CHAPTER 1 BIODIVERSITY 1
Learning outcomes : 1.6 Domain Eukarya: Kingdom Plantae (a) Describe alternation of generation as the unique characteristics of Plantae (b) State the classification of Plantae into four groups : i. Bryophytes ii. Pteridophytes iii. Gymnosperms iv. Angiosperms 2
http://www.fao.org/state-of-forests/ 3
• Multicellular eukaryotes • Photosynthetic autotrophs that utilize chlorophylls to trap light energy for the process of photosynthesis • Primary food storage : starch • Cell wall : cellulose • Have 2 generations : Alternation of generations UNIQUE CHARATERISTICS Learning Outcomes : 1.6 (a) Describe alternation of generation as the unique characteristics of Plantae. 4
• “A life cycle in plants involved the alternation between 2 generations of distinct multicellular stage: sporophyte (diploid/2n) and gametophyte (haploid/n) generation” • In which takes turn to produce one another during the life cycle. ALTERNATION OF GENERATION Learning Outcomes : 1.6 (a) Describe alternation of generation as the unique characteristics of Plantae. solomon, 2018 5
• Sporophyte generation which produce haploid spores by meiosis • Gametophyte generation which produce haploid gametes by mitosis ALTERNATION OF GENERATION Learning Outcomes : 1.6 (a) Describe alternation of generation as the unique characteristics of Plantae. solomon, 2018 6
• Starts with a mature sporophyte (2n) which produces haploid spores by meiosis, a process which results in a reduction of the number of chromosomes by a half • The spores germinate and grow into a gametophyte(n) ALTERNATION OF GENERATION Learning Outcomes : 1.6 (a) Describe alternation of generation as the unique characteristics of Plantae. solomon, 2018 7
• At maturity, the gametophyte(n) produces gametes by mitosis, which does not alter the number of chromosomes • Two gametes fuse to produce a zygote, which develops into a diploid sporophyte (2n) ALTERNATION OF GENERATION Learning Outcomes : 1.6 (a) Describe alternation of generation as the unique characteristics of Plantae. solomon, 2018 8
Classification of Plantae : 4 Groups Bryophytes Pteridophytes Gymnosperms Angiosperms Learning Outcomes : 1.6 (b) State the classification of Plantae into four groups. 9
Learning Outcomes : 1.6 (b) State the classification of Plantae into four groups. 10
Learning outcomes : 1.6.1 Bryophytes (a) Describe the unique characteristics of Bryophytes (b) State the classification of Bryophytes into three (3) divisions / phyla : i. Phylum Hepatophyta (Marchantia sp.) ii. Phylum Bryophyta (Polytrichum sp.) iii. Phylum Anthocerophyta (Anthoceros sp.) (c) State the terrestrial adaptation for bryophytes. 11
1.6.1 Bryophytes https://en.wikipedia.org/wiki/Bryophyte http://www.natperspective.com/nature/authors.html 12
UNIQUE CHARACTERISTICS • Most primitive terrestrial plants • Habitat : damp, shady places (highland area) • Non-vascular plants • No true stems, leaves & root • Have rhizoids (attach to the soil) • Gametophyte generation is dominant Learning Outcomes : 1.6.1(a) Describe the unique characteristics of Bryophytes 13
• Gametes develop within gametangia. • Male gametangium: antheridium produces antherozoid • Female gametangium: archegonium produces oosphere • Sporophytes are smaller & shorter lived and depend on the gametophytes for the water and nutrients. Phylum Hepatophyta Learning Outcomes : 1.6.1(a) Describe the unique characteristics of Bryophytes 14
3 phyla : i) Phylum Hepatophyta (eg: Marchantia sp.) ii)Phylum Bryophyta (eg: Polytrichum sp.) iii)Phylum Anthocerophyta (eg: Anthoceros sp.) Learning Outcomes : 1.6.1(b) State the classification of Bryophytes into three (3) divisions / phyla; 15
