Science!
A: The adult of the species (a diploid sporophyte) has an androgynous form, and lives in peace and harmony, aloof from the squabbles which emanate from sexual reproduction. B: When the time to reproduce arrives, spore buds (sporangia) sprout on the underside of her frond-arms, and release their contents. C: These spores are produced by meiosis, and are therefore haploid, like our sperm and eggs (our gametes). Yet this is not when sex occurs.
H: The baby sporophyte then grows right out of the gametophyte, doing away with the whole birth business. So I hope you can see that this new way of life has its advantages. We may miss out on sex. It may take some time to get used to seeing fields of genitalia cross-fertilising through the day. But think of all the time you’ll save…for more important stuff, like the interwebs. We can but dream. O
D: Instead the spores sprout and grow by mitosis into sexual organs, called gametophytes. E: The gametophytes carry both male and female genitalia. However, self-fertilisation is prevented because the sexual organs on the one gametophyte do not mature in unison. F: The male sexual organs (antheridia) release motile sperm. That’s right, both human and ferns, and our whimsical Homo pteridophytus, all have little swimmers. Bet you didn’t know plants did that! G: They swim up the archegonium and fertilise the egg. At this point a diploid zygote is formed.
Volume 79, Issue 4
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