Chapter 28 pt 2 Bio 94 PDF - Green Plants - Pearson

Green Plants  Land plants are monophyletic and successfully colonized land only a single time. Plants have good fossil record; many adaptations that can be traced in fossil record evolved a single time. We will trace the (4) major adaptive radiations. ❖ History of Green...

Green Plants  Land plants are monophyletic and successfully colonized land only a single time. Plants have good fossil record; many adaptations that can be traced in fossil record evolved a single time. We will trace the (4) major adaptive radiations. ❖ History of Green Plants 4 Successive adaptive radiations What are the major trends across these radiations? ↑ independence from water ↑ body size ↑parental contribution to zygote  ❖ Reproduction: Alternation of generations Meiosis: 2N1N Mitosis: 2N2N or 1N1N Figure 28.12 Universal in land plants: Alternation of generations – multicellular haploid phase (gametophyte) alternates with multicellular diploid stage (sporophyte) Gametophyte Gametes Zygote Gametophyte 1N 1N 1N Sporophyte Meiosis  Syngamy Mitosis 1N Sporophyte Meiosis  Which statement about alternation of generations in plants is NOT true? A. The gametophyte produces gametes by mitosis. B. The sporophyte develops into the gametophyte. C. The zygote develops into the sporophyte through mitosis. D. A single spore develops into the gametophyte.  Which statement about alternation of generations in plants is NOT true? A. The gametophyte produces gametes by mitosis. B. The sporophyte develops into the gametophyte. C. The zygote develops into the sporophyte through mitosis. D. A single spore develops into the gametophyte. Spores, not sporophytes, develop into gametophytes.  What is a general difference in plant life cycles and human life cycles related to alternation of generations ? There’s no multicellular haploid phase in humans (animals). ❖ Non-vascular plants Non-vascular plants True or false: Non-vascular plants lack roots and lack structural support to defy gravity. Non-vascular plants True or false: Non-vascular plants lack roots and lack structural support to defy gravity. True. Rhizoids anchor plant but do not absorb water/minerals. Non-vascular plants True or false: Non-vascular plants lack roots and lack structural support to defy gravity. True. Rhizoids anchor plant but do not absorb water/minerals. True or false: Non-vascular plants mostly obtain water by diffusion. True. Non-vascular plants What are implications? Non-vascular plants What are implications?  Small size Often resistant to desiccation, but need water for reproduction Mosses – Bryophyta (12,000 spp) Wide range of habitats (dormancy) Gametophyte-phase dominant Zygote retained on plant  sporophyte Reproduction requires standing water  Mosses Sphagnum (spp.) – component of peat bogs 1 percent of earth’s land areas -- high latitude Peat – semi-decayed organic material with many human uses (heat source, insulation, soil additive, clean up oil spills)  Peat bogs as carbon sinks – decomposition is slow Climate change  ↑ decomposition Tollund man, 2000 years Siberia old (Denmark)  Other plants that live in bogs Carnivory has evolved in 10 different plant lineages…convergent evolution.  Non-vascular plants are usually small, may be sprawling. Imagine a terrestrial world covered in moss-like plants: what are plants competing for? What happened next in history of plants? 400 mya +  Evolution of vascular tissue (also roots, leaves) Extensive coal- forming swamps of seedless vascular plants Lecture 10  Vascular tissue allowed plants to defy gravity & improved water conduction Which stage in Ancestral state in SVP C x evolution of D A B vascular tissue is present in ferns? Figure 28.8 Figure 28.9 Tracheids  The seedless vascular Choose all that apply: plants are typified by which of the following? A. homospory B. heterospory C. gametophyte dominance D. sporophyte dominance E. pollen  The seedless vascular plants are typified by which of the following? A. homospory B. heterospory Seed plants C. gametophyte dominance Bryophytes D. sporophyte dominance E. pollen Seed plants ❖ Seed plants (360 + mya) Seed= embryo + nutrition + seed coat Advantages? Protection; embryo can disperse far away from parent Radiation of gymnosperms starts 300 mya Pangaea forms, dry warm interior climate  Heterospory – 2 types of spores & associated structures (microspore=male; megaspore=female) Spores develop into ________ , which produce _________. Pollen is the male gametophyte.  