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
4. STUDY


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
-Eukaryotic
-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

Reproduction: 

• 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,

Mark

Next Scribe:
 Charlie