Sexual and Asexual Reproduction • Now we are going to discuss how cells reproduce to make new cells and keep us alive and how humans and plants make gametes (sex cells) for sexual reproduction. • We will also talk about the reproductive systems of males and females and fertilization and development of humans. • Then we will talk about heredity and how our genes are expressed to make us who we are. Organisms can reproduce offspring in one of two ways: 1. Asexual reproduction – requires no fertilization, there is only one parent - occurs mainly in bacteria, fungi, plants, protists, lower plants and animals. - reproduction is quick and often produces a large number of offspring -Several types of asexual reproduction: binary fission, budding, spore formation, regeneration, and vegetative propagation 2. Sexual reproduction – The production of offspring from the union of two sex cells, one from each parent - the genetic makeup of the offspring is different from that of either parent - requires fertilization – the union of male and female sex cells Something to think about Daphnia - reproduce parthenogenetically in the spring to end of the summer - Young are small copies of the adult. Mature females are able to produce a new young about every ten days under ideal conditions. - The reproduction process continues while the environmental conditions are good. When winter approaches or in drought conditions or at times of other harsh environmental conditions, production of new female generations cease and parthenogenic males are produced. - Males can fertilize the female eggs. The eggs are protected from harsh environmental conditions until the more favourable times, such as spring, when the reproductive cycle is able to take place once again. Daphnia • We will return to sexual and asexual reproduction after we discuss how cells make new cells and how cells make sex cells.