Biology Ch 23 - Plant Evolution

Plants breakdown into

Non Vascular Seedless

Vascular → vascular seedless and vascular tissue with seed (angiosperm & gymnosperm)

Non vascular seedless example

Moss (abt 490 mya)

Vascular seedless

Ferns (370 Mya)

Vascular tissue with seed

Gymnosperm (Conifers)

Angiosperm (Flowers)

Closest living relative to plants

Green Algae → photosynthesis, cannot protect their embryos, require a wet environment

Alteration of Generation

(Animals) Gamete - haploid (1n) → zygote (2n)

(Plants) Gametophyte Generation - Haploid Cells (1n)

Gametophye generation

All the cells in the plant are haploid

Antheridia

Sperm in plants

Archegonia

Egg in plants

Sporophye generation

All the cells in the plant are diploid

Moss life cycle

Gametophyte gen(mitosis) → sperm/egg → zygote (2n) (mitosis) → Sporophyte gen (2n) → sporangium (meiosis) → Spores (1n) →

Fern life cycle

Sporophyte gen (2n) → sporangium (meiosis) → spores (1n) → wind (mitosis) → Gametophyte gen (meiosis) → sperm/egg → zygote (2n) → mitosis →

Mitosis

Clone

Meiosis

Reduction

Gymnosperms

Vascular tissue, has seeds, won’t germinate until the conditions are right (cone bearing) think conifers

Seeded vascular

Gymnosperms & Angiosperms

Gymnosperms Male Gametophyte

Microspore (1n)

Gymnosperms Female Gametophyte

Megaspore (1n)

Conifer : Pine Tree life cycle (Male)

Pollen Cone (2n) → Microspore mother cell (2n) (Meiosis) → Microspore (1n) = Male Gametophyte

Conifer : Pine Tree life cycle (Female)

Seed Cone (2n) → Megaspore mother cell (2n) inside an ovule (meiosis) → 4 Megaspore cells (1n) = Female Gametophyte > 1 becomes Megaspore (egg) → 3 1n Megaspore cells become nutritive tissue surrounding the egg

Angiosperm types

Monocots & Dicots