Pollen – tiny male gametophyte + sporopollenin resistant to desiccation high dispersability  What constraint did the evolution of pollen free plants from? Need for standing water for reproduction How is fertilization typically accomplished in gymnosperms? Pollen transmitted by wind Figure 28.18 Slide 8 Pollen grains disperse via wind Haploid (n) Microspore (n) Diploid (2n) forms pollen grain Pollen grain Cones with (male gametophyte) Four meiotic microsporangia products; one is Megasporangium large and forms Mother the megaspore (n) cell (2n) Three meiotic products die Pollen grain Ovules (contain Ovulate cone megasporangia) Female gametophyte (n) Megaspore divides to Embryo Egg (n) form female gametophyte (n), (2n) which forms eggs by mitosis. Sperm (Only one egg is fertilized and develops.) Mature Pollen grains sporophyte (2n) Developing carry sperm sporophyte Seeds (disperse via wind or animals) Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved  ❖ Gymnosperms = “naked seeds” Five extant phyla Ginkgo Monophyletic Dominant land form during Mesozoic Cycads/ “sago palm” Cupressophytes (Redwood, etc) Gnetophytes (Ephedra) Pinophyta  Gymnosperms (1000 species) “Conifers” = redwoods & pines high abundance in cold & dry places low species diversity tough leaves (needles): thick cuticle, small surface area Resins contain antifreeze Boreal forest Lecture 10 Gymnosperms dominant throughout much of Mesozoic Angiosperms arose in Mesozoic & radiated in Cenozoic Angiosperm adaptive radiation 80% of extant land plants are angiosperms. What three adaptations contributed most to their success? 1. 2. Vessels 3. Flowers Fruits { } coevolution with animals ❖ Angiosperm = “enclosed seed” Reproductive adaptations: – 1) Flower (esp. ovary, contains female gametophyte) and its products – 2) Coevolution with animals Water lily  Angiosperms extend heterospory; further gametophyte stage reduction of __________ Flower (2n) & its products Male: stamen = anther + filament Microspores in anther pollen Petals and sepals = modified leaves Female: carpel Megaspores in ovary  female gametophyte  Angiosperms extend heterospory; further gametophyte stage reduction of __________ Flower (2n) & its products Male: stamen = anther + filament Microspores in anther pollen Petals and sepals = modified leaves Female: carpel Floral displays  Megaspores in ovary  increase pollination female gametophyte success & efficiency  True or false: one function of fruit is to extend seed dormancy. A. True B. False False: Endosperm extends seed dormancy.  True or false: fruit is part of the seed. A. True B. False False. What are two functions of fruit?  True or false: fruit is part of the seed. A. True B. False False. What are two functions of fruit? Seed dispersal Seed protection Is seed dispersal always performed by animals? ❖ Plant- Animal Coevolution ✓ Review: Species are agents of selection when they interact. Coevolution – (def.) 2 interacting species influence each other’s adaptations on a sustained basis Mutualistic vs antagonistic (1)Mutualistic coevolution – Angiosperms and their pollinators  Pollination syndrome – close correlation between structure of flower and size, shape, & behavior of its pollinators (2) - Antagonistic coevolution (“arms race” ) (def.) – Evolution of adaptations and counter- adaptations between competing species or between predators and their prey. Why is the world green? Plant defenses against herbivory Mechanical Calcium oxylate crystals Plant defenses against herbivory Chemical Eg, alkaloids, amines, diterpenoids, saponins, carenolides, phenols, curcubitacins, canogenic glycosides Plant defenses against herbivory Chemical Eg, alkaloids, amines, diterpenoids, saponins, cardenolides, phenols, curcubitacins, canogenic glycosides One organism’s toxin is another’s medicine…  Arms Race: Milkweeds & Longhorn Beetles Milkweeds (Asclepias) Each species produces a distinct cardenolide. Longhorn beetles live on milkweed. Beetles immune to the toxin found on species they eat. Aposematism  Each beetle specializes on one host plant species. Coevolution between Asclepias and Tetraopes: host plants “escape” by beetles host plants mutation, but beetle catches up. 10 –13 co-speciation events over 40 my. ❑ Coevolution increases number of species.  Principle of allocation: Organisms have finite resources, which must be allocated strategically to maximize fitness. Trade-offs are inevitable. Inducible defense – physical, chemical, behavioral trait that is induced in the “prey” by the presence of the predator/consumer. Constitutive defense – a defense present in a prey species even in the absence of a predator/consumer.  Are the defenses described in the water lily video constitutive or inducible? How would we know?  ❖ Uses of plants What are ecosystem services provided by plants? Soil composition, water retention, primary production, O2 production, carbon cycle What are human uses of plants?  Key lineages Know general traits of each level of organization (non-vascular plants, seedless vascular plants, seed plants,and differences between angiosperms vs gymnosperms) Know specific traits of mosses, ferns, pinophytes/cupressophytes Know general patterns of coevolution between angiosperms and other groups About 25% of atmospheric carbon increase due to loss of forests ❖ Summary Green Plants = green algae + land plants Colonization of land: adaptations for ↑ size, ↑independence from standing water, ↑ nutrition to offspring -- most adaptations evolved once Provide critical ecosystem services and human needs  ❖ Summary Two types of coevolution: mutualistic and antagonistic Mesozoic: Angiosperm/insect coevolution began Cenozoic: coevolutionary radiation escalated Plants Vocabulary Vocabulary (continued) Objectives Trace the evolution of plants on land and explain how evolutionary innovations contributed to the success of each taxon. Understand the conditions on Earth that contributed to the success of successive plant lineages. Identify the major patterns of land plant reproduction. Compare and contrast traits of bryophytes, ferns, gymnosperms and angiosperms. Define and use appropriate plant reproductive terminology. Identify two types of coevolutionary dynamics and their consequences for diversity. Apply the Principle of Allocation and the concept of trade-off to organismal design and function. Figure 28.23  Think about whether these services are of value you to you. Think about it when you decide you want a career helping other people. Think about it when your vote.  Sporophyte-dominated life cycle (Homospory – one type of spore) Gametophyte much reduced  Coevolution  speciation and increased diversity Shyamal (& Tiffney) 2007 Which of the following is a difference between a fern and a conifer? A. A fern lacks vascular tissue, while a conifer possesses vascular tissue. B. The sporophyte of fern is not photosynthetic, while the sporophyte of a conifer is photosynthetic. C. The fern life cycle is gametophyte-dominant, while that of a conifer is sporophyte-dominant. D. A fern is heterosporous, while a conifer is homosporous. E. A fern produces a photosynthetic gametophyte, while a conifer does not. CQ -- What is/are evolutionary advantage(s) found in the angiosperm lineage? A. Increased likelihood of successful pollination B. Flowers produced at little expense C. Increased dispersal of seeds D. Increased tolerance for hot and dry conditions E. A and C  Land plants: Match term to picture and estimate when each lineage evolved. A bryophyte  angiosperm B gymnosperm fern C D  Land plants: Match term to picture and estimate when each lineage evolved. A bryophyte C angiosperm B gymnosperm fern C D  Land plants: Match term to picture and estimate when each lineage evolved. A bryophyte C angiosperm D B gymnosperm fern C D  Land plants: Match term to picture and estimate when each lineage evolved. A Bryophyte C angiosperm D B gymnosperm B fern C D  Land plants: Match term to picture and estimate when each lineage evolved. A bryophyte C  angiosperm D B gymnosperm B fern A C D  Land plants: Match term to picture and estimate when each lineage evolved. A bryophyte C  angiosperm D B gymnosperm B fern A C D Is the dominant generation haploid or diploid? Bryophyte; n Fern; 2n Gymnosperm; 2n Angiosperm; 2n What is the general size trend over time? Gametophyte  smaller; Sporophyte  larger