* For more than 3 billion years of Earth´s history, the land surface was largely lifeless.
* Ordovician: first land plants
* Silurian: earliest vascular plants
* Devonian Period: The greening of land.
THE CLOSEST TO A PLANTAE
* In eubacterias : Prochloron spp. → Chlorophyll a & b with the carotenoid accesory pigments
* In algaes: Charophytaspp. → have chlorophyll a & b with the carotenoid accesory pigments. Starch as a storage product. The closest to plantae in algaes.
* In protista: Chara and Coleochaete.
Plants → Chlorophyll a & b with the carotenoid accesory pigments. Starch as a storage product. Cellulose in CW
* The green algal ancestors of the PK made their first successful attemptsto invade land 435 mya. Origin of Rhyniophytes (earliest vascular plants) in the Silurian.
* It took 60 my or so for plants to radiate into diverse land habitats; through long-term changes in structure, function, and modes of reproduction.
* Roots : Simple underground structures started to form when plants colonized the land and eventually developed into ROOTS.
*Aboveground shoots developed, stems and leaves came later. Eventually plants started to synthesize lignin in cell walls → wood
LIFE ON LAND
* From Haploid (dominant in algae) to Diploid (dominant in Plants)
* From depending on water to water independent life cycles.
* Seed-bearing plants produce 2 types of spores → heterospory as oposed to homospory (one type of spore)
* Macrospores →ovules Microspores → are the start of pollen grains (cellular structures that become mature, sperm-bearing male gametophytes)
* Can withstand dry environmental conditions
* Each seed has a protected embryo
* Peat Bogs(turberas)
* Dead bodies up to 2 000 or 3 000 years old have been found in acidic peat bogs. Maybe ancient people used these places for human sacrifices.* Cerro de la Muerte
* Seedless plants arose about 360 mya as the Devonian gave way to the Carboniferous.
* They would become the most successful group of the PK.
* Seed ferns (now extinct), Gymnosperms and later Angiosperms.
* Seed plants produce→ pollen grains (sperm-bearing male gametophytes)
* Microspores: give rise topollen grains
* Megaspores : develop within the ovules, each ovule consists of a female gametophyte (with egg cell), nutrient-rich tissue, and a jacket of cell layers that develop into seed-coat.
* Carboniferous : seed-ferns (extinct today)
* By the end of this period Gymnosperms make their appearance.
* Permian : most of the typical vegetation of the Carboniferous becomesextinct; gymnosperms become dominant.
* Mesozoic : Gymnosperms dominant; by the end Angiosperms make their appearance
* Delivers the sperm to the ovule, even in prolonged periods of drought (no need of H2O for the sperm to swim to the female gametophyte).
* Pollen can be transported by wind or by insects, birds, mammals, and other animals that carry them to eggs.* Pollination → the arrival of pollen grains on the female reproductive structure.
NON VASCULAR PLANTS
* They do not have vascular tissue.
* Never envolver into large plants.
* Envolved during the Devonian Period, after the vascular plants.
* Origin Early Devonian.
* Dependent on water for reproduction.
* Very tiny, less than 20cm.* During WWII Sphagnum spp was used as a bendage. The acids of this organism secretes, hamper the growth of bacteria and fungus.
* Examples: moses, liverworts, and hornworts.
* Internal tissue systems that conduct water and solutes through roots, stems, and leaves.
a. Cambium: produces new xylem and phloem (tissues that contribute to widening)...