Animal Kingdom Test - 8

In Hydra, musculo-nutritive cells are present which is large, columnar, nucleated and vacuolated. The free ends of the cells project into coelenteron which bear pseudopodia and one to five flagella. With the help of pseudopodia and flagella, the cells engulf food material (holozoic ingestion).

Asexual reproduction produces individuals that are genetically identical to the parent plant. Roots such as corms, stem tubers, rhizomes, and stolon undergo vegetative reproduction. Some plants can produce seeds without fertilization via apomixis where the ovule or ovary gives rise to new seeds.

Zoochlorella is a green algae which live in nutritive cells of gastrovascular cavity of Hydra.this green. algae show SYMBIOSIS with hydra.Due to this algae hydra looks green.

Most hydras are dioecious but some species are monoecious (hermaphrodite) in which sperms mature before the eggs, and self-fertilization is prevented. 2. Sexual reproduction usually occurs in winter and spring months.

The first neurons were probably connected in a diffuse network across the body of a creature like this hydra. This kind of structure, known as a nerve net, can still be seen in the quivering bodies of jellyfish and sea anemones.

Diploblasty is a condition of the blastula in which there are two primary germ layers: the ectoderm and endodermHydra are carnivorous and feed mainly on small crustaceans like water fleas (Daphnia) and small worms. Although hydra are fairly simple animals, the stinging cells which they use to catch their prey are quite complex structures.

Hydra is known for high power of regeneration. That means, when it is cut into small segments, it can  give rise to the complete organism.

Crustaceans may pass through a number of larval and immature stages between hatching from their eggs and reaching their adult form. Each of the stages is separated by a moult, in which the hard exoskeleton is shed to allow the animal to grow.

Hydra (phylum: Cnidaria) body wall consists of outer epidermis and inner gastrodermis separated by acellular mesoglea. Epitheliomuscular cells are present in the epidermis and serve in protection and shortening of body and tentacles by contraction. A diffuse network of nerve cells in epidermis makes nerve net that serves to conduct impulses in all directions and helps Hydra (cnidarians) to respond. Cnidocyte is the stinging cells present in the epidermis of Hydra and serve in protection and catching the prey. Choanocytes, the flagellated collar cells are the characteristic feature of phylum Porifera and serve in setting the water current that delivers food and oxygen and removes waste and carbon dioxide.
So, the correct answer is option D.

Hydra is primite so as it have diffuse nervous system and diffuse nervous system is a primitive system. In diffuse systems nerve cells are distributed throughout the organism, usually beneath the outer epidermal layer that is why it's impulse transmission is in all directions.

When a hydra is well fed in abundance of CO₂, a new bud can form every two days. In harsh conditions Sexual reproduction occurs in some Hydra. Swellings in the body wall develop into either ovaries or testes. The testes release free-swimming gametes into the water, and these can fertilize the egg in the ovary of another individual.

When not so attached it is helpless, for it has not the power of swimming. When attached the body is usually moderately expanded, seldom extremely so. In Hydra viridis the tentacles, also moderately expanded, extend obliquely outward and forward, forming the framework of a sort of funnel with the hypostome at the bottom. If dettaches causing the hydra to float upside- down as the base detaches, no food catchment, etc

The chemostimulants can be divided into 3 classes on the basis of specificities of the responses they elicit. The first class includes tripeptides glutathione (reduced form) and S-methyl-glutathione. These chemicals evoke all three types of responses. The second class contains dipeptidesγ-glutamylcysteine,γ-glutamyl-S-methyl-cysteine andγ-glutamyl-α-amino butyrate and amino acidl-arginine. These chemicals evoke mouth-opening and writhing of tentacles, but not ball-formation. The third group contains amino acidsl-leucine,l-tryptophan andl-lysine. These chemicals evoke writhing and ball-formation of tentacles but not moutho-pening. These observations indicate the existence of different specificities of the three feeding responses inHydra to chemostimulants.

Cnidarian animals are characterised with cnidoblasts or cnidocytes (which contain the stinging capsules or nematocysts) present on the tentacles and the body. Cnidoblasts are used for anchorage, defense and for the capture of prey. Nematoblasts of cnidoblasts are sensory in nature and they contain nematocyst apparatus.
Therefore, the correct answer is option C.

The gastrovascular cavity is the primary organ of digestion and circulation in two major animal phyla: the Cnidaria (including jellyfish and corals) and Platyhelminthes (flatworms). ... This cavity has only one opening to the outside which, in most cnidarians, is surrounded by tentacles for capturing prey.

Hypnotoxin a neurotoxin found in the tentacles of the Portuguese man-of-war that depresses activity of the central nervous system.Nematocyst. Nematocyst, minute, elongated, or spherical capsule produced exclusively by members of the phylum Cnidaria (e.g., jellyfish, corals, sea anemones). Several such capsules occur on the body surface. The threads of some nematocysts ensnare small prey by wrapping about them.

Hydra can digest proteins, fats, and some carbohydrates, but it does not digest starch because they lack salivary amylase and pancreatic amylase.
So, the correct answer is 'Starch'.

Hydra belongs to cnidarians which are radially symmetrical and diploblastic acoelomate.

Habitat: Hydra can be found in large variety of freshwater habitats. They mostly occur in ponds, lakes, and slow flowing parts of streams and rivers. Hydra are sessile and live attached to aquatic vegetation, submerged wood, or stones.

In cnidarians, the cell can use its thread and nematocyst only once. Later the used cell is replaced by newly generated cnidoblast cell.

Blind sac is a characteristic of Hydra. The body has a cavity or is like a sac with only one opening. The digestive tract is, therefore, incomplete in this type of body plan. They have diploblastic body plan with two germ layer which is known as ectoderm and endoderm.
Therefore, the correct answer is option B.

In Hydra, undigested residues are egested from coelenteron through the mouth, while nitrogenous excretory product (ammonia) is removed from the general body surface. They lack any organ level organisation, they have a tissue level organisation. They have a gastrovascular cavity which helps in digestion and absorption. 

So, the correct answer is option C.

Hydra which belongs to the phylum coelenterata has nerve cells but no brain. Its nervous system consists of nerve cells and their processes. Sensory cells are also present. Sponges do not have nerve cells, they lack nervous system. Earthworm (annelida) has nervous system consisting of a circumenteric nerve ring and a solid, double, midventral nerve cord with ganglia. Cockroach (arthropoda) has the nervous system as that of earthworm.
So, the correct answer is 'Hydra'.

Because hydra reproduces vegetatively through a process called budding. In budding, each bud grows into a new individual and hence, all the cut three parts grows into a new individual.

Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation and parasitoidism.Hydra are inconspicuous freshwater relatives of corals, sea anemones and jellyfish. All are members of the phylum Cnidaria, characterized by radially symmetrical bodies, presence of stinging tentacles and a simple gut with only one opening (gastrovascular cavity).

Buds are produced every two to three days under favourable conditions. Buds later break free, but are genetically identical to the parents (clones). Under favorable conditions, hydra may possess several buds at various stages of development. Hydras often have four buds at a time.