1. PLANT EVOLUTION Evolutionary Trends Bryophytes
The rise of the vascular plants
The rise of the seed plants

2. Kingdom Plantae General features:
Eukaryotic, multicellular, photosynthetic autotrophic organisms
P.S.= H2O + CO2+ sunlight  oxygen + sugar
C.R. = sugar + O2  CO2 and H2O + NRG
Origins = blue-green bacteria  ancestral green algae  algae bryophytes  tracheophytes

3. The Phyla Phyla grouped into:
- Nonvascular plants (lack true (lignified) vascular tissue)
- Seedless vascular plants (true vascular tissue (phloem and xylem), but reproduce only by spores (no seeds made)
- Seed bearing vascular plants

4. Ferns

5. Cone Bearing Plant

6. Flowering plant

7. Setting the Stage Earth’s atmosphere was originally oxygen free
Ultraviolet radiation bombarded the surface
Photosynthetic cells produced oxygen and allowed formation of protective ozone layer

8. Pioneers in a New World
Cyanobacteria were probably first to produce oxygen
Later, green algae evolved and gave rise to plants

9. Advantages and Disadvantages of life on land
Sunlight unfiltered by water and plankton
Atmosphere had more CO2 than water
Soil was rich in mineral nutrients
Originally relatively few herbivores and pathogens
Relative scarcity of water
Lack of structural support against gravity

12. Evolutionary trends in plants structure:
Plants came from the sea which support, keep temp constant, bath whole plant with nutrients
Adaptations to terrestrial Life =
Roots to anchor and absorb
Conducting vessels xylem & phloem to carry nutrients up and glucose around VASCULAR TISSUE
Stiffening ligin to support the plant
Waxy cuticle on leaves and stem to prevent evaporation
Stomata pores in leaves to allow gas exchange, but close to prevent water loss

13. Evolutionary Trends in reproduction:
Algae reproduce in water so gametes are carries by water, form zygotes in water and disperse in water. Ie No protection from dehydration required
Land plants needed:
Transport gametes (pollen, flowers)
Protection from drying out (seeds)
Dispersal (seed coats & fruits)

14. Evolutionary Trends in Plant life cycles:
Alternation of Generations = haploid gametophytes produces sex cells by mitosis. Gametes unite to from a diploid zygote, which develops into diploid sporophyte that develops haploid spores by meiosis

15. Haploid to Diploid Gametophyte Sporophyte Spore
Haploid gamete producing body
Sporophyte
Diploid product of fused gametes
Spore
Resting structure
The most recently evolved groups produce seeds and pollen grains which were the key innovations that allowed the seed plants to spread widely into diverse habitats.

17. Evolutionary Trend Relative size Life span zygote SPOROPHYTE (2n)
GAMETOPHYTE (n)
Relative size
Life span
GREEN ALGAE
BRYOPHYTE
FERN
GYMNOSPERM
ANGIOSPERM

18. General Trend = decreased size, duration, and prominence of gametophyte generation relative to sporophyte
Algae = some have no sporophyte or only the zygote
Mosses = gametophyte is green leafy and sporophyte is small and short lived
Ferns = sporophyte is the fronds of the ferns, gametophyte is smaller yet independent
Seeded plants = male and female gametophytes are microscopic and produce gametes to form sporophyte embryo
Recall: evolution occurs because of advantageous traits being selected therefore what is the advantage of diploid sporophyte dominance?

20. Sporophyte
The generation in the life cycle of a plant that produces spores.
Is diploid but its spores are haploid.
Either completely or partially dependent on the gametophyte generation in mosses and liverworts, but is the dominant plant in the life cycle of clubmosses, horsetails, ferns and seed plants.

21. LE 29-9d
Polytrichum
commune,
hairy cap
moss
Sporophyte
Gametophyte