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 !