zygote diploid 2n cells from the single celled zygote stage onward cells

Zygote diploid 2n cells from the single celled zygote

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zygote: diploid 2n cells) from the single celled zygote stage onward, cells undergo mitosis to increase the number of cells in the maturing individual (multicellular individuals; diploid 2n cells) o The life cycle of fungi (bread mold); representing simple life cycle for multicellular sexually reproducing haploid organism Carrying one copy of genome, multiple rounds of asexual reproduction possible, all cell divisions occur by mitosis (haploid 1n cells of hyphae) Brief intergenerational zygote stage: fusion of compatible hyphae (plasmogamy and karyogamy) to form a zygote-like structure (diploid 2n zygote) Zygotic meiosis haploid 1n spore Multiple rounds of asexual reproduction possible, all cell divisions occur by mitosis (haploid 1n cells of hyphae) o The life cycle of plants (dioecious flower); representing a complex life cycle for multicellular, sexually-reproducing, organism with alternation of generations Multicellular sporophyte (diploid 2n cells) undergo meiosis to produce spores Unicellular spores undergo mitosis to increase the number of cells in the maturing gametophyte (multicellular gametophyte, haploid 1n cells) Mature gametophyte produces gametes by mitosis (unicellular gametes) Gametes fuse during fertilization to become a zygote (unicellular zygote) multicellular sporophyte (diploid 2n cells) Specialized cells undergo meiosis to produce spores (unicellular spores of gametophyte (haploid 1n cells) Allocation Trade-offs, costs & benefits, constraints o Whether or not a particular life-history trait is favored by natural selection depends on the benefit/cost ratio o “there is no free lunch” meaning no organism can invest unlimited amounts of energy in growth and reproduction… “a jack of all trades is a master of none” o trade-offs occur when organisms allocate their limited energy or other resources to one structure or function at the expense of another o Trade-off between size and number of offspring (offspring or propagule size- number tradeoff)
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