According to Jennifer Welsh for Live Science, amoebas are generally considered to reproduce asexually through a process called binary fission. This describes the act when the nucleus of one cell is spurred to divide into an equal and exact replica of itself within the same cell walls, after which the two nuclei separate into their own individual cells, resulting in two sovereign yet genetically identical amoebas.
Dave Mosher for Scientific American states that modern scientists have recently begun to question whether amoebas are actually purely asexual or if the reproductive behavior scientists have studied in the past is merely the result of controlled laboratory conditions. Scientists believe that all animal life sprung forth from the evolution of single-celled organisms such as amoebas. Most animals reproduce sexually through the act of traditional male and female embryonic insemination. Therefore, Mosher states that at some point within the evolutionary history of animal life, amoebas must have begun to reproduce sexually. Sexual behavior between amoebas has never been observed. If the theory is accurate, it would not indicate that amoebas necessarily reproduced with the use of typical sexual organs but would instead cause scientists to redefine the basic assumptions about which behaviors might define the act of sex.
Asexual reproduction is immediately advantageous because it is quick as an amoeba can essentially make a copy of itself at will; however, this form of reproduction ultimately leads to extinction. Mistakes accumulate in the genome over time; if every individual in the population is an exact copy of the others, eventually they all become contaminated with fatal mutations. Sexual reproduction creates genetic diversity, reducing the possibility of harmful mutations in every individual. Amoebas are able to reproduce in both ways, depending on environmental variables.