Anas Zoology

  What is Amensalism ? Amensalism is association between two species, in which one species is harmed and other species is unaffected.  Examples: The mould penicillium creates a substance known a penicillin, this is extremely toxic to bacteria. The mould is unaffected but the bacteria dies. The black walnut secretes a chemical from its roots known as juglone, this harms the neighbouring plants, the black walnut is unaffected.

  What is Neutralism? Neutralism is a type of symbiotic relationship in which two different species are not affected by association with one another. (Both the populations do not affect each other) The term Neutralism was introduce by Eugene Odum an American biologist Examples: 1) Grass Carp and Catla residing on the surface of a pond do not affect one another as their food habits are different. Grass Carp feeds on macro vegetation while Catla feeds on zooplanktons. Grass Carp Catla                        

Mineral : Mineral is any substance which is required by plants for physiological functioning and it is mostly taken from the soil. What are Essential Elements ? Any element that is important for a physiological role in plant and the absence of this element prevents the plant from completing its life cycle is an essential element. According to Arnon and Stout three criteria must be met for an element to be considered essential, these are: A plant must be unable to complete its life cycle in the absence of the essential element. The function of the essential element cannot be replaced by another element i.e. deficiency of any one element cannot be met by supplying other element. The essential element must be directly involved in plant metabolism. Essential elements are divided into two categories : Macroelements and Microelements Macroelements: The mineral/element is required in large quantity, conc > 1ppm. Also known as major elements. Macroelements consists of Phosphorous (P), Potas

Skeleton includes bones and cartilages. Definition of Bone Bone is a living tissue that makes up the skeleton of the body. Composition of Bone: Bone is composed of inorganic calcium salts. It consist mainly of calcium phosphate and partly of calcium carbonate. The inorganic calcium salt is calcium hydroxy-apatite [Ca 10 (PO 4 ) 6 (OH) 2 ] It also consist of the organic connective tissue made up of collagen fibres. Functions of Bones: It gives shape and support to the body. Bones contain bone marrow. Bone marrow contains the reticuloendothelial cells, these cells are phagocytic in nature and take part in immune responses of the body. Bone marrow also helps to manufacture the blood cells. Bones provides the surface for the attachment of muscles, tendons and ligaments. They store about 97% of the body's calcium and phosphorous. They protect the vital organs of body e.g. Skull protects the brain, vertebral column protects the spinal cord. 

 Animals are metazoans that differ from plant in number of characteristics like absence of plastids, cell wall and central vacuole. There are around 1.2 million known species of animals, but scientists estimate there are closer to 8.7 million species on earth. they show great diversity in shape, size, colour, habits, habitat, structures etc. CHARACTERISTICS OF ANIMALIA: They are multicellular consumers of the ecosystem. They are made up of eukaryotic cells and have no cell wall, plastids, central vacuole and photosynthetic pigments. Lower animals exhibit cellular or tissue level of organization and higher animals have organ system level of organization. Mostly free living and some are fixed (sponges and several coelenterates). They take food by ingestion i.e. holozoic in nutrition and digestion takes place in an internal cavity. Some forms have absorptive nutrition and their digestive cavity is absent. The undigested food is removed by egestion.  They have muscle cells (for contraction

PROKARYOTES: Cell is small in size (0.1 to 5 μm) Cell wall is made of non cellulosic material. They generally contain muramic acid (amino acid derivative-peptidoglycan). Mucopolysaccharide capsule is present in many cells. Cell membranes infolds to form mesosomes that controls cellular respiration and cell division. An organized nucleus is absent. Here chromatin network is in direct contact with cytoplasm. It is called nucleoid / genophore. Mostly prokaryotes have multiple nucleoids. DNA is circular and naked. Usually polycistronic DNA is present. Only one kind of RNA polymerase is present. Both transcription and translocation occurs in the cytoplasm. Generally extranuclear chromosomes are present either in the form of plasmid or episome. Ribosome is 70S (50S + 30S) Protein synthesis is inhibited by chloramphenicol. Cytoplasm lacks membrane bound organelles. Flagella if present is mad up of single stranded protein, flagellin. Microfilaments - Actin and Myosin are absent. Sap vacuoles a

 The skin and their associated structure make up the integumentary system. Skin protects terrestrial organisms from desiccation and from heat loss. The largest organ of mammal is skin. It protects the body against physical,chemical, and biological attacks, it helps to regulate body temperature, it is used to communicate to other individuals, and a skin derivative provides nourishment for the young. Mammal skin is composed of two layers, the dermis and the epidermis. Below the dermis there is a layer known as hypodermis, some may consider this as the third layer of skin. HISTOLOGY OF SKIN : Skin has four layers of cells is referred to as thin skin. From deep to superficial, these layers are the stratum basale, stratum spinosum, stratum granulosum and stratum corneum. Most part of the skin can be classified as thin skin. Thick skin is found only on the palms of the hands and the soles of the feet. It has a fifth layer, called the stratum lucidum, which is located between the stratum corn