SCIENCE - REPRODUCTIVE & others

• There are two types of reproduction: asexual reproduction and sexual reproduction.
• Asexual reproduction involves the creation of offspring from one parent without the involvement of gametes.
• Sexual reproduction involves the creation of offspring from two parents, with the male and female gametes involved.
• The male reproductive organ is the testes, and their reproductive cells are the sperms.
• The female reproductive organs are the ovaries, and their reproductive cells are the eggs which are otherwise called as ova(plural) or ovum (singular).
• The human sperm is produced by the testes, and millions of sperms are produced by the testes.
• Each sperm is a single cell with all the usual cell components.
• The male reproductive system consists of the testes, epididymis, vas deferens, and seminal vesicles.
• The female reproductive system consists of the ovaries, uterus, Fallopian tubes, and vagina.
• A zygote is a single cell formed when a male gamete (sperm) fuses with the female gamete (egg) during fertilization.
• An embryo is a ball of cells that develops into different tissues and organs of the body during the process of post fertilization.
• Fertilization is the process of the fusion of the male gamete with the female gamete.
• Internal fertilization takes place when the fusion of the male and female gamete takes place inside the body of the female, as in mammals, birds, insects, reptiles.
• External fertilization takes place when the fusion of the male and female reproductive cells or gametes takes place outside the body of female, as in frogs, fish, starfish.
• Oviparous animals lay eggs, such as birds, insects, and frogs.
• Viviparous animals give birth to young ones, such as humans and mammals.
• The process of fertilization in human beings involves sexual reproduction, with the male reproductive organ producing sperms and the female reproductive organ producing ova.
• The fusion of the sperm and the ovum takes place inside the body of the female to form zygote (internal fertilization).
• The single celled zygote begins to develop into an embryo which attaches itself to the female uterus wall.
• In budding, a part of the organism starts bulging out and slowly it grows and develops into a separate individual.
• Binary fission is a type of asexual reproduction in which a single cell divides into two halves.
• The development of chick from the embryo takes place outside the body.
• Metamorphosis is the complete change or form of an organism as it develops from a young one to an adult.
• The fertilized egg or the zygote is transferred to the uterus where it grows and develops.
• Asexual reproduction is a mode of reproduction in which only one parent is involved to reproduce the offspring.
• The hard shell that you see in a hen’s egg is one such protective layer.
• Examples of organisms that undergo binary fission are bacteria, amoeba, paramecium.
• Asexual reproduction is generally observed in very small sized organisms.
• The embryo travels down many protective layers as it develops into a chick.
• When the hen sits on the eggs for about three weeks to provide sufficient warmth, the embryo develops into a chick.
• After the hard shell is formed around the developing embryo, the hen finally lays the egg.
• Fishes and frogs produce enormous number of gametes because there are other animals in the pond which may feed on the eggs.
• In asexual reproduction, the offspring produced are exact copies of their parents.
• Examples of organisms that undergo budding are Hydra.
• Invitro fertilization is a process where the sperm and the egg are taken out and allowed to fertilize outside the body.
• Binary fission, budding, fragmentation are some methods of asexual reproduction.
• The release of a mature egg from the ovaries is called ovulation.
• The life cycle of a butterfly includes egg, larva, pupa, adult.
• The life cycle of a frog includes eggs, tadpoles, growth of gills, hind legs growth, fore legs growth, shrinking tail, adult frog.
• Fishes and frogs fertilize externally producing enormous number of gametes because all the eggs may not get fertilized and develop into new individuals and some eggs may be lost due to environment agents like flowing water, wind, rainfall etc.