UNIT 6: BRYOPHYTES

Study Questions  Lecture Outline
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KEY WORDS

Bryophytes Foot Gemmae
Thallose Seta Venter
Hygroscopic Capsule Paraphyses
Hydroids Elaters Anthoceros
Leptoids Calyptera Protonema
Doctrine of Signatures Operculum  
Marchantia Peristome  
Antheridia Sphagnum  
Archegonia Protonema  


STUDY QUESTIONS

UNIT 6: BRYOPHYTES
1 - Common ancestors from which the Bryophytes most probably evolved

2 - Primary photosynthetic pigment in the Bryophytes

3 - Water conducting cells in mosses

4 - Dominant generation in mosses

5 - Root-like structures produced by liverworts

6 - Dominant generation in liverworts

7 - A liverwort genus

8 - Cell division process which produces liverwort spores

9 - Specialized spore threads with spirally thickened walls

10 - Structures involved in asexual reproduction of liverworts

11 - Generation of the horn-shaped structure in the hornworts

12 - Dominant hornwort generation

13 - Moss structure formed by a germinating spore

14 - Leafy moss generation

15 - A moss genus

16 - Lid of the moss capsule

17 - Generation of the moss calyptra

18 - Moss structure which regulates spore discharge

20 - Primary influence of peat moss which is added to soil


LECTURE OUTLINE

UNIT 6: BRYOPHYTES

Bryophytes - transition to land
   1 - Characteristics
       a - lack true leaves, stems, roots - form rhizoids for absorption
       b - lack organized conducting tissue, cells: hydroids (water),
           leptoids (food)
       c - heteromorphic generations, oogamous, gametophyte is dominant
       d - sex organs: multicellular embryo in archegonium
       e - fertilization requires water
   2 - Groups
       a - liverworts: example - Marchantia, thallose
           life cycle: 1N plant body, sexual: antheridia + oogonia
           -> fertilization -> sporophyte: foot, seta, capsule
           meiosis forms spores with elaters
	     -asexual reproduction by gemmae
       b - hornworts: example - Anthoceros 
	     2N (sporophyte) is upright, elongate, green
           Plant body haploid (dominant gametophyte)
       c - mosses
           (1) characteristics - soil pioneers. Acid soil, retard
               erosion, drought resistant, sensitive to environmental 
               pollution
           (2) life cycle
               haploid spores -> protonema -> leafy gametophyte -> archegonia,
               antheridia, paraphyses -> fertilization -> sporophyte -> meiosis 
		    forms spores
	       sporophyte structures: foot, seta, capsule: calyptra (1N -actually 
		    gametophytic tissue), operculum, peristome
	     (3) example: Sphagnum (peat) swamp, water holding capacity


TABLE UNIT 6 GEOLOGIC TIME SCALE ______________________________________________________________________________ MILLION EARLIEST YEARS EVIDENCE BEFORE ERA PERIOD AGE OF PLANTS PRESENT ______________________________________________________________________________ CENOZOIC AGE OF MODERN SEED _________________________ PLANTS _____GRASSES ______________________130 MESOZOIC FLOWERING PLANTS AGE OF ________________________ ANCIENT SEED ______________________________________ PLANTS PALEOZOIC GINKGO CONIFERS _____________________________________________________________________________ CARBONIFEROUS ________________ FERNS _____________________ AGE OF _________________________________350 SPORE-BEARING LYCOPODS DEVONIAN PLANTS HORSETAILS BRYOPHYTES ______________________________________________________________________400 _____________________ AGE OF CAMBRIAN BACTERIA _________________________________500 _____________________ AND ALGAE MARINE PRECAMBRIAN ALGAE ______________________________________________________________________________

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