i) Phylum Hepatophyta (eg: Marchantia sp.) Learning Outcomes : 1.6.1(b) State the classification of Bryophytes into three (3) divisions / phyla; 16
LECTURE Learning Outcomes : 1.6.1(b) State the classification of Bryophytes into three (3) divisions / phyla; i) Phylum Hepatophyta e.g. Marchantia sp.(Liverworts) 17
LECTURE Learning Outcomes : 1.6.1(b) State the classification of Bryophytes into three (3) divisions / phyla; ii) Phylum Bryophyta e.g. Polytrichum sp. https://istudy.pk/polytrichum/ 18
iii) Phylum Anthocerophyta e.g Anthoceros sp. (Hornworts) LECTURE Learning Outcomes : 1.6.1(b) State the classification of Bryophytes into three (3) divisions / phyla; 19
TERRESTRIAL ADAPTATIONS FOR BRYOPHYTES Learning Outcomes : 1.6.1(c) State the terrestrial adaptation for bryophytes. 1) Water conservation by waxy cuticle - In some bryophytes, epidermis of leaves and other aerial parts is coated with cuticle to prevent excessive loss of water by evaporation - Thus, preventing the bryophytes from being desiccated (drying out) 20
TERRESTRIAL ADAPTATIONS FOR BRYOPHYTES Learning Outcomes : 1.6.1(c) State the terrestrial adaptation for bryophytes. 2) Presence of multicellular gametangium -Gametes are produced within gametangia. -Gametangia has a layer of sterile (nonreproductive) cells that surrounds and protects the gametes -Diploid zygote develops into embryo within the female gametangium to protect embryo during its development. https://slideplayer.com/slide/4621614/ 21
TERRESTRIAL ADAPTATIONS FOR BRYOPHYTES Learning Outcomes : 1.6.1(c) State the terrestrial adaptation for bryophytes. 3)Multicellular, dependent embryo - Diploid zygote develops into diploid embryo by mitosis within the archegonium - Gametophyte carry out photosynthesis and provide developing embryo with nutrients and water ttps://status.libretexts.org. 22
TERRESTRIAL ADAPTATIONS FOR BRYOPHYTES Learning Outcomes : 1.6.1(c) State the terrestrial adaptation for bryophytes. 4) Walled spores produced in sporangium Walls of haploid spores contain sporopollenin (exine) - make the walls tough and resistant to harsh environments - enable the wind-carried spores to disperse through air without being desiccated -The outer tissues of sporangium protect spores until they are released into air https://status.libretexts.org. 23
Learning Outcomes : 1.6.2 Pteridophytes (a) Describe the unique characteristics of Pteridophytes (b) State the classification of Pteridophytes into two divisions / phyla: i. Lycophyta (Lycopodium sp., Selaginella sp.) ii. Pterophyta (Dryopteris sp.) 24
UNIQUE CHARACTERISTICS • Seedless vascular plants. • Have true roots, stem (rhizome) & leaves (frond) • True roots with lignified vascular tissue. - xylem : tracheid only - phloem : sieve tube only • Larger size than Bryophytes Learning Outcomes : 1.6.2(a) Describe the unique characteristics of Pteridophytes https://www.ck12.org/c/biology/fern/ lesson/Ferns-Advanced-BIO-ADV/ 25
• Distinct alternation of generation - sporophyte (2n) generation is dominant • Habitat : found in place of low light intensity in the tropical & subtropical regions • Reproductive system : still dependent on water for fertilization • Ferns reproduce sexually by producing spores Learning Outcomes : 1.6.2(a) Describe the unique characteristics of Pteridophytes https://www.biologypages.info/F/Ferns.html 26
