Structural Organisation In Animals

The squamous epithelium cells are involved in the formation of the inner walls of blood vessels. It is a thin layer of squamous cells lined together to form a diffusion matrix in the blood vessel. Thus, due to the cellular characteristic features of Squamous epithelium, it is found in the inner walls of the blood vessels. The other options do not have the required characteristic features to form inner walls of blood vessels.

Adipose tissue is formed of adipocytes which are fat storing cells. These are, therefore found in the connective tissues beneath the skin. The other options do not have adipose tissue.

From the given options Bone, Cartilage and Blood are all specialized connective tissue whereas muscles are not categorized as connective tissue. Therefore, Muscles do not constitute as connective tissue.

Segmentation in earthworm is used for its locomotion and setae are the part of each segment which has the muscles needed for locomotion. It is present in all segments of the earthworm except in the 1^st, last and clitellar segment. Thus, the correct answer is 20^th-22^nd segment since all the other options do not have setae.

Anal styles are found in male cockroaches but they are absent in the female cockroaches. The other statements are incorrect. The number of ovarioles in each ovary is eight and not ten. Cockroaches do not have a larval stage. The cockroaches are not ureotelic but instead, they are uricotelic and has Malpighian tubules as excretory organs.

A. Adipose tissue iv. Fat storage

Explanation: Adipose tissues have cells which are known as adipocytes. These tissues are mainly responsible for the storage of energy in the form of fat.

B. Stratified epithelium iii. Skin

Explanation: Stratified epithelial cells help in the protection of the dry skin. It is multi-layered and therefore it does not have much role in secretion. Stratified epithelial cells are found mainly in the body parts which experience mechanical, chemical, osmotic or thermal stresses. Skin is an example of stratified epithelium.

C. Hyaline cartilage i. Nose

Explanation: Hyaline cartilage is a collagen abundant translucent cartilage which is found in the nose, ribs, trachea, and larynx.

D. Fluid connective tissue ii. Blood

Explanation: Blood is a fluid connective tissue as it is in the fluid form and it is involved in the binding and connection of different tissues and organs and it also helps in the transportation and exchange of various enzymes, hormones, gases, and molecules such as nitrogenous wastes, vitamins, etc.

A. Hermaphrodite ii. Testis and ovary in the same animal

Explanation: Hermaphrodites are organisms which have both the male and female reproductive organs present in the same animal. Both animals and plants exhibit this phenomenon in which they have a full or partial presence of reproductive organs of both the sexes. Examples are slugs and snails.

B. Direct development iii. Larval form absent

Explanation: Organisms which are considered to be more developed have a direct developmental stage. They do not go through the larval stage and give birth to young ones directly. There is no requirement of any transformation of organs or body parts in these organisms.

C. Chemoreceptor iv. Sense of chemical substances

Explanation: Chemo receptors are the receptor cells which help in the sensing of chemical substances. Example of a chemoreceptor is olfactory receptor neurons which are present in our nose.

D. Blood gland in earthworms i. Produces blood cells and haemoglobin

Explanation: Blood gland in the earthworm is present in the 4^th, 5^th and 6th segment of the earthworms. They are responsible for the production of blood cells and haemoglobin which is necessary for oxygen carrying.

A. Phallomere iv. The external genitalia

Explanation: Phallomere is an asymmetrical structurefound in cockroaches. It is a chitinous structure which constitutes the external genitalia in male cockroaches. It is absent in female cockroaches.

B. Gonopore iii. Opening of the ejaculatory duct

Explanation: Gonopore or gonadopore is a structure which is present in many invertebrate organisms like cockroaches. It is the opening pore of the ejaculatory duct.

C. Spermatophore ii. Bundles of sperm

Explanation: Spermatophore is a male reproductive accessory gland which is mainly found in the animal species of salamanders and arthropods. It has a mass i.e., a bundle of spermatozoa.

D. Ovarioles i. Chain of developing ova

Explanation: Ovarioles are the tubules in which ovum or ova development occurs. It is found in insects like for example cockroaches have ovarioles in which developing ova are present.

A. Touch iii. Sensory papillae

Explanation: The sensory papillae in frogs have the touch receptors in them which are used for the reciprocating the sense of touch in frogs.

B. Smell i. Nasal epithelium

Explanation:Nasal epithelium has smell receptors i.e., olfactory receptors which help in the sensing of the smell of a particular substance.

C. Cranial nerves iv. Peripheral nervous system

Explanation:The nervous system consists of two divisions: Peripheral nervous system (PNS) and Central nervous system (CNS). Cranial nerves are a part of the peripheral nervous system. Cranial nerves have further divisions for different nerves which help in sight, smell, etc.

D. Medulla oblongata ii. Foramen magnum

Explanation: Foramen magnum helps in the transmission of medulla oblongata membranes. The Foramen magnum is the passage for connecting the brain and spinal cord.

The 14^th, 15^th and 16^th number of the segment in earthworms are covered by prominent dark band or clitellum as it has a tissue known as clitellumin. It secretes albumin and mucous to form a cocoon for its eggs and it helps in the process of fertilization.

Sclerites are present in all the body segments of cockroaches. The sclerites are hard chitinous plates present in an insect. They are analogous to bones in humans.

The immature form of cockroach after hatching from the eggs is known as nymphs. At this nymphal stage, the cockroach sheds its skin which is known as moulting to reach the adult form of cockroach. A nymph requires to moult 13 times to reach the adult cockroach form.

Sound producing vocal sacs are present in Male frogs only. They are used for amplifying their mating calls to attract female frogs. They are absent in female frogs.

The process by which a tadpole develops into an adult frog is known as metamorphosis. The thyroxine hormone in tadpoles controls the process of metamorphosis. In this process the tadpole starts developing hind legs, then frontal legs and then the tail would shrinks and lungs are developed.

The earthworm’s body segmentation is known as metamerism. It is biologically very important for annelids for their locomotion. They are also known as metamers or somites. Metamerism exhibits repetition of muscle tissues.

Smooth muscle fibers can taper at both ends and does not show any striations. Smooth muscles functioning cannot be controlled directly. They are involuntary in nature. they are found in the walls of blood vessels, stomach, and intestine.

The different types of cell junctions found in the tissues are:

i)Adhering junction: They are also known as anchoring junctions as they provide the tissues with structural integrity and holds the cells together. They are found largely in the organs which go through high mechanical stress like heart and skin.

ii) Gap junction: They are also known as communicating junctions as they take part in cell signalling in the brain and they are also involved in retinal and skin cells differentiation.

iii) Tight Junction: They are also known as occluding junctions and they are responsible for acting as a barrier between the exchange of water and solutes in epithelial cells.

The two identifying features of an adult male frogs are:

i) Presence of vocal sacs: The male frogs have saggy skinned vocal sacs in their necks which amplify their sounds for attracting female frogs for mating.

ii) Presence of Copulation pad: The male frogs have a copulatory pad on the forelimbs which helps in holding the female tightly during mating.

Hypopharynx is the mouth part of cockroach which is comparable to our tongue because the hypopharynx is located medially and it is a flexible lobe which is comparable to a human tongue.

The correct arrangement of the given parts beginning from mouth is:

Mouth

Buccal cavity

Oesophagus

Stomach

Intestine

Rectum

Cloaca

Cloacal aperture.

• Cutaneous respiration refers to the exchange of gases which occurs through the from the skin while pulmonary respiration refers to the exchange of gases through the lungs.

• Cutaneous respiration is generally considered as a secondary mode of respiration while pulmonary respiration is considered to be the sole mode of respiration. Some organisms like frogs have the ability to breathe through the skin and also have lungs.

• Cutaneous respiration can be observed mainly in insects and amphibians while pulmonary respiration can be observed in mammals.

Special venous connection between the liver and intestine is known as the hepatic portal system and between kidney and intestine is known as the renal portal system. These portal systems are very essential. The blood obtained from portal veins are from these portal systems.

The hepatic caeca which are also known as gastric caeca is a 6-8 narrow and hollow ring-like blind tubules which are present in the junction of the foregut and midgut. Since cockroaches are omnivorous organisms the hepatic caeca secrete the digestive enzymes for the facilitation of digestion in cockroaches. Thus, they help in the digestion of food in cockroaches.

Frogs are very beneficial for mankind because:

• They are an important part of the food chain. They are very important predators of insects and prey of snakes, vultures, etc.

• They help the farmers by eating insects and pests for their diet and protecting the crops from insect infection.

• They are also used as a food source for humans in some regions of the world.

• They are widely used by researchers for various experimentation and testing and they are also useful in environmental indicators.

Most of the multicellular organisms possess specialized or advanced tissue level but sponges have a cellular tissue level. Their tissue organization is simple and each cell functions independently. They are loose cell aggregates although some specialized functions are carried out with division of labour among the cells. They do not form tissues and their bodies perforated which allows water to pass through them easily.

Tissue is missing in the given chain. It should be cell – tissue — organ – organ system. A tissue is a collection of similar types of cells which together forms an organ and these organs together form an organ system. Tissues carry out a function together. Similar type of cells ensemble together to form a tissue which is organized in a such a way that it forms an organ like for example stomach. When two or more organs carry out a function of a body together then they are known as an organ system. It is known as an organ system. for example, the digestive system consists of many organs working together.

Stratified epithelial cells help in the protection of the dry skin. It has multi-layers and thus does not have much role in secretion. Stratified epithelial cells are found mainly in the parts of the body which experience mechanical, chemical, osmotic or thermal stresses. It has cell layers made up of dead cells and a protein is known as keratin which is water resistant is present. These cells are often shredded due to various stresses and thus they have a limited role in secretion.

A gap junction which is also known as a communicating junction is used for facilitating intercellular communication. It occurs by the communication between two cells bypassing of small signaling molecules from one cytoplasm to adjacent cytoplasm. These small molecules are generally passed through channels formed in the cytoplasm known as connexus. These channels are opened and closed by the pH and Ca²⁺ concentration.

Blood, bone, and cartilage are called connective tissues because:

i) They are involved in the binding and connection of different tissues and organs.

ii) They help in providing structural rigidity, support and protection of the body.

iii) They are involved in the transport and exchange of various enzymes, hormones, gases and molecules such as nitrogenous wastes, vitamins, etc.

Neurons are called excitable cells because they have an electrical potential difference i.e., they are in a polarised state and they quickly stimulate to an electrical disturbance. There is a change in the potential difference and depolarisation or impulses are observed from the input to output region of the neuron which passes on to the adjacent neuron.

The special features of the membrane of the neuron are:

i) During the resting stage of the neuron, it has a sodium-potassium ion pump (i.e., Na⁺- K⁺ ion pump).

ii) If there is a change in potential difference then it is spread to the entire neuron.

iii) Stimulus in normally obtained in a place known as trigger zone in which sodium ions (i.e., Na⁺ ions) are abundantly present.

iv) Neurons are connected to several other adjacent neurons which receive and transmit impulses to various paths collectively.

Earthworm is called the friend of farmers because:

i) Earthworm helps in the aeration of the soil. It occurs when the earthworm moves through the soil and loosens it.

ii) The excreta which is released by the earthworm helps to increase the fertility of the soil.

iii) The earthworms which die or decompose and add humus to the soil which increases soil fertility.

The dorsal surface of the body of earthworm has a dark dorsal median line than the ventral surface of the body of earthworm.

There is the presence of a single median per segment by which coelomic fluid comes out in the dorsal surface of the body of earthworms whereas ventral surface has various openings like genital openings.

a. Wrong statement.

Explanation: The given statement is incorrect. In earthworms, there is presence of a pair of male genital pore.

b. Correct statement.

Explanation: The earthworm uses the setae which anchors the front of its body and helps in the locomotion of the earthworm.

c. Wrong statement.

Explanation: The muscular layer in the body wall of the earthworm is not only made up of circular muscles but it also has longitudinal muscles. These muscles are integrated together in the earthworms for its locomotion and survival.

d. Correct statement.

Explanation: Typhlosole is a dorsal flap of the intestine in a earthworm. It runs from the 25^th to 27^th segment of the earthworm’s body.

Nephridia in earthworms are useful for performing functions like excretion and osmoregulation. Although the nephridia in earthworms are similar in structure they are classified into different types based on their location. They are classified as:

1. Septal Nephridia: It is located in both sides of the intersegmental septa from the 15^th segment till the end which has about 80-100 septal nephridia on a particular segment. They open into the intestines of the earthworm.

2. Pharyngeal Nephridia: It is located in the 4^th, 5^th and 6^th segment of the earthworm. The 6^th segment nephridia open into the buccal cavity while the 4^th and 5^th nephridia segment opens into the pharynx. The excretory matter is carried into the gut by these ducts.

3. Integumentary Nephridia: It is located in the body wall i.e., the integument of the earthworm. It is present on every segment of the earthworm and it is highly abundant in the clitellar region. These nephridia discharge the excretory products directly outside the body of the earthworm.

Column AColumn B

a. TigerPanthera tigris.

b. Peacock Pavocristatus.

c. Housefly Musca domestica.

a. In cockroach grinding of food particle is performed by gizzard.

Explanation: Gizzard in the cockroaches is defined as a muscular stomach which has teeth like structures which helps in grinding the food into smaller and simpler particles.

b. Malpighian tubules help in removal of Nitrogenous excretory products.

Explanation: The Malpighian tubules are responsible for removal of nitrogenous waste in cockroaches and also in osmoregulation. The Malpighian tubules absorb the nitrogenous waste products produced by the cockroach and then covert it to simpler uric acid for excretion.

c. Hind gut of cockroach is differentiated into ileum, colon and rectum.

Explanation: Hind gut has the three differentiated parts - ileum, colon and rectum which are mainly used for the reabsorption of nutrients.

d. In cockroach blood vessels open into spaces called Haemocoel.

Explanation: The blood vessels open into spaces known as the haemocoel which are further divided into sinuses.

The special features of eyes in cockroaches are:

i) They have compound eyes i.e., it contains numerous small visual units.

ii) It has about 2000 small visual unit in an eye which is known as ommatidia.

iii) The ommatidia help the cockroach in receiving several images of a particular object. This kind of vision is known as mosaic vision.

iv) The eyes of the cockroaches have more sensitivity but lower resolution.

v) Cockroaches can see well during the night i.e., they have nocturnal vision.

Since frog is a poikilotherm i.e., it is not able to maintain constant body temperature and its temperature is dependent on the environment. So, for its survival, it goes into an isolated place or buries itself in soil and hibernates during the low-temperature seasons (i.e., winter) and it goes into aestivation during the high-temperature seasons (i.e., summer). Thus, during hibernation and aestivation, it sleeps and uses the stored energy in the body and emerges after the harsh environmental temperature has passed.

Camouflaging is very important for a frog because by the method of camouflaging it can blend itself to the surrounding place. It helps in getting protected from preys like snakes and eagles as they cannot see the camouflaged frog easily. It also helps the frog in catching its prey. Therefore, camouflage helps in the frog’s protection and catching a prey.

Column A Column B

a. Nictitating membrane i.It is the third eyelid present in frogs which protects the frog from water and land environment and also helps in lubrication of the frog’s eyes

b. Tympanum ii.It is present behind the eyes of a frog. It helps in transmitting soundwaves to the inner part of the ear in frogs.

c. Copulatory pad iii.The male frogs have a copulatory pad on the forelimbs which help in holding the female tightly during mating.

Column A Column B

a. Secretion and absorption i.Cuboidal epithelium.

Explanation:These tissues are found in organs which are involved in secretion like the salivary glands, thyroid follicles, etc. They are also found in organs specialized in diffusion like the kidney tubules.

b. Protective covering ii.Stratified epithelium.

Explanation:These tissues help in the protection of the dry skin. It has multi-layers and thus does not have much role in secretion. Stratified epithelial cells are found mainly in the parts of the body which experience mechanical, chemical, osmotic or thermal stresses.

c. Linking and supporting framework iii.Connective tissue.

Explanation:They are involved in the binding and connection of different tissues and organs and they help in providing structural rigidity, support, and protection of the body. They are also involved in the transport and exchange of various enzymes, hormones, gases and molecules such as nitrogenous wastes, vitamins, etc.

