Darwin (1868) was also aware of the prolonged sperm storage in certain insects (below). There were other significant discoveries in reproduction that Darwin must (or ought to) have known of, including: (1) von Baër’s (1827) discovery of the mammalian ovum and his later description of sperm–egg interactions in sea urchins (von Baër, 1847); (2) Wagner’s (1837) documentation of the extraordinary diversity of sperm size and shape; (3) von Kölliker’s (1841) discovery that spermatozoa need to make contact with

the egg if fertilization is to occur; (4) rather later, Hertwig’s (1876) demonstration that fertilization in sea urchins involves the fusion of male and female nuclei. If he did not obtain it directly, Darwin’s most likely conduit for this type of anatomical and physiological AZD1152-HQPA cost information is Thomas Huxley. Ku-0059436 research buy Not only did Huxley receive lectures from some of the key players, like Thomas Wharton, describing the new German cell theory, fertilization and embryo development (Desmond, 1994, p. 26), Huxley later translated into English several major German zoology text books, including Kølliker’s (1853)Manual of Human Histology, which contains

a very comprehensive description of the male and female reproductive system, including this: Nor, from the experiments of Prévost, Dumas, Schwann, and Leukart, and the later researches of Newport … can the least doubt be entertained that they [spermatozoa] are the true impregnating agent, and for the purpose of impregnation must necessarily come in contact with the ovum’. Because Darwin had access to up-to-date information on sexual reproduction, including the processes of insemination, sperm function and fertilization, it seems at first sight unlikely that ignorance could account for his reluctance to explore the evolutionary implications of female promiscuity. On the other hand, if one reads MCE the section in Variation (1868, p. 352) on sexual reproduction in

relation to pangenesis, it is easy to see how Smith (1998) thought Darwin confused: The union of the two sexual elements seems at first sight to make a broad distinction between sexual and asexual generation …. [But] the now well-ascertained cases of Parthenogenesis prove that the distinction between sexual and asexual generation is not nearly so great as was formerly thought; for ova occasionally, and even in some cases frequently, become developed into perfect beings, without the concourse of the male’. Yes – parthenogenesis must have been confusing. Why the [female] germ … ceases to progress and perishes, unless it be acted on by the male element; and why conversely the male element, which in the case of some insects is enabled to keep alive for four or five years … .