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HAPLOID GAMETOPHYTE. “The haploid, or gametophytic generation, begins after meiosis with spores that undergo mitosis and differentiate into either a pollen grain (male gametophyte) or an embryo sac (female gametophyte). The male and female gametophytes are derived from specialized spore-forming cells within the reproductive organs of the flower.” http://www.jstor.org/stable/pdf/2885440.pdf?seq=1#page_scan_tab_contents View in LinkedIn

ALTERNATION OF GENERATIONS. “The flowering plant life cycle is divided into haploid and diploid generations that are dependent on each other.” https://lnkd.in/g_k-4-g View in LinkedIn

TWO PHASES. “Most differentiation events in higher plants occur continuously in the postembryonic phase of the life cycle. Embryogenesis in plants, therefore, is concerned primarily with establishing the basic shoot-root body pattern of the plant and accumulating food reserves that will be used by the germinating seedling after a period of embryonic dormancy within the seed.” https://lnkd.in/g_k-4-g View in LinkedIn

CONSERVED. “Regardless of the appearance of the adult plant, the shoot meristem is organized essentially the same way in different plant species.” http://ac.els-cdn.com/0092867495900659/1-s2.0-0092867495900659-main.pdf?_tid=4d4ebb00-9318-11e7-86e1-00000aacb362&acdnat=1504712004_432302d5e397300b77a7d0a78440aca5 View in LinkedIn

PLANT “EMBRYOGENESIS in essence organizes two groups of stem cells at the opposite ends of the body axis, the primary meristems of the shoot and the root. These meristems then add new structures to the seedling, thus generating the species-specific adult form during postembryonic development.” http://ac.els-cdn.com/0092867495900659/1-s2.0-0092867495900659-main.pdf?_tid=4d4ebb00-9318-11e7-86e1-00000aacb362&acdnat=1504712004_432302d5e397300b77a7d0a78440aca5 View in LinkedIn

EMBRYOGENESIS DIFFERENCES. “Pattern formation in animals is largely confined to embryogenesis such that the future adult form is represented in the body organization of the mature embryo. By contrast, plant embryogenesis produces a juvenile form, the seedling, that lacks most structures of the adult plant.” http://ac.els-cdn.com/0092867495900659/1-s2.0-0092867495900659-main.pdf?_tid=4d4ebb00-9318-11e7-86e1-00000aacb362&acdnat=1504712004_432302d5e397300b77a7d0a78440aca5 View in LinkedIn

STEPPED STRATA. "Such a recombination restriction occurred in a stepwise manner along most of the sex chromosomes in parallel in birds and mammals (creating so-called “evolutionary strata”), apart from small pseudoautosomal regions (PARs) that maintain recombination." https://lnkd.in/gxyp7ei View in LinkedIn

TWO SYSTEMS. "Genetic sex-determining systems in vertebrates include two basic types of heterogamety, which are represented by the XX/XY and ZZ/ZW types. Both types occur among amphibian species." https://lnkd.in/gFCg7HY View in LinkedIn

EVOLUTION. "Sex chromosomes originate from ordinary autosomes. Ancient sex-specific W or Y chromosomes, like that of female chicken or those of male mammals, usually have lost most functional genes, owing to a loss of recombination with their former homologs, the Z or X chromosomes." https://lnkd.in/gxyp7ei View in LinkedIn

FAST EVOLUTION. "Structurally, sex chromosomes are the most rapidly evolving parts of the genome in many groups of animals." https://lnkd.in/g2CPWtY View in LinkedIn