Process of Asexual Reproduction in Bacteria   i) Bacteria reproduce asexually through binary fission.   ii) Binary fission takes place about every 20 minutes.   iii) Bacteria have a single circular chromosome made of DNA.   iv) When DNA molecule replicates, it results in the formation of two chromosomes.   v) These two chromosomes move…

Hereditary and Non Hereditary Characteristics   Hereditary Characters:   Those characteristics, which are transmitted, form parents to offspring. For example eye colour, hair colour etc.   Non-hereditary Characters:   Those characteristics, which are not, transferred form parents to offspring. For example parent’s habits or any body part lost or weakened due to any disease.  …

What is Evolution   The diverse forms of life that are now in existence have come into being through a gradual and continual process of modification of ancestral forms. This modification is called evolution.   Often we create a project of a literary hero and transfer it into our life. We think, worry, make a…

Short Note on Fertilization of Frog   Structure of Eggs:   i) Eggs are produced in ovaries present in abdomen.   ii) Each egg is like a small ball spherical structure having a. One half pigmented part called animal hemisphere.   One yellowish part due to storage of food or yolk called vegetal hemisphere.  …

Methods of Sexual Reproduction in Animals   The sexual reproduction involves the fusion of two haploid cells (gametes) to form a diploid zygote.   Role of Meiosis:   i) Meiosis help to reduce the number of chromosomes to one half in gametes.   ii) It also helps in exchange of genetic material by the process…

Methods of Asexual Reproduction in Animals Binary Fission:   i) It takes place in unicellular organisms.   ii) In this method one cell gets divided into two daughter cells under suitable conditions.   iii) Daughter cells are identical to parent cell.   iv) In this method nucleus becomes elongated and divides into two.   v)…

Embryo Embryology and Foetus   Embryo:   The developing individual in its early stages is called an embryo.   Foetus:   In placental mammals at the later stage of development embryo is called a foetus.   Embryology:   The study of embryo is called embryology.     “Python” – general knowledge to get a good…

Necessary Conditions for Seeds to Germinate   Seeds need sufficient food for germination, which they get from cotyledons. Following environmental conditions are necessary for seed germination:   Moisture or Water:   i) Seed absorb water and swell up, which cause seed coat to burst. This help the root to emerge out.   ii) Water also…

Structure of a Seed   A seed consists of two parts:   Seed Coat:   i) Testa is the outer layer of seed coat, which protects the embryo.   ii) Tegmen is the inner layer of testa. It also help in protection.   iii) A scar on seed coat is called hilum, which tell us…

Agents of Seed and Fruits Dispersal   Dispersal by Wind:   The seeds, which are of smaller size and lighter, are carried away by wind. These may have wings or hairs, which help them to be dispersed by wind. Examples are cotton seed, sumbal seed etc.   Dispersal by Animals:   Animals help dispersal of…