Transcript Ch22 Diversity of Plants

Plant Diversity
What are Plants?
• Multicellular (made of many cells)
• Eukaryotes (cells have nucleus &
organelles)
• Cell Walls made of Cellulose
• Autotrophs
– Photosynthetic using chlorophyll a & b
Survival
• Plants need 4 things:
1) Sunlight: without light they cannot get
energy
2) Water & Mineral: needed for
photosynthesis
3) Gas Exchange: take in CO2 & let out O2
4) Movement of Water & Nutrients: food
made by plant needs to get to all parts
of the plant
First Plants
• What organism have we
covered that looks like a
plant?
– Multicellular GREEN
ALGAE
– Thought to have started
in the ocean
Mosses & Bryophytes
• Non-vascular Plants
– Don’t have tissues transporting water through
them
• Dependent on Water
– Take in water through osmosis
• Bryophytes Include:
– Mosses, Liverworts, & Hornworts
1) Mosses
2) Liverworts
3) Hornworts
Seedless Vascular Plants
• Include:
– Club Mosses
– Horsetails
– Ferns
• Most numerous
• Have true roots,
leaves, & stems
Vascular Tissue
• Vascular Tissue:
– transfers water & nutrients through the plant
• Traicheids: cells specialized to move water
• Xylem: cells that move water up the plant
• Phloem: cells that move nutrients and
carbohydrates made by photosynthesis
True Integral Parts
• These are the 1st plants to show:
– True Roots: underground organs that absorb
water and minerals
– True Leaves: photosynthetic organs that
contain vascular tissues
– True Stems: supporting structures that
connect roots and leaves; carry water
Seed Plants
• Can reproduce without water! Why?
– They have flowers or cones
– Transfer sperm by pollination
– Embryo is protected in seed
Types of Seed Plants
• Two Types:
– Gymnosperms
• have seeds directly on surface of cones
– Angiosperms (Flowering Plants)
• have seeds that are protected by a layer of
tissue (i.e. Fruit: has tissue around seed)
Angiosperms
• 2 Types: Dicots & Monocots
Life Span
• Three Categories:
– Annual: flowering plants that complete life
cycle in one growing season
– Biennial: complete their life cycle in two
years
– Perrenial: flowering plants that live more
than 2 years