Hello, everyone. I hope everyone is ready for the new school year. This semester, I will be taking Developmental Biology. While the class has only just begun, it appears that this class will focus on the Developmental Biology of animals. For instance, there are four stages of development for animals: fertilization/zygote formation, blastula formation/zygote cleavage, gastrulation/cell rearrangement, and finally, organ development. It would be very interesting to see the developmental stages of plants and fungi, if this area is applicable in the same way it is to animals. Thank you for any helpful comments and suggestions in advance. Also, since the university has started, I probably will not be on the iNaturalist Forum as often as I normally would.
Plants and fungi have very different developmental pathways and don’t go through the stages you list for animals with the exception of fertilization/zygote formation and even that is not quite true for many fungi. Fungi have the simplest development from spore to hyphae and the interesting development happens when they form the fruiting bodies.
Plants have a more complex development than fungi and there is certainly more variety but their development from spore and/or seed to adult looks nothing like the development of animals. For instance, a fern goes from a spore that it produces to a gametophyte plant that lives in the soil to producing eggs and sperm that, when the egg is fertilized, will produce the “adult” plant called a sporophyte.
Animal development is also highly variable and that is probably where you will spend your time looking at not only the stages of development but how that development varies between the more primitive diploblastic animals to the more complicated triploblastic ones (the protostomes and deuterostomes).
So to make the answer shorter, the development of plants, fungi, and animals are very different and they don’t follow the same developmental patterns or life stage patterns.
Fungi really are bizarre in terms of their life cycles. @cmeckerman is right that there isn’t really an analogy to the development you describe for animals. For the higher fungi, “fertilization” can occur in a manner like sperm fertilizing an egg, which is to say one small partner and one larger (small spores acting as spermatia landing on trichogynes, for instance), but it can also occur between more or less equal partners (two interacting, sexually compatible mycelia). As a short aside, Ascomycetes and Basidiomycetes aren’t really diploid, they are dikaryotic; the DNA from both parents are kept in two separate nuclei, which means that they have to do cell division differently, resulting in “clamp connections” in Basidiomycota and “croziers” in Ascomycota. In Ascomycota, dikaryotic cells are very limited in extent; like fruiting plants, most of the ascomata (the structural outside parts) are actually composed of haploid hyphae from one of the parents. The rest of it (the inner part that produces sexual spores) is dikaryotic. Basidiomycetes do it a little differently, though; the whole basidiome is dikaryotic, not just the cells making spores. Another interesting thing is that the asexual portion of the life cycle in fungi is potentially very rich, containing many different stages. Some fungi don’t have a sexual portion of their life cycle at all, as far as we know, and others don’t have much of an asexual portion. For really complicated basidiomycete life cycles, look up rust fungi. For complicated ascomycete life cycles, there really are some weird ones. For instance, in the genus Tympanis, each spore bearing cell (ascus) creates eight spores (typical for ascomycetes; a round of meiosis followed by mitosis, but they can produce as few as one sexual spore and as many as hundreds of them per ascus). Before they are even ejected, each spore produces short hyphae and directly from each spore, starts producing hundreds of little asexual spores (conidia), so that ultimately, each ascus has eight balls of hundreds of tiny conidia. The balls of conidia are actually what get shot out into the world. Once they land, they produce hyphae and become a mycelium, and can form asexual spore-producing structures called pycnidia, which further produce another type of conidia.
On another tangent, “sex” in fungi is also weird. Instead of really having sexes, fungi are said to have “mating types,” with some fungi having hundreds of different mating types, most of which are compatible. How they can work is also weird; for instance, in Ustilago maydis, one of the mating type loci has two variants that actually code for two halves of a necessary protein for the fungus to infect its host, Zea mays. So, it isn’t that the same mating types can’t form a single dikaryotic mycelium, but if so it will just starve.
In short, fungi are really weird, and I am sorry if I got off topic here.
I found a good article, even though it is on Wikipedia, about the embryonic development that occurs inside seeds (“Seed.” Wikipedia, 2021, https://en.wikipedia.org/wiki/Seed. Accessed 27 January 2021).
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