West Texas Pine Harvest and Alternation of Generations

A rant about West Texas Pines and the sand blazing star. At the 40 minute mark we begin our dive into the convoluted, confusing but utterly cool phenomenon of Alternation of Generations we talk mostly about Bryophytes (mosses and liverworts) and Lycophytes ("spikemosses" and "clubmosses"), and the ferns, but not gymnosperms or angiosperms). This turns into more of a "lesson" on the subject than a podcast episode.

Key terms to remember :

Gametophyte (haploid), Sporophyte (diploid)
Haploid - 1 set of chromosomes aka 1 copy of the genome
Diploid - 2 sets of chromosomes aka 2 copies of the genome (one as a backup copy)
Meiosis (takes a diploid cell and produces haploid daughter cells, two of which later come together to form a diploid zygote/sporophyte)
Mitosis (Cell divides and produces cells identical to whatever the parent cell was, whether that parent cell was haploid or diploid. Mitosis doesn't reduce the chromosome number by half). Meiosis is synonymous with sex/reproduction/the production of haploid cells).

Evolutionary lineages referenced in this episode and their phylogenetic classification:

Bryophytes (An informal paraphyletic classification used to refer to the non-vascular Phyla Anthocerotophyta (hornworts), Marchantiophyta (liverworts), and Bryophyta (mosses)

Lycophytes : Class Lycopodiopsida, contains 3 orders: Lycopodiales (1 Family : Lycopodiaceae; 3 Subfamilies : Huperzioideae, Lycopodielloideae, Lycopoideae), Selaginellales (1 family : Selaginellaceae), & Isoetales (1 family : Isoetaceae).

Ferns : Class Polypodiopsida.
Contains 4 Subclasses : Equisetidae (Horsetails), Marattiadae (Marratioid Bastards including Angiopteris evecta with 20' long fronds), Ophioglossidae (Whisk Ferns, Grape Ferns, Moonworts), and Polypodiidae (Leptosporangiate Ferns, aka the "classic" ferns including the majority of what people think of when they think of ferns including Maidenhairs, Cinnamon Ferns, Sensitive Ferns, Filmy Ferns, Forked Ferns, Cheilanthoid "Desert" Ferns, Mosquito Ferns, Tree Ferns, Aspleniums, etc.


THUMBNAIL : Archegoniophore (haploid) and Non-photosynthetic Sporophyte (Diploid) of the Baja California liverwort Asterella palmeri, photo by Ken-Ichi Ueda