生物4（Biology 4）.doc

生物4（Biology 4） Seventh unit life extension and development in biosphere Chapter 1 biological reproduction and development I. reproduction of plants 1. sexual reproduction (see page fourth of this material) 2. asexual reproduction 1). A plant cutting branches, the branches of the lower part is inserted into the moist soil, soon at optimum temperature, lower branches grow adventitious roots, shoot germination, finally grown into a new individual. Geranium, grape, rose 2) grafting: the bud or branch of a plant is attached to another plant, so that the two parts that combine together grow into a whole plant body. Scion budding Rootstock grafting The key is to ensure that the cambium of the scion is closely integrated with the cambium of the rootstock. 3) tissue culture: (1) totipotent of plant cells: the ability of any living cell of a plant to differentiate and develop into a complete plant at appropriate conditions. (2) the process of tissue culture: Artificially configured nutrients differentiate between roots and shoots by transplanting Plant tissue, callus, Plantlet in vitro, plant (3) the advantage of tissue culture is that it can propagate in a short time and breed fast; it can breed virus-free plants; it is not affected by seasons; it is easy to induce variation and is beneficial to scientific research and production. Two. Reproduction and development of insects 1. reproduction and development of Bombyx mori The life cycle of Bombyx mori: eggs, larvae, pupae, adults Metamorphosis: the development of fertilized eggs into new individuals, the larvae of silkworm and adult form, structure and life habits vary greatly 2. development of other insects 1) complete metamorphosis: four stages of life, including eggs, larvae, pupae, and adults. Such as bees, flies, mosquitoes, Pieris rapae. 2) incomplete metamorphosis: three stages of life through eggs, nymphs, and adults. For example: the locusts, crickets, cricket, mantis. Three. Reproduction and development of Amphibian