Final answer:
Without meiosis, higher organisms would be unable to undergo sexual reproduction, leading to a lack of genetic diversity and drastically different reproductive strategies similar to some plants and without distinguishable lineages. Meiosis is crucial for genetic variation and gives sexual reproduction significant advantages in evolution and population survival.
Step-by-step explanation:
If meiosis did not exist in cells of the reproductive systems of higher organisms, there would be significant implications for how these organisms reproduce and evolve. Without meiosis, organisms would not undergo sexual reproduction as we understand it. Instead, they might reproduce asexually, through a process similar to mitosis, where each parent or a single individual would produce identical offsprings. This would result in a lack of genetic diversity, as the only source of variation would be mutations. In contrast, sexual reproduction through meiosis combines different genomes and introduces new genetic combinations due to crossovers and random assortment, effectively increasing the genetic diversity within the population, which is vital for the adaptation and survival of the species.
Moreover, an organism's sexuality, including the formation of specialized sperm and egg cells, would not be defined in the same way. Instead, beings would release haploid spores that grow into new individuals, a form of reproduction seen in certain plants. Such a life cycle would create beings that are vastly different from humans in structure and lifecycle, leading to a non-distinguishable lineage where the identification of parents or offspring would be impossible.
The evolution of meiosis has been a complex process that biologists continue to study. Despite meiosis being a complex series of events, it is crucial for understanding the evolution of sex and the advantages it provides. Current research into protists and their various forms of meiosis helps us understand when and how meiosis evolved. The introduction of sexual reproduction and meiosis has been so vital for multicellular organisms that completely asexual multicellular organisms are extremely rare.