Cardiac muscle tissue is an extremely specialized tissue which is only found in the heart and it has the following special features:

i) It has similar characteristics of skeletal as well as smooth muscles. Like skeletal muscle tissue it is striated and like smooth muscle tissues it has cells connected together by intercalated discs.

ii) It can sustain contraction and relaxation rapidly and in complete efficient coordination and synchronization.

iii) The cardiac muscle tissue is involuntary and unlike other muscle tissues it doesn’t get tired.

Epithelial cells are divided into two broad categories on the basis of structural modification of the cells:

(A) Simple Epithelium and (B) Compound (Stratified) Epithelium

(A) Simple Epithelium: It is the epithelium tissue which has a single layer of cell. Thus, it is known as simple epithelium tissue. It is further divided into three types on the basis of the cell shape and structures:

i) Squamous ( flattened) cells: These are cells which flattened in shape and they allow materials and gases to pass through them by methods like diffusion and filtration. They can also secrete lubricating substances. They are found in the blood and lymphatic vessels, lining of the heart and air sacs of the lungs.

ii) Cuboidal cells: These cells are shaped like cuboid and they help in the secretion and absorption of gases and other materials in the skin. They also have microvilli present. They are found in ducts like collecting tubule of the kidney.

iii) Columnar epithelium: These cells are present in a tube or column-like shaped and they are used in absorption and secretion of certain enzymes and mucus. They can have microvilli, surface cilia, etc. They are present in the fallopian tube, small intestine, gall bladder, etc.

(B) Compound (stratified) Epithelium: It is the epithelium tissue which has two or more layers of cells lined together. It is also divided like simple epithelium on the basis of structure and it differs from simple epithelium because of the presence of more than one layer of cells.

The common features of connective tissue are:

i) They are involved in the binding and connection of different tissues and organs.

ii) They help in providing structural rigidity, support and protection of the body.

iii) They are involved in the transport and exchange of various enzymes, hormones, gases and molecules such as nitrogenous wastes, vitamins, etc.

iv) They have good regeneration ability.

v) All the connective tissues have fibers, cells and matrix present.

Difference between bones and cartilages is:

The mating process in earthworms is referred to as copulation which occurs during the rainy season. The gamete exchange in the earthworms occur through the following sequential steps:

i) Two earthworms come closer to each other and they get ventrally attached to each other in the opposite direction.

ii) The copulation process begins and the male genital pore (i.e., papilla) of one earthworm is inserted into the spermathecal pore of the other earthworm.

iii) The earthworm remains mutually close together by the penetration of setae in their bodies.

iv) Sperm and prostatic fluid of the earthworm are exchanged and the spermathecal pore stores the spermathecae.

v) The earthworms remain attached for an hour and the sperm and egg are passed into cocoon which gets secreted by the clitellar gland present in the 14^th to the 16^th segment of the earthworm.

Therefore, gamete exchange of earthworms occur through cross-fertilization and external fertilization.

Cockroaches have an advanced and well differentiated digestive system which has all the necessary primary and accessory organs. Cockroaches are omnivorous in nature. Their alimentary canal consists of three parts:

(A) Foregut

(B) Midgut

(C) Hindgut

These can be further described as:

(A) Foregut: The foregut consists of the mouth in cockroaches. The buccal cavity is located after the mouth. It consists of the tongue and hypopharynx. After the buccal cavity, the pharynx is located which is further followed by oesophagus.

The oesophagus is a narrow tube-like structure which leads to an organ known as crop.

The crop is a large sac-like structure which is used for the storage of food materials ingested by the cockroach.

(B) Midgut: Midgut is a narrow and short tube like structure. It has an organ known as gizzard which grinds the food into simpler components. The gizzard has hepatic caeca which produces digestive enzymes.

(C) Hindgut: The hindgut is further divided into three major parts: Ileum, Colon, and Rectum. The Malpighian tubules are also present in the hindgut. Malpighian tubules help in the elimination of the nitrogenous wastes and convert them to uric acid. It also maintains the ion balance in the cockroaches. The anus is the last part of the digestive system of the cockroach.

Frogs are amphibians i.e. they can live both in land as well as water. The male reproductive system of a frog consists of: a pair of testes, urogenital duct opening into the cloaca and vasa efferentia.

Through cloaca, fecal matter is excreted out and sperm is ejected.