biology notes class

REPRODUCTION   IN   LICHENS - Commonly lichens produced by vegetative , asexual and sexual methords of reproduction. A. VEGETATIVE REPRODUCTION a) BY FRAGMENTION - Death and decay of older parts of the thalus produce smaller pieces. - This pieces give rise to new thalus. - In sometime the broken poritin are born in other substrated by wind. - Each flagelats contains algal and fungal or getting a suitable substrated , each portion give rise to a new thallus.   b) BY SOREDIA - It is the most common methord of vegetative reproduction. - Soredia are dispersed by wind sometime they form a massive cating on the thallus called as soredia dust. - Each soredium contain fungal hyphae and algal cell , on getting suitable substratun give rise to new lichen thallus.   c) BY ISIDIA - Isidia are broken off from the parent thallus and dispresed to other substrate. - Each isidium contain fungal and algal componets, so they get suitable...

EXCRETION    IN ANNILIDA - Excretion is defined as the separetion elimation of nitrogenus west from body to out side. - The organ involve in excretion called as ecretory organ. - In annelida exretion is brought about by these following organ. NEPHRIDIA - These are coild tubules arrenged segmentally drive from ectoderm and projected in the nephridia named as 1. proto-nephridia 2. meta-nrphridia A. PROTONEPHRIDIA - These are primitive type of nephridia open to exterior by an opening called nephridiapore. - Internaly it   blindly open towords coelom and are branched. - Each branch ends in a tubular cell ,   called solencytes. - It is a cavity surrounded by cytoplasm mass. - Flagellum arises from the mass of cytoplasm. - It is found in alcepa. B. METANEPHRIDIA - It has two opening ,one end is open to the coelom by funnel like structure called nephrostome. - And orther end open to anterior by nephridiapore,found in nereis. - Nep...

Larval     Form     Of     Echinoderm - The development of echinoderm may be direct or indirect. - The direct development there is no larval form but in indirect development there are larval forms. - Larval form are different parents. 1. DIPLEURUAL    LARVA -   It is a foundamental larva of all echinoderm. -   It is a microscoping and free swiming larva. -   Body is egg-shaped / oval and bilateralaly symmetrical. -   dipleurla 2 cillia bands named as a. Perioral band: used for locomotion. b. Adoral band: used for collecting of food. -   Dipleurual larva developes in next larva named as Bipinaria larva. 2. BIPINARIA    LARVA -   It is a 2 nd   larva stage of star fish / asteroidea. -   It is a minute and microscopic and free swinminh larva. - The body is bilateral symmetrical. -   It has straight elimentary canal , mouth to anus. -   Body has...

↞RESPIRATION    IN    MOLLUSCA - Mollusce is a large phylum of invertebrate animal. - Mollusca are the largest marine phylum about 23% of all merine organism .               The respiration bring about the utilization of O 2 whitin the body                  and given out of CO 2 outside. - Respiretory organ in mullusca, these are, CTENIDIA - Ctenidia are the organs of aquatic respiratory and   it is present in aquatic mollusca. - The pulmonary chamber is the organ of aerial respiration and is present in terrestrial mollusca. - But in certain cases in pila , planorbis etc, both methords of respiration are used . - It is simplest methord in mollusca. - Ctenidia respiration through skin.   STRUCTURE   OF   CTENIDIA - The ctenidium has a cintrol axis one or two rows of f...

PEARL FORMATION                        Their are 3 types of pearl formation named as,               1. Natural              2. Cultured             3. Imitation - Pearl is a hard glistening object produced within the shoft tissue of a living molluca. - Pearl are found in different type of colour like that pink ,white, black ,gree, pink etc. PEARL FORMATION - The foreign object enters the body of a bivalve ( one type of mollusca) in between the shell and mantle. - The mantle immediately gets irritated and encloses it like a sac. - The mantle wall then starts secreting layers and around the foreign object. - The mantle wall secretes continuously several layer around the foreign object, and finally pearl is formed. - The foreign object like that...

VISION  IN ARTHROPODS Arthropods eyes are simple as well as compound eyes. -that means insects are both types of eyes are considered to be most succssful animal an earth. A. THE COMPUNUD EYES -A pair of compound eyes for vision that seen in crabs, shrips, barnacles, water fleas etc. -In compound eyes , 2 eyes is composed of a large number of independent visual unit called ommatida -Ommatidia are connected to the optic nervs. -Ommatidia are 2 types, a.     Dioptrical region : Receiving and focusing light rays. b.     Inner sensory region : Receiving light and sending the nerve impulse to the brain. -   Sensory region analyses the impulse as image of the object. - Compound eye is incapable of giving distance vision but it capable to 360 0 view. - It is a large globular and a movable stalk. - Each ommatidium is capable of producing image of a small part of the object seen and not the entair object. - All...