* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Diagrams to Review C26
Survey
Document related concepts
Plant physiology wikipedia , lookup
Plant ecology wikipedia , lookup
Plant nutrition wikipedia , lookup
Plant morphology wikipedia , lookup
Perovskia atriplicifolia wikipedia , lookup
Plant use of endophytic fungi in defense wikipedia , lookup
Plant evolutionary developmental biology wikipedia , lookup
Evolutionary history of plants wikipedia , lookup
Ficus macrophylla wikipedia , lookup
Plant reproduction wikipedia , lookup
Transcript
.475 .7 1.7 2 3.5 3.8 4 P 494 Ancient Reducing Atmosphere • Oparin and Haldane proposed that Earth’s ancient atmosphere was reducing rather than oxidizing. • Why was there no free oxygen in Earth’s early atmosphere? • Why would the first life not evolve in an oxidizing atmosphere? Miller and Urey simulated Earth’s early atmosphere electricity simulated lightning Why did they use uV light? An alternate atmosphere contained carbon monoxide, carbon dioxide, nitrogen gas and water vapor Experiments have produce all 20 amino acids, sugars, lipids, purines, pyrimidines What is the importance of amino acids? What is the importance of nucleic acids? Formerly eubacteria Archaea live in extreme environments and have cell walls with no peptidoglycan Most bacteria range from 15 um while eukaryotes range from 10100 um Simple cell wall with relatively large amounts of peptidoglycan Penicillin prevents crosslinking in the peptidoglycan and prevents the formation of a functional cell wall More complex cell wall with less peptidoglycan but with an outer membrane with lipopolysaccharides -carbohydrates bonded to lipids Pseudomonas Rhizobia Nitrosomonas Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings • Under one evolutionary scenario, the endomembrane system of eukaryotes (nuclear envelope, endoplasmic reticulum, Golgi apparatus, and related structures) may have evolved from infoldings of plasma membrane. • Another process, called endosymbiosis, probably led to mitochondria, plastids, and perhaps other eukaryotic features. Fig. 28.4 Formation of Chloroplast cyanobacteria green algae green plants Problems Aquatic Plants Face in a Terrestrial Environment • Obtaining enough water • transporting water and dissolved substances from restricted areas of intake to other areas • Preventing desiccation • Maintaining enough moist surface area for gas exchange • carry out reproduction in an environment where sperm, zygote and embryo will dry out • withstanding extreme fluctuations in environment • Supporting a large plant body against gravity Four Major Groups Adaptations of Bryophytes • form embryophytes • Gametes develop within gametangia – anthridium – archegonium • Spores with walls of sporopollenin • cuticle • stomata • alternation of generations – the haploid gametophyte is the dominant generation • Bryophytes, pteridiophytes, gymnosperms, ands angiosperms demonstrate four great episodes in the evolution of land plants: 1. the origin of bryophytes from algal ancestors 2. the origin of vascular plants and their diversification 3. the origin of seeds 4. the evolution of flowers Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 29.1 Homologies between Charophytes and Plants • Homologous chloroplasts – chlorophyll b, betacarotene – thylakoids as grana – DNA • Biochemical similarity – cellulose cell walls (rosette cellulosesynthesizing complexes) – matching enzymes within peroxisomes • Similar mitosis and cytokinesis – dissapearance of nuclear envelope – spindle remains till cytokinesis – Cell plate formation • similar sperm • similar genes and rRNA • The elongation and branching of the shoots and roots maximize their exposure to environmental resources. • This growth is sustained by apical meristems, localized regions of cell division at the tips of shoots and roots. – Cells produced by meristems differentiate into various tissues, including surface epidermis and internal tissues. Fig. 29.3 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings •In pteridophytes, gymnosperms, and angiosperms, the The gametophyte is bisexual producing sporophyte Most ferns areis the dominant generation. homosporous both sperm and eggs •For example, the fern plant that we typically see is the diploid sporophyte, while the gametophyte is a tiny plant on the forest floor. The cuticle is a secondary product produced on the surface of leaves to prevent dessication Xylem Phloem The stomata is an adaptation to let in carbon dioxide into the leaf Adaptations to Terrestrial Life • • • • • • Stomata p582 Cuticle p581 lignin Sporopollenin p580 gametangia p581 embryophytes • vascular tissue p582 • seeds • flowers Adaptation of Vascular Plants • Root systems – absorbs water and minerals • Aerial shoot systems and leaves – for photosynthesis • Conducting tissue – xylem and phloem • Lignin – to strengthen and support cellulose cell walls • Sporophyte is the dominant stage • Branching in Sporangia – increases the # of spores Most ferns are homosporous The gametophyte is bisexual producing both sperm and eggs Microscopic gametophytes of seed plants are even more reduced than those of seedless vascular plants such as ferns • An ovule consists of integuments, megaspore, and megasporangium. – A female gametophyte develops inside a megaspore and produces one or more egg cells. – A fertilized egg develops into a sporophyte