Haemoglobin belongs to the class of conjugated protein.
1. The iron containing pigment portion haem constitutes 4%.
2. The colourless protein of the histone class is called globin.
3. Each molecule of Haemoglobin contains four atoms of iron, each of which can combine with a molecule of oxygen.

Three domain classification was proposed by Carl Woese (1977) and his co-workers. They classified organisms based on the difference in 16s rRNA genes. This adds the taxon. domain higher than the kingdom. In this system, prokaryotes are divided into two domains-bacteria and Archaea. All eukaryotes are placed under the domain Eukarya. Archie appears to have common features with Eukarya. Archaea differ from bacteria in cell wall composition and differ from bacteria and eukaryotes in membrane composition and rRNA types.

Cephalochordates are marine forms, found in shallow waters, leading a burrowing mode of life. They are small fish like coelomate forms with chordate characters such us notochord, dorsal tubular nerve cord and pharyngeal gill slits throughout their life. Closed type of circulatory system is seen without heart. Excretion is by protonephridia. Sexes are separate, Fertilization is external. eg. Branchiostoma.

(i) Limulus (King crab, a living fossil)
(ii) Palamnaeus (Scorpion)
(iii) Eupagarus (Hermit crab)
(iv) Apis (Honey bee)
(v) Musca (House fly)
(vi) Vectors - Anopheles, Culex, Aedes (mosquitoes)
(vii) Economically important insects - Apis- (Honey bee), Bombyx (Silk worm)
(viii) Laccifer (Lac insects)
(ix) Living fossils Limulus-(King crab)

The earthworm's receptors are stimulated by a group of slender columnar cells connected with nerves. The Photoreceptors (sense of light) are found on the dorsal surface of the body" Gustatory (sense of taste) and olfactory receptors (sense of smell) are found in the buccal "cavity. Tactile receptors (sense of touch), chemoreceptors (detect chemical changes) and thermoreceptors (changes in temperature) are present in the prostomium and the body wall.

The large intestine consists of caecum, colon and rectum. The caecum is a small blind pouch-like structure that opens into the colon and it possesses a narrow finger-like tubular projection called vermiform appendix. Both caecum and vermiform appendix are large in herbivorous animal and act as an important site for cellulose digestion with the help of symbiotic bacteria. The colon is divided into four regions - an ascending, a transverse, a descending part and a sigmoid colon. The colon is lined by dilations called haustra (singular - haustrum). The "S" shaped sigmoid colon (pelvic colon) opens into the rectum. Rectum is concerned with temporary storage of faeces. The rectum open out through the anus. The anus is guarded by two anal sphincter muscles. The anal mucosa is folded into several vertical folds and contains arteries and veins called anal columns. Anal column may get enlarged. and causes piles or haemorrhoids.

1. Swollen neck is due to Simple goitre, a disease caused by hyposecretion of thyroxine by thyroid gland.
2. It is due to deficiency of iodine which is obtained from salt.
3. In coastal areas the salt content of the soil is good and all fruits, vegetables etc are rich in salts.
4. In hilly areas, the soil has very little salt content so people do not get enough iodine through their diet.
5. Treatment is done by medication.

Brain stem
A- Thalamus
B- Pineal gland
C- Corpora quadrigemina
D- Pons
E- Cerebral peduncle
F- Medulla oblongata

1. Destroys aging and defective blood cells.
2. Stores glucose in the form of glycogen or disperses glucose into the bloodstream with the help of pancreatic hormones.
3. Stores fat soluble vitamins and iron.
4. Detoxifies toxic substances.

If the cardiac sphincter does not contract properly during the churning action of the stomach the gastric juice with acid may flow back into the oesophagus and cause heart burn, resulting in GERD (Gastro Oesophagus Reflex Disorder).

Stroke volume SV = EDV - ESV
EDV - Amount of blood getting collected in ventricle during diastole.
ESV - Volume of blood remaining in ventricle after contraction.
1. Heart's pumping action maintains balance between cardiac output and venous return, Heart is a double pump.
2. Each side of the heart can fail independently of the other.
3. Increase in EDV can increase SV, On the other hand decrease in venous return and EDV can decrease Sv.
4. Similarly changes ·of EDV and ESV on SV are not independent.

1. The Photoreceptors (sense of light) are found on the dorsal surface of the body.
2. Gustatory (sense of taste) and olfactory receptors (sense of smell) are found in the buccal cavity.
3. Tactile receptors (sense of touch), chemoreceptors (detect chemical changes) and thermoreceptors (changes in temperature) are present in the prostomium and the body wall.
4. Hence they can sense activity in their habitat easily without eyes, ears or a nose.

Direct Development:
Advantages:
1. The young ones resemble the adult directly and no larval stages occur.
2. The eggs of these animals have lot of yolk for the young ones to grow or are fed by the mother's tissues. (human being) in the larval stages.
3. Parental care is seen in many cases.
Disadvantages:
1. Since the parents and young ones are found in the same habitat. they have to share the same resources.
2. In case of calamities/disasters, they will perish together.
Indirect Development: Advantages:
1. The larval forms are much different from the adult and thrive on different food resources
2. They also grow in a different ecological habitat. Hence in case of calamities, they may continue to exist even if the adults Perish.
3. Indirect development is a better means for the species to survive.
Disadvantages:
1. Chances of all larvae developing into adult cannot be assumed.
2. Eggs have very little yolk.
3. Parental care is not seen.

Differentiation of a definite head at the anterior end is called cephalization. The nervous tissue is concentrated is the head (brain) with formation of sense organs.
1. Since the head forms the anterior part of the body, cephalization helps the animal to sense I the surrounding with the help of sense organs.
2. They can detect source of food and also protect themselves from enemies.
3. Formation of head also leads to formation of apperdages such as antennae which will be of use in finding food.

1. Thermus aquatics is a bacterium which can tolerate high Temperatures.
2. The first DNA polymerase enzyme was isolated from T. aquaticus. It is used in PCR (Polymerase Chain Reaction) for DNA amplification.

Prokaryotes which have the ability to grow in extreme conditions like volcano vents, hot springs and polar ice caps are called extremophiles. They have adaptations such as :
1. Capacity to synthesize their food without sunlight and oxygen by utilizing hydrogen sulphide and other chemicals from the volcanic vents.
2. Some of them produce methane (Methanogens).
3. Some live in salty environments (Halophiles).
4. Some are thermoacidophiles which thrive in acidic environments and at high temperature.

1. In a cladogram, a shared character is one that two lineages have in common
2. Derived character is one that evolved in the lineage leading up to a clade.

(i) The appendages form mouth parts, which are of biting and chewing type. This is called mandibulate or orthopterus type.
(ii) So cockroach belong to mandibulata
(iii) This type of mouth part is called as the fundamental type as in human beings.