Sunday, March 11, 2012

Scribe Post 3/9/12

Today in class we:

-Measured/watered Fast Plants
- Researched in IMC for Wildlands project

HW: 1. Read CH 28 by Monday
2. bring TEXTBOOK to class ALL next week!
3. wildland project

Chapter 16 Overview:

*The required pages for Chapter 16 are pages 320-334 & 340-341

Why should we study plants?
Provide us with Oxygen, food, clothing, paper, supplies, energy, and sustain life.

Plant Kingdom is: -Multicellular
-Autotrophic (by photosynthesis)

Land Adaptations: 

1. Mycorrhizae: root-fungus combinations-fungi absorb water and minerals from soil, plant sugar nourishes fungi

2. Stomata: Microscopic pores through leafs surface exchange CO2 and O2

3. Cuticle: Waxy layer coating leaves and other aerial parts to help retain water

4. Lignin: Chemical which hardens cell walls

5. Roots and Shoots

6. Xylem tissue: (transports water up) and Phloem tissue (transports food around)

7. Protected Embryo: gametangia -a jacket of protective cells surrounding a moist chamber where gametes can develop without drying out

8. Seed Dispersal: Rely on wind or animals

Origin of Plants from Green Algae
Charophyceans: group of multicellular green algae; closest to plants (in evolution)

Four Major Periods of Plant Evolution:
1. Bryophytes (mosses)
2. Ferns
3. Gymnosperms (conifers)
4. Angiosperms (flowering)

1. Bryophytes- Mosses (many plants growing in a tight pack)

Key Characteristics:

  • No cuticle
  • Need water to reproduce 
  • Flagellated sperm
  • No vascular tissue
  • Like damp/shady places
Green Spongy plant = Gametophyte (male & female are separate plant shoots)(n)
Taller brown shoot with a capsule; grows out of gametophyte = Sporophyte (2n)
Alternation of Generations:

  • 2 Generations that "take turns" producing each other
  • Gametophytes produce eggs and sperm; unite to form zygote which then forms new sporophytes
  • Sporophytes produce spores
  • Spores develop new organism without uniting
  • New organism produces gametophytes again
  • Process repeats
  • ***Gametophyte = Larger more obvious plant in mosses
2. Ferns

Key Characteristics: 
  • most in tropics/temperate woodlands
  • vascular tissue present (Xylem and Phloem)
  • Sperm flagellated
  • ***seedless (have spores)
Alternation of Generations:

  • Sporophytes are diploid and gametophytes are haploid

  • ***Sporophyte is the dominant stage in ferns (Gametophyte for mosses)
  • Heart Shaped gametophyte = prothallus
3. Gymnosperms:

Key Characteristics: 
  • Cone Bearing
  • Life cycle on dry land
  • oldest organisms on earth
  • retain leaves throughout year
  • thick cuticle
  • source of wood and paper
  • Pollen contains cells that develop into sperm
  • Wind carries pollen to female cones
  • Eggs develop in female cones
  • ***Evolution of a seed- a plant embryo packaged along with a food supply without a protective coat
  • Bear seeds naked on cone scales
  • Seeds germinate under favorable conditions
  • 2 types of cones
  • Female cone is most familiar (hard, woody, scaly)
  • Male cone is smaller; lower on the tree; release pollen
4. Angiosperms:

Key Characteristics:
  • Dominate most regions
  • 250,000 Species
  • Vascular tissue
  • ***Evolution of a flower = Responsible for unparalleled success
  • Flowers display male + female parts
  • insects/animals transfer pollen
  • Flower: Short stem with modified leaves: sepals, petals, stamens, carpels
Parts Of A Flower + Function:

Sepals: green, enclose flower before it opens
Petals: Attract insects 
Stamen: Filament (stalk) bearing a sac called anther (male organ in which pollen develops)
Carpel: Sticky tip traps pollen (stigma), 
Ovary: Eggs develop here

Angiosperm Life Cycle:
  • Pollen lands on stigma, tube goes down to ovule
  • Deposits 2 sperm nuclei within female gametophyte = double fertilization
  • One sperm cell fertilizes egg making zygote, developing into embryo
  • Second sperm cell fertilizes another female gametophyte cell which develops into a nutrient-storing tissue called endosperm

Hope this helps summarize chapter 16 and the notes we did in class.

See you in class,
Next Scribe:

1 comment:

  1. This was such a good post! The pictures were helpful and all of the notes were nicely consalidated. Great job