embryo. – The whole ovule develops into a seed. Fig. 30.2 2. The four phyla of extant gymnosperms are ginko, cycads, gnetophytes, and conifers • There are four plant phyla grouped as gymnosperms. Fig. 30.4 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Gymnosperm only have tracheids - no vessels Vessels form contiunous tubes and thus are more specialized for transport of water and less for support. The thick lignified xylem cell helps in support Monocot Dicot one embryonic leaf - cotyledon two embryonic leaves - cotyledons does not have vascular cambium and secondary growth has vascular cambium and secondary growth scattered vascular bundles leaves have parallel venation no petioles flower parts in multiples of three vascular tissue arranged in circular bundles leaves have netted venation has petioles flower parts in multiples of four or five • Refinements in vascular tissue, especially xylem, probably played a role in the enormous success of angiosperms in diverse terrestrial habitats. – Like gymnosperms, angiosperms have long, tapered tracheids that function for support and water transport. – Angiosperms also have fibers cells, specialized for support, and vessel elements (in most angiosperms) that develop into xylem vessels for efficient water transport. Fig. 30.12 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings • A flower is a specialized shoot with four circles of modified leaves: sepals, petals, stamens, and carpals. Fig. 30.13a Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings • The life cycle of an angiosperm begins with the formation of a mature flower on a sporophyte plant and culminates in a germinating seed. Fig. 30.17 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings 3. Fruits help disperse the seeds of angiosperms • A fruit is a mature ovary. – As seeds develop from ovules after fertilization, the wall of the ovary thickens to form the fruit. – Fruits protect dormant seeds and/or aid in their dispersal. Fig. 30.15 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings 1. Absorptive nutrition enables fungi to live as decomposers and symbionts • Fungi are heterotrophs that acquire their nutrients by absorption. – They absorb small organic molecules from the surrounding medium. – Exoenzymes, powerful hydrolytic enzymes secreted by the fungus, digest food outside its body to simpler compounds that the fungus can absorb and use. Extracellular digestion. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings 2. Extensive surface area and rapid growth adapt fungi for absorptive nutrition • The vegetative bodies of most fungi are constructed of tiny filaments called hyphae that form an interwoven mat called a mycelium. Fig. 31.1 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Introduction • More than 100,000 species of fungi are known and mycologists estimate that there are actually about 1.5 million species worldwide. • Molecular analyses supports the division of the fungi into four phyla. Fig. 31.4 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings • The four fungal phyla can be distinguished by their reproductive features. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings • The fungal hyphae provides most of the lichen’s mass and gives it its overall shape and structure. • The algal component usually occupies an inner layer below the lichen surface. Fig. 31.17 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings • Mycorrhizae are mutualistic associations of plant roots and fungi. – The anatomy of this symbiosis depends on the type of fungus. • The extensions of the fungal mycelium from the mycorrhizae greatly increases the absorptive surface of the plant roots. • The fungus provides minerals from the soil for the plant, and the plant provides organic nutrients. Fig. 31.18 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings (3) The Bilateria can be divided by the presence or absence of a body cavity (a fluid-filled space separating the digestive tract from the outer body wall) and by the structure the body cavity. • Acoelomates (the phylum Platyhelminthes) have a solid body and lack a body cavity. Fig. 32.6a Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings • In some organisms, there is a body cavity, but it is not completely lined by mesoderm. – This is termed a pseudocoelom. – These pseudocoelomates include the rotifers (phylum Rotifera) and the roundworms (phylum Nematoda). Fig. 32.6b Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings • Coelomates are organisms with a true coelom, a fluid-filled body cavity completely lined by mesoderm. – The inner and outer layers of tissue that surround the cavity connect dorsally and ventrally to form mesenteries, which suspend the internal organs. Fig. 32.6b Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings • Many protostomes undergo spiral cleavage, in which planes of cell division are diagonal to the vertical axis of the embryo. – Some protostomes also show determinate cleavage where the fate of each embryonic cell is determined early in development. • The zygotes of many deuterostomes undergo radial cleavage in which the cleavage planes are parallel or perpendicular to the vertical egg axis. – Most deuterostomes show indeterminate cleavage whereby each cell in the early embryo retains the capacity to develop into a complete embryo. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings