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Plant Review
Chapter 7
Practical Science II
Adapting to Life on Land
• Plants are multicellular eukaryotes with a cuticle and cells surrounded by walls
• Plants have chlorophyll for photosynthesis and store food in the form of starch
• Plants probably evolved from filamentous green algae from ancient oceans but today have tissues and organs (roots, stems, leaves)
• First land plants may have been leafless
Adapting to Life on Land
• Adaptations for terrestrial life– Waxy cuticle– Stomata– Development of leaves, roots and stems– Development of spores and seeds– Alternation of generations life cycle
Plant Classification
• 250,000+ organisms in Plant Kingdom
• 2 Major Divisions (Phyla)
• Bryophyta – nonvascular with no transport tissue so remain small to move water/nutrients by diffusion
• Tracheophyta – vascular, transport tissue to move water and nutrients to various organs of the large plant body
Bryophytes
Pioneer Plants
• Bryophytes are often the first plants to get a foothold in a new area
• Rhizoids help break rocks
• Bodies add organic nutrients
• This results in soil for other plants
• This all leads to succession in that area
Tracheophytes
Ferns
• Oldest tracheophytes
• Spore plants (dominant form)
• Still shows alternation of generations
• True roots, leaves, and stem
• Fronds divided into leaflets
• Underground stems (rhizomes) with roots
Gymnosperms
• “naked seed” exposed, not in fruit
• First woody land plants
• Conifers have needle-like leaves and cones with exposed seeds (evergreens)
• Source of lumber and fuel; paper; tar; turpentine; charcoal
• Also includes gingko and cycad
Other Gymnosperms
Gingko tree Cycad
Angiosperms
• Flowering plants (noticeable or not)
• Youngest and largest group of plants
• True plant organs and vascular tissues
• Monocot or Dicot
• Seed plants; seed protected in a fruit– Dry (peas, beans)– Fleshy (apple, orange)
All angiosperms are either monocots (monocotyledonae)
or dicots (dicotyledonae)
But how can you tell?
Monocot – Dicot
Comparison
Which is monocot and which is dicot?
Plant Reproduction
ALL plants rotate through a life cycle – they have a spore forming stage and a seed forming stage.
It is called Alternation of Generations. The spore or the
seed stage may be dominant over the other. You may not even be
able to see one stage.
Plant Reproductive Cycle
Alternation of Generations
Review It !
What kind of plants are we collecting for our project?
The End !