In a nutshell
AP Biology 2007-2008 Plant Diversity mosses ferns conifers flowering plants
Bryophytes Pteridophytes Gymnosperm Angiosperm non-vascular seedless pollen & flowers & fruit land plants vascular plants “naked” seeds flowers & fruits
pollen & seeds
vascular system xylem cells AP Biology common ancestor tracheids Animal vs. Plant life cycle Animal Plant
diploid diploid multicellular multicellular individual sporophyte 2n mitosis 2n mitosis meiosis fertilization meiosis gametes spores 1n 1n
fertilization mitosis mitosis haploid haploid unicellular multicellular gametes gametophyte 1n 1n
AP Biology alternation of generations Bryophytes Mosses & liverworts
non-vascular
swimming sperm diploid multicellular dominant haploid gametophyte sporophyte dependent sporophyte mitosis 2n spores for reproduction fertilization meiosis gametes spores 1n 1n
mitosis mitosis haploid multicellular gametophyte 1n alternationAP Biology of generations Pteridophytes Ferns
vascular
swimming sperm diploid multicellular dominant sporophyte sporophyte independent gametophyte mitosis 2n fragile fertilization meiosis spores for reproduction gametes spores haploid 1n 1n
archegonia mitosis mitosis haploid multicellular gametophyte antheridia 1n alternationAP Biology of generations Gymnosperm Conifers
vascular
pollen (sperm) diploid multicellular dominant sporophyte sporophyte dependent reduced gametophyte mitosis 2n cones, seeds for reproduction fertilization meiosis gametes spores 1n 1n
mitosis mitosis haploid female multicellular gametophyte male 1n
AP Biology Angiosperm Flowering plants
vascular
pollen (sperm) diploid multicellular dominant sporophyte sporophyte dependent reduced gametophyte mitosis 2n flowers, fruits, seeds for fertilization meiosis reproduction male gametes spores gametophyte 1n 1n in pollen (haploid) mitosis mitosis haploid multicellular female gametophyte gametophyte in ovary 1n (haploid) AP Biology Angiosperm: flowering plants
AP Biology polar Angiosperm life cycle nuclei pollen male grains gametophyte egg in pollen cell (haploid)
fertilization
female gametophyte in ovary (haploid)
sporophyte in seed AP Biology (diploid) Flower Modified shoot with 4 rings
of modified leaves Stigma Anther Style Carpel sepals Stamen Ovary Filament petals
stamens male pollen sepals Petal petals carpel stamens Ovule female carpel Sepal egg
AP Biology What’s the adaptive Double Fertilization advantage?
pollen grain
sperm cells pollen tube pollination
ovule Endosperm (3n) ovary food in seed grains endosperm (3n) beans coconut milk pollen tube polar nuclei zygote (2n)
AP Biology Seed & Plant embryo seed coat Seed offers…
protection for endosperm embryo 3n
stored nutrients for growth of cotyledons embryo embryo
cotyledonscotyledons == “seed”“seed” leaves,leaves, firstfirstAP Biology leavesleaves ofof newnew plantplant Identify the flower structures…
AP Biology Flower variations
AP Biology seeds Corn reproduction flowers & seeds
silk→stigma & style tassel pollen
AP Biology female→carpel male→stamens Co-evolution: flowers & pollinators
How a bee sees a flower…insects see UV light = a bulls-eye to the nectar
AP Biology Angiosperm: fruiting plants
AP Biology Other fruits…
AP Biology Fruit development Peach, plum, apricot, cherry
1 flower : 1 carpel : 1 ovary : 1 seed
AP Biology Fruit development Apple, pear
1 flower : 5 carpels : many ovaries : many seeds
AP Biology Fruit development Citrus fruit 1 flower : many carpels : many ovaries : many seeds
AP Biology Fruit development Raspberry, strawberry
1 flower : many ovaries : many seeds
AP Biology Seed dispersal Plants produce enormous numbers of seeds to compensate for low survival rate
vast amount of genetic variation for natural selection to screen r-strategy K-strategy
AP Biology Any Questions??
AP Biology 2007-2008