LIFE 103 1st Edition Lecture 8 Outline of Last Lecture I Mosses I Anatomy II Sequence III Ecology II Ferns and other seedless plants I Anatomy II Other derived traits III Diversity Outline of Current Lecture II A Summary of Life III Key Features of Seed Plant Evolution I Increased dominance of the sporophyte II Appearance of air borne pollen to bring gametes together III Seeds IV Seeds V Gymnosperm Anatomy I Female II Male III Fertilization IV Embryo i Fig 30 6 VI Diversity Current Lecture Seed plants Gymnosperms A Summary of Life I II III IV Reproduce ultimate goal I Eat II Grow III Avoid dying There are tradeoffs you can t be good at everything Natural selection favors organisms that are best at living under current conditions Fig 29 7 Phylogeny tree of plant ancestors These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Key Features of Seed Plant Evolution I II III Increased dominance of the sporophyte I Gametophyte stage is microscopic Appearance of air borne pollen to bring gametes together I Eliminates need for swimming through water Seeds Seeds I II III IV Resistant to harsh conditions Can be dormant until the environment is favorable Allows for wide dispersal Nourish sporophyte during germination and early growth Compare and Contrast Embryos Fern I II III Egg and sperm come together to form a zygote in gametophyte Creates multicellular embryo on gametophyte Sporophyte independent Seed plant I II III Egg and Sperm come together to form a zygote in gametophyte Creates multicellular embryo on gametophyte Sporophyte independent Gymnosperms naked seeds Gymnosperm Female Anatomy I II III Megasporangium diploid tissue where haploid megaspore is formed meiosis Megaspore haploid cell that grows into the female gametophyte including the egg nucleus Ovule megasporangium plus megaspore wrapped in sporophyte s protective cover integument Gymnosperm Male Anatomy I II III Microsporangium diploid tissue where haploid microspores are formed meiosis Microspores develop into male gametophyte Pollen contains the male gametophyte within the tough pollen wall mirrors the ovule of the female Gymnosperm Fertilization I II III IV Pollen released into the air spreads for miles Pollen grain reaches ovule and germinates Pollen tube grows digesting through megasporangium container for the megaspore Pollen tube reaches egg nucleus discharges sperm nucleus into egg nucleus of female gametophyte Gymnosperm Embryo I II III IV V Embryo is sporophyte that develops then pauses diploid Embryo itself is diploid Surrounded by female gametophyte tissue that are food reserves Fig 30 3 Unfertilized ovule into fertilized ovule gymnosperm seed new sporophyte I Seed coat derived from integument II Food supply female gametophyte tissue n III Embryo 2n new sporophyte IV Example pine nut Fig 30 6 IMPORTANT FIGURE I Showcases the process of fertilization through meiosis II Clicker questions What is the Ploidy of the seed embryo Diploid III Where are pollen grains produced Microsporangia IV Male and female classification goes down to gametes egg and sperm Diversity Gymnosperm Phyla I II III IV V Coniferophyta 600 species I Fir pine larch juniper sequoia Cycadophyta 130 species I Palm like leaves with a large cone Gnetophyta 76 species I Oddballs Ginkos 1 species I Example of dioecious separate male and female plants II Female trees produce fleshy seeds that rot and stink Examples I Douglas Fir 1 source of wood in North America II Bristlecone pine among the oldest living organisms III Giant Sequoia among the largest and most troublesome organisms IV Common juniper berries used in production of gin V Cycas revolute leaves like palms VI VII Ginkgo biloba stinky when seeds rot have fleshy seeds Ephedra