🌿 Alternation of Generations in Plant Groups Bryophyta • Pteridophyta • Gymnosperms • Angiosperms Alternation of generations is the life cycle in which plants alternate between a haploid gametophyte (n) and a diploid sporophyte (2n). All four groups show heteromorphic alternation of generations, but the dominant generation changes during evolution. 🌍 Bryophyta (Mosses & Liverworts) 🔹 Dominant generation: Gametophyte (n) 🔹 Sporophyte: Dependent on gametophyte Details: Green, leafy/thalloid plant = gametophyte Sex organs: Antheridia & archegonia Sporophyte differentiated into foot, seta, capsule Spores formed by meiosis in capsule Fertilization requires water 📌 Example : Funaria, Marchantia 🌱 Pteridophyta (Ferns & Allies) 🔹 Dominant generation: Sporophyte (2n) 🔹 Gametophyte: Independent (prothallus) Details: Fern plant = sporophyte Sporangia on sporophylls produce spores Spores form prothallus (gametophyte) Prothallus bears antheridia & archegonia Fertilization re...
🌍 “Drosophila of Algae” 💥 Chlamydomonas reinhardtii is called the Drosophila of the algal kingdom. 🔬 Why Chlamydomonas reinhardtii ? Unicellular & haploid → easy genetic analysis Grows fast in lab culture Excellent model for photosynthesis Used to study flagella, chloroplast genes & mutations 🍄🟫 “Drosophila of fungi” 💥The “Drosophila of fungi” refers to Neurospora crassa. Why Neurospora crassa i s called the Drosophila of fungi? Just as Drosophila melanogaster is a model organism for animal genetics, Neurospora crassa is the model organism in fungal genetics. Key reason : Haploid organism → mutations are easily expressed Short life cycle Easy to culture on simple media Well-studied genetics Used by Beadle and Tatum to propose the One Gene–One Enzyme hypothesis Importance : Fundamental studies in genetics and molecular biology Understanding gene–enzyme relationships Widely used in biochemical and genetic research 🌲"Drosophila of plant kingdom" 💥In pla...