Admit Slip 3. List 3 words you think of when you look at the picture/diagram 2. Write 2 ideas you have based on the picture and your words. If possible, use your words as you write your ideas. 1. Write 1 question you have. Chapter 29: Plant Diversity. How plants colonized land Chapter 29.1.
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Admit Slip 3. List 3 words you think of when you look at the picture/diagram 2. Write 2 ideas you have based on the picture and your words. If possible, use your words as you write your ideas. 1. Write 1 question you have. Chapter 29: Plant Diversity How plants colonized land Chapter 29.1
Plants supply oxygen and are the ultimate provider of most of the food eaten or absorbed by other organisms.
Terminology • -phyte=Plant • Bryo=moss • Ptero=fern • Gymno=naked • Mitosis: division of cells-forms identical copy with full set of chromosomes (2n), body cells • Meiosis: division of cells-forms a cell with a half set of chromosomes (n), sex cells • Haploid: half the total chromosomes for an organism (egg/sperm) • Diploid: full number of chromosomes for an organims (somatic)
Land plants evolved from green algae • Evolved from Charophytes (green algae) more than 500 million years ago. • Evidence for evolution from Charophytes • Both produce cellulose for cell walls the same way • Their peroxisomes have enzymes that reduce effects of photorespiration (unique to both) • Both produce cell plates the same way during cell division • Structure of sperm is closely related • Nuclear and chloroplast genetic evidence suggests close relation
Charophytes Chara Spirogyra Coleochaete
Movement of plants from sea to land • Advantages: • Increased sunlight (unfiltered by water) • More carbon dioxide in atmosphere than water • Soils rich in nutrients • Fewer predators • Challenges • Lack of water • Desiccation • Lack of structural support against gravity
Adaptations of Land Plants • Adaptations in growth • apical meristem: localized region of cell division at tips of roots and shoots • Adaptations in reproduction • alternation of generations • walled spores: protect spores in harsh environments • multicellular gametangia: structures for gamete production • multicellular dependent embryos: transfer of nutrients from tissue to embryo • Adaptations against water loss • Cuticle
Alteration of Generations • All land plants have two multicellular stages • Gametophyte • plant cells are haploid • Gametes are produced • Sporophyte • plant cells are diploid • Divides mitotically • Sporophyte produces spores through meiosis
Alteration of Generations During fertilization: gametes (egg and sperm-both haploid) fuse to form a diploid zygote (sporophyte) Zygote develops in tissues of female parent getting nutrients from it, sometimes called an embryophyte
Gametangia • Plants produce gametes in multicellular structures called gametangia • Female: archegonia-produces a single egg • Male: antheridia-produces many sperm
Chapter 29: Plant Diversity How plants colonized land Chapter 29.2
Bryophytes • Moss • Nonvasular (small size) • Seedless • Life cycle dominated by gametophyte stage • Water required for sperm to swim to the egg during fertilization
Chapter 29: Plant Diversity How plants colonized land Chapter 29.3
Pteridophytes/Ferns • First plants with vascular tissue • Allowed plants to grow tall and gain access to sunlight • Seedless • Require film of water for sperm to reach egg • Life cycle dominated by the sporophyte stage • Meiosis occurs in sporangia producing haploid sporeswhich may grow into gametophytes with anteridia (release sperm) and achegonium (produce egg, house zygote after fertilization)