lightness without losing strength, the bone has become pneumatic, containing air spaces in place of bone marrow.

 The skull bones are fused. Jaws lost teeth to make the skull lighter.

 The first four or five thoracic vertebrae are fused to form a firm fulcrum against which the wings can work.

 The fusion of about fourteen vertebrae of the vertebral column [thoracic-1 (last), lumbar-6, sacral-2, and caudal-5] results in the formation of a plate-like structure called synsacrum. The latter acts as a girder to support the entire weight of the body.

 The last four caudal vertebrae are fused to form a short pygostyle for providing a seat of attachment for rectrices.

 The breastbone, called the sternum, is well developed. Its posterior elongation helps in supporting the visceral organs. It bears a median ridge called a keel or carina for attachment of flight muscles. It remains firmly attached with the coracoids.

 The clavicles of the two pectoral girdles are fused ventrally to form a’ 'V'-shaped structure called the furcula, merrythought bone, or wishbone.  It acts like a spring between the two wings.

 The fusion of the distal tarsals with the metatarsals to form tarsometatarsals, as well as the fusion of proximal tarsals with the lower end of the tibia to form tibiotarsus, provides the legs with enormous strength for bipedality.

3. Digestive system:

 The efficiency of rapid digestion, for providing enormous metabolic material, is obtained by the presence of a gizzard for mastication and a crop for storage of food.

 Rectum is reduced, and the cloaca is capable of reabsorption of water from faeces and urine.

4. Respiratory system:

 In addition to lungs, birds are provided with reservoirs of air, i.e., air sacs.

 In other vertebrates, lungs are supplied with air once only during inspiration, but in birds, lungs are supplied with air twice, the second time from air sacs during expiration.

 Thus, blood in birds is oxygenated twice during a single breath. This is called double oxygenation or double ventilation.

 Thus, the respiratory system is highly adapted to supply more oxygen to the muscles.

5. Circulatory system:

 More energy is required for active flight needs a high output of the energy, which in turn requires more oxygen.

 It is made possible by an efficient circulatory system, highly adapted for carrying more oxygen.

 For this blood contains a large amount of haemoglobin, and the large heart is divided into four chambers.

6. Excretory system:

 It is modified to reduce the body weight.

 Urinary bladder is absent, and urine is in the form of semisolid uric acid.

7. Reproductive system:

 It is also specialised to reduce the unnecessary weight.

 Only the left ovary is functional.

 The number of eggs produced is also reduced.

8. Sense organs:

 The eyes are provided with an outer ring of sclerotic plates for resisting the pressure of air during flight.

 The special vascular body called the pecten contained in the eyes helps in lubrication of the eyes and in detection of minute movements at great distances.

9. Brain:

 Birds have an acute sense of sight and intelligence.

 Hence, optic lobes and cerebrum are well developed.

 The olfactory lobes are small due to poor sense of smell.

 The cerebellum is also large and convoluted to maintain the muscular coordination and equilibrium.

10. Warm-bloodedness:

 This helps in perfect aeration of blood and a great output of energy.

 The constant body temperature helps the birds to take flight at high altitudes and in all seasons.

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