Tiêu đề 01. REPRODUCTION IN ORGANISMS.pdf ✅

VEGETATIVE PROPAGATION Vegative propagules are able to give rise to new plants. Only in Plants Narrow, green and horizontal branches develop from the base of root. Underground stems that store food Eg:- Ginger. Slender underground branches develop from base of aerial shoot. Eg:- Mint Underground stem or root having adventitious buds. Eg. Potato one internode long runner occurs in some aquatic plants. Eg. Pistia RUNNER RHIZOME SUCKER OFFSET TUBER FERTILIZATION • Marked by the fusion of male & female gametes, also called syngamy • Can be of two types • In terrestrial animals birds & higher plants. • Egg inside the female body fuses with male gamete. • In aquatic animals & amphibians • Number of gametes released are more • High risk of predation. INTERNAL EXTERNAL in Amoeba & Paramecium in Plasmodium in Yeast & Hydra Motile in Chlamydomonas, Non – motile in penicillium in Planeria, Flatworms Leaf buds of Bryophyllum Single cell divide into two daughter cells Single cell divide into multiple daughter cells By unequal division bud is formed which forms new offspring Motile (zoospores) & non – motile (conidia) spores are formed in Monera, protist, algae and fungi. Growth of fragmented region into new organism New plants are formed from vegetative propagules like buds, tuber etc. Binary Multiple Budding Fragmentation Vegetative Propagation SporeFormation Gemmule formation in sponges (Budding) Unfertilized egg develops into an adult Eg; Honey bees Clone is morphologically & genetically similar organism (identical) formed by asexual reproduction Single parent is involved Parthenogenesi Gamete Transfer Male and female gametes formation Male gamete – antherozoid or sperm Female gamete– egg or ovum Gametogenesis PRE - FERTILIZATION EVENTS SEXUAL Male Gamete Fusion Zygote New Organism Female Gamete + Male gamete is mainly motile and female is stationary Two parents of opposite sexes are involved • In reptiles & birds fertilized eggs are laid with hard calcareous shell. • Young ones hatch after incubation • In majority of mammals zygote develops into young one inside the body of female. • Young ones are delivered after birth. OVIPAROUS VIVIPAROUS Zygote- Product of fertilization Embryogenesis- formation of embryo from zygote. Zygote & Embryogenesis POST - FERTILIZATION EVENTS In plants, zygote develops ino embryo, ovules into seed and ovary into fruit Two stages of embryogenesis – cell division & cell differentiation REPRODUCTION IN ORGANISMS ASEXUAL Life Span: Period from birth to natural death of an organism Fertilization in Humans Underground shoots which have one or more buds. BULB