Infant development experts say that teething usually starts when your baby is around four months old, and continues until he or she is about two years old, at which time you get a reprieve until about five years old when the baby teeth start being replaced by grown-up teeth.
Quick Answer. Meiosis contributes to genetic variation by creating new groups of genes, according to the University of Miami Miller School of Medicine. The new groups are created when chromosomes passed down from a mother and father share instructions encoded into genes.
During anaphase of meiosis II, the centromere joining each chromatid pair dissolves, creating two chromosomes of each type. The outcome of which chromosome will go to which gamete is random, so that each gamete has a potentially unique combination of genetic material. Fertilization Fertilization creates genetic diversity by allowing each parent to randomly contribute a unique set of genes to a zygote. While fertilization is not part of meiosis, it depends on meiosis creating haploid gametes. The fertilized cell restores the diploid number. Without meiosis, the number of chromosomes per cell would double in each generation of offspring, leading to unstable conditions that could threaten the viability of a species.