4 5 Crucial Seed Plant Adaptations 1. Reduced gametophyteNow gametophyte is dependent on sporophyteUnlike in ________, where ________________2. HeterosporesMegaspores = produce female gametophyte eggsMicrospores = produce male gametophyte sperm3. Ovules and production of eggsProtection of egg and developing zygoteIncreases reproductive fitness (likelihood of successful production of offspring)
5 4 & 5 Crucial Adaptations 4. Pollen & sperm production 5. Seeds Pollen grain contains sperm nucleiPollen grain has waterproof coatingNo more water needed for sperm to travel to the eggNow it is the wind that disperses sperm5. SeedsSeeds > sporesMulticellularLayers of protective tissueStored energy for the development of the embryo
8 Gymnosperms “naked” seeds Conifers (Coniferophyta) Not enclosed in ovaries (fruits)Seeds are typically in cones that allow for airborne dispersalConifers (Coniferophyta)Pines, spruces, firs, and redwoods
9 Conifers have Ovulate & Pollen cones Megasporangium undergoes meiosis = 4 haploid cells, but only 1 becomes megasporeMultiple archegonia are produced inside each gametophyte = multiple eggs producedOnly 1 fertilized egg develops into the embryo, others dissolve
10 Gymnosperm Life Cycle Notes Megasporangium (2n) – produces 4 megaspores (n)Via meiosis3 spores (n) dissolve leaving 1 megasporeMegaspore (n) – develops into the female gametophyte (n)Female gametophyte contains multiple archegoniaMultiple egg productionSperm nuclei from pollen fertilizes egg(s)Only one fertilized egg is able to survive
11 Questions?What is the correct term for the pine tree? Diploid or haploid?What is the correct term for the cones on the pine tree? Diploid or haploid?Yellow cones are_______, pine cones are _______How is the pollen dispersed?What does the pollen produce?
12 What becomes of … ? Megasporangium? Megaspore? Egg, if fertilized? Ovule?Female gametophyte?
13 Angiosperms Fruits, Flowers, and double Fertilization 90% of all plant speciesSeeded + VascularFlower – structure for sexual reproductionFruits – mature plant ovaries (yes, you are eating plant ovaries)Double fertilization1 sperm fertilizes egg = zygote1 sperm combines with 2 nuclei in ovule = endosperm
14 Angiosperms – 2 classes Monocots Dicots (Eudicots) Monocots have 1 cotyledon (structure that nourishes the developing plant)Parallel veination in leavesOrchids, lillies, and grassesDicots (Eudicots)2 cotyledons in the seedNetted veination in leavesRoses, peas, beans, oaks
15 Stamen = Male-- Anther + filament-- Microspores produced in antherCarpel = female-- Ovary-- Stigma, style-- Megaspores produced in Ovules inside OvaryPetals – attract pollinators
16 Fruits -- Can be wet or dry -- Wet fruits – oranges, plums, grapefruit, tomatoes-- Dry fruits – Beans, nuts, & grains