120 likes | 135 Views
Explore the advantages and disadvantages of sexual reproduction, including the role of meiosis in producing genetic variation and the different reproductive strategies in plants. Discover how sexual reproduction provides organisms with the necessary variability to survive in nature.
E N D
Sexual Reproduction Advantages and Disadvantages
Sexual Reproduction • This is the process through which two parents cells join to produce offspring. • The sex cells have half the number of chromosomes of a normal cell. • For instance, a cat cell has 32 chromosomes…… • sex cells would have 16 chromosomes (mother) and 16 chromosomes (father)
Meiosis • Meiosis is the process that ensures that a cell produced by sexual reproduction has the correct number of chromosomes. • Unlike mitosis, meiosis involves two series of division.
Meiosis • At the end of meiosis, one cell has produced four cells that each have half the number of chromosomes as the original cell. • Because the original cell in meiosis has different homologous chromosomes, each of the 4 daughter cells will have one or the other of each homologous chromosome. This gives variation to each daughter cell.
Meiosis • In the male, the four cells that are produced are sperm cells. • In the female, the four cells that are produced are egg cells.
Advantage • Advantage: the offspring are not genetically identical to either parent. • Two partners can produce offsprings with different DNA combinations. • This provides the variation needed to help organisms survive in nature.
Disadvantage • Two partners are needed
Asexual and Sexual Reproduction • Some organisms can reproduce by both asexual and sexual reproduction depending on the environment. • If conditions are harsh and large numbers of offspring are needed, asexual reproduction will be the way to reproduction for this type of organism. • However, if environmental conditions are changing, variations in the hereditary information are needed…..sexual reproduction provides more of a benefit for that particular species.
Reproduction in Plants • Almost half of all plants reproduce sexually to make seeds. • Pollen in plants contains the sperm cells and must be carried to the female part of a flower in order to find the egg cell. • The sperm joins with the egg cell and grows into a seed which can become a new plant.
Asexual Reproduction in Plants • They produce branches or buds that spread out around the parent plant and can grow into complete new plants. • Blackberry bushes reproduce by allowing their branches to grow roots wherever the stems touches the ground. They also reproduce sexually by making seeds.