Notes – Chapter 21-22 – Plants – Kingdom Plantae

Plant Adaptation to Life on Land

•Plants need water and minerals

•Usually get water and minerals from soil

•Most fruits, leaves, and stems are covered with a protective, waxy layer called the cuticle.

•Leaves are the area in which photosynthesis usually occurs

The lives of plants include two stages, or alternating of generations as a gametophyte (haploid) and a sporophyte (diploid)

**In their haploid phase (gametophyte stage) haploid organisms produce haploid spores (a unit of sexual reproduction) that undergo mitosis. These spores can fuse with each other or with another plant’s spore (sexual reproduction) to create a zygote.

**The fertilized zygote from the gametophyte generation develops into a sporophyte, which has diploid cells. The cells of the sporophyte undergo meiosis to create haploid cells which develop into gametophytes, thereby starting a new phase in the alternation of generations and bringing the organism completely through the alternation of generations, from gametophyte to sporophyte and back again. (See below)

Vascular plants vs. non-vascular

Non-Vascular

  • Have NO true roots or stems; unlike trees, they lack water conducting tissues(xylem and phloem)
  • Can reproduce asexually when their spores fuse but usually reproduce sexually
  • In sexual reproduction they have to have a film of water (male sperm have to swim to female egg)
  • Fertilized egg, the zygote, undergoes mitosis and is diploid, a sporophyte; becomes a stalk attached to the haploid gametophyte
  • They are very small and includes , moss, liverworts and hornworts (see PowerPoint)

Vascular Plants

  • Have tissue that will conduct water from roots to leaves
  • Xylem tissue conducts water and minerals (See PowerPoint)
  • Phloem tissue transfers carbohydrates like sugars for the plants food (See PowerPoint)
  • Includes plants that produce seeds and those that do not
  • Non-seed plants like ferns, club mosses, horsetails
  • Seed plants – seeds contain an embryo, seed coat and food supply
  • Gymnosperms that produce “naked seeds” on cones not covered in a fruit; trees called conifers like pine trees
  • Angiospermsare all plants and trees that produce flowers and have covered seedsprotected inside of a fruit
  • Sexual Reproduction  the zygote will undergo mitosis and becomes an embryo in a seed that germinates (sprouts) and eventually becomes a seedling plant

Monocotyledons (monocots) vs. Dicotyledon (dicots)

Dicots

  • A major group of flowering plants (angiosperms)
  • The plant embryo has 2 cotelydons (Looks like a pinto bean cut in two pieces)that supply food to the embryo
  • Maple trees, oak trees, most flowers, beans, magnolia trees, beech trees willows just to name a few!

Monocots

  • Flowering plants
  • One cotyledon surrounds the embryo
  • Endosperm provides food for the embryo
  • Corn, grasses, lilies, rice, wheat, orchids

Germination of a Seed

First the young root appears. / The skin splits and the shoot straightens, pulling the cotyledons with it. / The main root gets bigger and grows side roots, and the first leaves appear.

Co-evolution of two species alongside each other

  • an extreme example of mutualism
  • Evolutionary influence between two species (the evolution of two species totally dependent on each other).
  • Each of the species exerted selective pressure on the other, so they evolve together.
  • Plants and pollinators is an example.
  • The plant and the pollinator benefit each other.
  • The plant expends less energy on pollen production and instead produces elaborate flowers, nectar, and/or odors.
  • An organism like a honeybee is attracted to the nectar and then becomes dependent on a flower’s nectar and the flower will then become dependent on the pollinator for pollination

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