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LEC 01 Plant Evolution & Diversity Overview FIELD BOTANY – Lecture 01 Dr. Donald P. Althoff ANGIOSPERMS SEEDS & FRUITS (not ___________) Algae-to-Plants: Land Conquered • _______ or rootlike structures • Conducting _________ • Stiffening substance __________ • Waxy ___________ • Pores called ____________ mosses ferns conifers Flowering plants ________ ______ _____________ _______________ protista *Algae—plant-like _________ organisms Reproduction on land “key” • Needed to have new method to transport sperm to eggs • Accomplished by having sex cells carried by _____…or ____…or ________ • And, _______ of developing embryos from __________... Evolutionary process…con’t • First, ________ • Followed by _______… • Then, in the most advanced plants, ________________ ALTERNATING GENERATIONS Gametophyte = (n) produces gametes Sporophyte = (2n) production of spores by meiosis Think 4 Major Divisions Bryophyta Pteridophyta Coniferophyta Anthophyta • • • • • ~16,000 species _____ true roots, leaves & stems root equivalent -- RHIZOIDS ____________ plants rely on diffusion or poorly developed conducting tissues to distribute water & nutrients NON-vascular plants Division: Bryophytes LIVERWORTS & MOSSES LIVERWORTS & MOSSES…con’t • most are _______ (2cm) max height • main adaptation to land: _____________ REPRODUCTIVE STRUCTURES archegonia (egg develops) antheridia (sperm formed) LIVERWORTS & MOSSES…con’t • sperm must swim to egg through a ____ ___________ • egg emits a _______________ to aid in location by the sperm • timing of reproduction MUST coincide with _________________…this is very __________ in dry environments • Seedless: Club mosses, horsetails, & ferns • Seed-bearing: Conifers (pines) flowering plants vascular plants VASCULAR PLANTS (3 MAJOR CATEGORIES) Vascular, ___________ bearing plants FERNS & CLUB MOSSES • PTERIDOPHYTA—ferns most successful (~12,000 species) • LYCOPHYTA--club mosses (ground pine) (~1,000 species) • SPENOPHYTA--horsetails (~15 species) FERNS & CLUB MOSSES…con’t • Distribution and dominance-wise, these plant divisions _____ seen better days… • Life cycles, again, tied to moist conditions… ex: dominant plant body for ferns is the sporophyte (frond) Non-flowering, seed bearing plants Plants PINES, GINKGOS, & CYCADS • Pines (~500 species) (Conifers) • Ginkgos (1 species: Ginkgo biloba… can you remember this one?) -- male & female trees -- extinct in wild -- resistant to air pollution • Cycads (~160 species) Conifers = EVERGREENS (Division: Coniferophyta) • Gymnosperm = “____________” in Latin • Pines, spruces, firs, hemlocks, & cypresses • Once more ______________ and dominant on land • Most are extremely well-adapted to _____(cold), ____ conditions…. Conifers…con’t • Dry & cold environment adaptations: a) thin needles with ______ cuticle b) _____ contains “antifreeze” (what gives it a “piney” fragrance) • How do these adaptations help???? Conifers…reproductive cycle • Dominant form: _____ = diploid sporophyte • Male & female cones • Pollen (from male cones) dispersed by wind • Pollen landing on scale of female cone produces pollen tube that burrows into female gametophyte Flowering Seed Plants ANGIOSPERMS • Division: ANTHOPHYTA (“anthro” is Greek for “_______”) • “Angiosperm” is Greek for “________ ___________________” ….angiosperms produce their seeds enclosed within a fruit • Diverse group….corn, oaks, water lilies, cacti, and buttercups Angiosperms…con’t • ~230,000 species • “the” ________ plant division for over 100 million years • 3 major adaptations: a) 1 flowers 2 fruits b) c) 3 broad leaves 1 Flowers • Produced by sporophyte • Males & females generally in same flower • _______ formed in anther (male) • _______ formed in ovary (female) • Fertilization accomplished with pollen tube through the stigma All in! 2 Fruit • Contains the ovary which contains a ______________ • This adaptation greatly enhanced __________.most seeds pass through digestive tracts of animals unharmed. Some attached to fur. Seeds • Important source of food for humans….including prehistoric times a) easy storage (if kept dry) b) source of protein, oils, carbohydrates, & vitamins …same goes for germinating seed 3 Broad Leaves • During favorable conditions…particularly in tropical and temperate zones…_____ ______________ available to collect sunlight for photosynthesis. • Excess production allows for storage…and subsequent dormant period Broad Leaves…liabilities • Broad, ________ leaves are more appealing to herbivores than conifer leaves (needles) • To __________….some have developed defenses: a) thorns, spines, & resins b) chemical compounds that may be toxic or distasteful mosses ferns conifers Flowering plants Flowers Seeds Vascular tissue All multicelluar protista *Algae—plant-like single-cell organisms