Aristotle studied developing organisms, among other things, in ancient Greece, and his writings shaped Western philosophy and natural science for greater than two thousand years. He spent much of his life in Greece and studied with Plato at Plato's Academy in Athens, where he later established his own school called the Lyceum. Aristotle wrote greater than 150 treatises on subjects ranging from aesthetics, politics, ethics, and natural philosophy, which include physics and biology. Less than fifty of Aristotle's treatises persisted into the twenty-first century. In natural philosophy, later called natural science, Aristotle established methods for investigation and reasoning and provided a theory on how embryos generate and develop. He originated the theory that an organism develops gradually from undifferentiated material, later called epigenesis.
Menopause is defined as the point in time exactly twelve months after a female has had her last menstrual period, or shedding of the lining of the uterus. As a female ages, the hormone levels that drive menstruation decrease, beginning the process of perimenopause, which eventually leads to menopause and can result in various symptoms including depression, difficulty sleeping, and hot flashes, or abrupt feelings of heat typically in the upper body. Once a female reaches menopause, those symptoms typically subside, but after menopause, the risk of other health conditions such as osteoporosis, or brittle bones, increases. At least since the fourth century BCE, researchers understood that menopause occurred in females but held many negative ideas and misconceptions about the process, which resulted in stigma that left females uninformed about what happened to their bodies as they aged. Research on and perceptions towards menopause evolved over the twentieth century, and as of 2024, researchers understand it as a typical part of aging and development in females, marking the end of their reproductive years.