Classification of Pteridophytes ii) Phylum Pterophyta e.g.Dryopteris sp. 2 phyla : i) Phylum Lycophyta Learning Outcomes : 1.6.2 (b) State the classification of Pteridophytes into two divisions / phyla: e.g. Lycopodium sp. e.g. Sellaginella sp. https://alchetron.com/Lycopodium https://www.wordnik.com/words/Selaginella http://www.sharnoffphotos.com/nature/wild_plant s/wild_plantsDF/dryopteris_sp.html 27
Learning Outcomes : 1.6.4Gymnosperms (a) Describe the unique characteristics of Gymnosperms (b) State the classification of Gymnosperms into four (4)divisions (phyla) : i. Phylum Cycadophyta (Cycas sp.) ii. Phylum Pinophyta / Coniferophyta (Pinus sp.) iii. Phylum Ginkgophyta (Ginkgo sp.) iv. Phylum Gnetophyta (Gnetum sp.) 28
• Seed is not enclosed within ovary • Reproductive organ : cone consist of the sporophylls that are spirally arranged. • Sporophyte is dominant • Leaves with a waxy coating : To help conserve water Learning Outcomes : 1.6.4(a) Describe the unique characteristics of Gymnosperms UNIQUE CHARACTERISTICS http://emhsbotzoo.wikispaces.com/file/view/Pine_cones.png/60043070 29
• Ovules contain the female gametophyte • Water is not required during fertilization • vascular tissue – Xylem : tracheid – Phloem : sieve tube *except for Gnetophyta Learning Outcomes : 1.6.4(a) Describe the unique characteristics of Gymnosperms 30
Classification of Gymnosperms i) Phylum Cycadophyta (eg: Cycas sp.) ii) Phylum Pinophyta/Coniferophyta (eg: Pinus sp.) iii) Phylum Ginkgophyta (eg: Ginkgo sp.) iv) Phylum Gnetophyta (eg: Gnetum sp.) Learning Outcomes : 1.6.4(b) State the Classification of Gymnosperms into four divisions 31
i) Phylum Cycadophyta : Cycas sp. Learning Outcomes : 1.6.4(b) State the Classification of Gymnosperms into four divisions - Dioecious - they have compound leaves that look somewhat like palms https://en.wikipedia.org/wiki/Cycas_rumphii A female (left) and male cycad. Photograph: Courtesy of Ventnor Botanic Garden 32
STAMINATE CONES OVULATE CONES ii) Phylum Pinophyta / Coniferophyta : Pinus sp. Learning Outcomes : 1.6.4(b) State the Classification of Gymnosperms into four divisions Woody plants, have needle or scale-like leaves Monoecius (both male & female cones in the same plant) Heterosporous: megaspore → female gametophyte microspore → male gametophyte 33
iii) Phylum Ginkgophyta : Ginkgo sp. e.g. Ginkgo biloba Learning Outcomes : 1.6.4(b) State the Classification of Gymnosperms into four divisions https://www.ornamentaltrees.co.uk/ginkgo-biloba-tree-p384 https://www.verywellmind.com/ginkgo-biloba-for-anxiety-89334 34
iv) Phylum Gnetophyta : Gnetum sp. e.g. Gnetum gnemon Learning Outcomes : 1.6.4(b) State the Classification of Gymnosperms into four divisions LECTURE https://www.pinterest.com/pin/521010250623999646/ 35
Learning Outcomes : 1.6.5 Angiosperms (a) Describe the unique characteristics of Angiosperms (Phylum Anthophyta) 36
• have flowers as reproductive organ • seed is enclosed within ovary • Have complex vascular tissues - xylem consists of tracheids & vessels - phloem consists of sieve tubes & companion cells Learning Outcomes : 1.6.5(a) Describe the unique characteristics of Angiosperms UNIQUE CHARACTERISTICS 37
• Sporophyte is dominant • Double fertilization occurs producing the nutritive triploid endosperm • Fruits are formed which serves as protection and means of dispersal for the seeds Learning Outcomes : 1.6.5(a) Describe the unique characteristics of Angiosperms 38
Learning Outcomes : 1.6.5(a) Describe the unique characteristics of Angiosperms https://en.wikipedia.org/wiki/Mangifera_indica https://plantstomata.wordpress.com/2016/11/27/stomatal-structures-in-zea-mays-monocots/ 39
Differences between Dicotyledonae and Monocotyledonae Learning Outcomes : 1.6.5(a) Describe the unique characteristics of Angiosperms 40