FROM ALGAE TO TERRESTRIAL PLANTS

ALGAE Kingdom Protista (some argue Kingdom Plantae) Photosynthetic Unicellular or Multicellular - Unicellular = Diatoms, Dinoflagellates, Euglenoids - Multicellular = Seaweed (Brown, Red or Green) Plants evolved from Algae (linked by green algae)

BROWN ALGAE PHYLUM PHAEOPHYTA -Largest and most complex protists -No true leaves or roots -Contain specialized tissues -Holdfast: structure anchoring algae to rock or other hard structure -Stipe: stem-like structure -Blades: leaf-like structure

BROWN ALGAE PHYLUM PHAEOPHYTA -Ex: Kelp, rockweed

RED ALGAE PHYLUM RHODOPHYTA -Appear to be the first multicellular organisms on earth ( billion years ago) -Most abundant large algae in warm tropical oceans -Contain pigment chlorophyll (green) -Contain pigment phycoerythrin (red) -Allows red algae to thrive in large depths

RED ALGAE PHYLUM RHODOPHYTA -Ex: Nori (used to wrap sushi) -Ex: Carrageenan (help ingredients mix)

GREEN ALGAE PHYLUM CHLOROPHYTA -Found in water, attached to tree surfaces and fur of sloths -Structurally diverse -Contain pigment chlorophyll -Cell walls contain cellulose -Store food in the form of starch *** Most plant-like protist ***

GREEN ALGAE PHYLUM CHLOROPHYTA -Ex: Chlamydomonas (unicellular, flagella) -Ex: Volvox (unicellular, flagella, ball-shaped colonies) -Ex: Ulva/Sea Lettuce (2 cells thick, 1 m long)

THE SHIFT TO LAND SIMILARITIES BETWEEN GREEN ALGAE AND PLANTS ** Refer to Page 93 for a phylogenetic tree depicting evolution CHLOROPHYLLa and b CELL WALLMade of cellulose FOOD STORAGEStarch DNASimilar sequences

ADAPTATIONS TO LIFE ON LAND What adaptations are required for the movement from water to land? -Protection from dessication -Transport system for water and dissolved substances -Support for body of plant -Reproduction is difficult Question: How did these adaptations evolve?

ADAPTATIONS TO LIFE ON LAND Question: How did these adaptations evolve? Answer: Plants started small and grew in moist places Water and dissolved substances transferred via osmosis and diffusion

ADAPTATIONS TO LIFE ON LAND DIFFERENCES BETWEEN GREEN ALGAE AND PLANTS GREEN ALGAEPLANTS ENVIRONMENTAquaticTerrestrial REPRODUCTIONSporic Reproduction Embryos VASCULAR TISSUE Not requiredXylem and Phloem SEEDSNo seedsSeeds FLOWERSNo flowersFlowers

VASCULAR TISSUE XYLEM -Carries water and minerals -Dead, tube-shaped cells -Contain lignin (very tough) PHLOEM -Carries larger molecules, including sugar -Live, tube-shaped cells ROOTS -Strong anchor -Absorb and transport water and minerals

VASCULAR TISSUE

SPORIC REPRODUCTION Alternation of Generations -2 Multicellular stages a)Gametophyte: produces haploid gametes by mitosis b)Sporophyte: diploid version formed by fusing of gametes - Produces spores by meiosis which develop into gametophyte

SPORIC REPRODUCTION