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Reproduction Asexual Reproduction Process by which a single parent reproduces by itself. Methods of Asexual Reproduction Binary fission Fragmentation Regeneration Budding Binary Fission Separation of a single cell into two identical daughter cells. Used by most bacteria. Fragmentation The parent breaks into different fragments which eventually form new individuals. Used by flatworms. Regeneration When an animal loses a body part and it can grow a replacement. Used by echinoderms. Budding An offspring grows out of the body of the parent. Used in hydra. Sexual Reproduction Process by which two cells from two different parents unite to produce the first cell of a new organism. Methods of Sexual Reproduction Fertilization Pollination Fertilization The union of male and female gametes to form a zygote. Used by humans. Pollination Fertilization in flowering plants. Asexual vs. Sexual Reproduction Asexual Sexual one parent two parents Usually in single-celled organisms Usually in plants, animals, and other multi-cellular organisms Uses mitosis to reproduce cells Uses meiosis to reproduce Includes binary fission, bacterial conjugation, fragmentation, budding, and regeneration Includes fertilization and pollination. Cell Growth In most cases, living things grow by producing more cells. There are reasons that cells divide rather than growing themselves. On average, the cells of an adult are no larger than those of a child, there are just more of them. The larger a cell becomes, the more demands the cell places on its DNA The larger cell has more trouble moving enough nutrients and wastes across the cell membrane. The ratio of surface area to volume must remain high. Before it becomes too large, a growing cell divides forming two “daughter” cells in a process called cell division. DNA is replicated so that each daughter cell has its own copy