FRST 200 Lecture Notes - Lecture 5: Gametangium, Gametophyte, Genome Size
Document Summary
Many adaptations may no longer be adaptive might get used for something else. Species disappearing faster than we can discover. Gene numbers may roughly reflect organismal complexity but genome size does not. Genome duplication in the last 100 million years (extra copies) Symbiosis has provided radically new designs (new parts) leading to radically new directions. Evolution is not particularly linear or sequential process. it"s more like a bushy shrub. Advanced characters may be found in different groups need not go together. Evolution can go backwards (simplification) and can repeat itself (within different lineages, or in a single lineage). insect pollinated to wind pollinated back to insect pollinated. Pre-existing adaptations/structures are often modified into new addition/structures in whole or in part (flower parts, are all modified leaves, thorns) Increasing dominate of the sporophytic generation over the gametophytic generation: alternation of generations moss fern gymnosperm angiosperm. Sperm and eggs develop in gametangia but zygote germinates by meiosis no sporophytic embryo.
