The Knowledge

Types of wetlands There are five recognized types of wetlands.(See Wetland ) 1.Marine These are coastal wetlands including coastal lagoons,rocky shores,and coral reefs. Marine wetland 2.Estuarine It include deltas,tidal marshes,and mangrove swamps. Estuarine wetland   3.Lacustrine These wetlands are associated with lakes. Lacustrine wetland   4.Riverine These wetlands are found along rivers and streams. Riverine wetland   5.Palustrine These wetlands lack following water,”marshy”,marshes,swamps and bogs. Palustrine wetland   (See  Impoetance of wetland )  

 Importance of wetlands. Wetland (See Wetland ) are among the world's most productive environments. Wetlands provide: Source of recreation and tourism opportunities •Hiking •Fishing •Bird watching •Photography •Hunting Flood protection •Wetland acts as natural buffers,soaking up and storing a significant amount of floodwater. •A wetland can typically store about three-acre feet of water,or one million gallons. •Wetlands are cradles of biological diversity •They support high concentrations of •Invertebrate species •Fish •Amphibians •Birds •Reptiles •Mammals •Wetlands are also important storehouses of plant genetic material. Source of food •Rice is a common wetland plant. •Fisheries,over two thirds of world's fish harvest is linked to the health of wetland areas. Other benefits They are source of •Timber and other building materials •Energy resources •Wildlife resources Source of herbal medicines Wetland provide a wide r

Fertilization is a process of sexual reproduction in which fusion of haploid gamets,egg(from female) and sperm from male occurs and a diploid cell is formed called zygote .In human,fertilization occurs in the ampulla region of fallopian tube.I n some species fertilization occurs outside the body mostly found in aquatic animals.   Steps of egg fertilization:                                         Contact and recognition between sperm and egg      ↓        Regulation of sperm entry into egg  ↓   Only one sperm fertilizes the egg   ↓   Fusion of genetic material of sperm and egg     ↓   Activation of egg metabolism to start development Figure showing one sperm fusing with the egg In human,a healthy male produces 15 million to 200 million of sperms per milliliter.But only one sperm can fertilize the egg.After egg is fertilized,it becomes zygote and zygote moves through the fallopian tube and enters the uterus/womb where it implants to the uterine walls and after p

 Developmental biology is a science and branch of biology that deals with the  development process of multicellular organisms.In this field,it is studied that how multicellular organisms pass through the development stages.In development,organisms change their shape,size and characteristics and develop new organs that is totally controlled by genes.

POLYSPERM Polyspermy refers to the egg that has been fertilized by more than one sperm. Types of polyspermy There are two types of polyspermy. 1.Fast block to polyspermy 2.Slow block to polyspermy Fast block to Polyspermy The Fast block polyspermy is achieved by changing the electric potential of the egg plasma membrane. This membrane provides a selective barrier between the egg cytoplasm and the outside environment, and the ionic concentration of the egg differs greatly from that of its surroundings. This concentration difference is especially significant for sodium and potassium ions. Seawater has a particularly high sodium ion concentration, whereas the egg cytoplasm contains relatively little sodium. The reverse is the case with potassium ions. Slow block to polyspermy The eggs of sea urchins (and many other animals) have a second mechanism to ensure that multiple sperm do not enter the egg cytoplasm. The fast block to polyspermy is transient , since the membrane pot

Wetland   What are wetlands?   Wetlands are the areas where water is primary factor that control the environment and associated plant and animal life. Figure:Wetland Ramsar Wetlands are defined according to Ramsar convention as “Areas of marsh,fen,peat land or water,whether natural or artificial,permanent or temporary,with water that is static or salt,including areas of marine the depth of which at low tide does not exceed six meters”. ( See Imortance of wetland ) (See  Types of wetland )

Biological filtration   In biological filtration a tank is used and bacteria breakdown the dangerous ammonia into nitrites and then nitrite is further broken down into less toxic nitrates. Nitrogen is an essential nutrient to all living organisms and is found in proteins,nucleic acids,adenosine phosphates,pyridine nucleotides and pigments                                                                                           In aquaculture there are 4 primary sources of nitrogenous wastes: 1:Urea,uric acid and amino acids excreted by fish 2:Organic debris from dead and dying organisms 3:Uneaten feed and feces and 4:Nitrogenous gas from atmosphere • NH 3, NO 2 and NO 3 are highly soluble in water. • NH 3 is converted to NO 3 by oxidation process and overall process is called nitrification or nitrogen cycle and its reversal is called denitrification.     NH 3       → NO 2 - →     NO 3 -               It requires 3 moles of oxygen to convert one mole of ammonia t