plants chapter 29 ap biology: overview. key concepts: zthe plant kingdom consists mostly of...
TRANSCRIPT
Plantschapter 29
APBiology: overview
Key Concepts:
The plant kingdom consists mostly of multicelled photoautotrophs
Almost all plants live on land
Plants have structural adaptations that allow them to photosynthesize, absorb water and ions, and conserve water
Land plants are reproductively adapted to withstand dry periods
Key Concepts:
Seed producers were more successful in radiating into drier environments based on an evolutionary scale
Gymnosperms and angiosperms are vascular plants
Angiosperms include two classes of flowering plants Dicots and Monocots
Evolutionary Trends Among Plants
Photoautotrophs
Vascular plants Roots, stems,
leaves
Gymnosperms
Seed bearing
Gingko
Cycads
Conifers
Angiosperms Flowers and seeds
Dicots and Monocots
Non-vascular plants Bryophytes
Liverworts
Hornworts
Mosses
Evolution of Roots, Stems, and Leaves
Roots and Stems Below ground
Shoot systems Stems and leaves
Above Ground
Sunlight and CO2
Support of cell wall
Lignin
Vascular tissue Xylem
Phloem
Water conservation Cuticle
Stomata
Evolutionary Trend Among Plants
Alternation of generations
Evolution of Pollen and Seeds
HomosporyHeterospory
Pollen grainsSperm-bearing gametophytesFemale gametophytes
Spread by air, insects, birds
Seeds Embryo of gametophytes Nutritive tissues Protective coat
Bryophytes
Mosses
Liverworts
Hornworts Nonvascular
Moist habitats mostly
Small
< 20 cm tall
Simplest plants
Bryophytes
Moss Life Cycle
Moss Life Cycle
Existing Seedless Vascular Plants
Whisk ferns, Lycophytes, Horsetails, Ferns 3 Differences from Bryophytes
Sporophyte not attached to a gametophyte
Has vascular tissuesLonger phase in life cycle
Habitat Moist places
Gametophytes lack vascular tissueSperm needs water to reach egg
Life Cycle of a Fern
Life Cycle of a Fern
The Rise of the Seed-Bearing Plants
Seed ferns, gymnosperms, angiosperms Pollen grains
Male gametophytes
Ovules
Egg producing gametophytes
Pollination
Pollen grains arrive on female reproductive structures
Independent of water for fertilization
Note the decrease in size of Gametophyte generation
Important Adaptations for land plants
Vascular tissue transports water and Vascular tissue transports water and nutrients to the body of the plantnutrients to the body of the plant
Cuticle provides an effective barrier to Cuticle provides an effective barrier to water losswater loss
Stomata bordered by guard cells that Stomata bordered by guard cells that regulate opening, and thus water lossregulate opening, and thus water loss
Ferns
Spore of A Lycophyte
Seed-Bearing Plants
Depend on
Pollen grains
Ovules that mature into seeds
Tissue changes adapted to dry conditions
Gymnosperms- Plants with “Naked” Seeds
Conifers, Cycads, Ginkgos, Gnetophytes Conifers - cones
Pines, cypress, firs, spruces, redwoods
Lesser Known Gymnosperms
Cycads Tropical
Subtropical areas Largest seed-
bearing cones Zamia in Florida
Gingko Gingko biloba Diverse in
dinosaur times
Gnetophytes Gneton
Tropics
Ephedra
California
Welwitschia mirabilis
Deserts in Africa
Pines
AngiospermsThe Flowering Seed-Bearing Plants
Flowers
Coevolution with pollinators Insects
Bats Birds
Seed
Ovary
Dicots and Monocots
Almost 180,000 Dicots are herbaceous Cabbage and Daisies
Flowering shrubs and trees
Water lilies
Cacti
About 80,000 Monocots Orchids, palms, grasses, crop plants, rice
In Conclusion
Plants probably arose from green algae
Trends in evolution can be identified by comparing structural adaptations to dry conditions, shifts to diploid dominance, and the shift to heterospory
Bryophytes are nonvascular plants and require free water for fertilization
Vascular plants are adapted to life on land
In Conclusion
Gymnosperms are vascular plants that produce pollen grains and seeds
Ovules contain the egg-producing female gametophytes
Evolution of pollen grains freed these plants from dependence on water for fertilization
Angiosperms produce flowers and coevolved with pollinators