Biology, 9th ed, Sylvia Mader
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Transcript of Biology, 9th ed, Sylvia Mader
Biology, 9th ed, Sylvia Mader
Chapter 24 Evolution and Diversity of Plants Copyright The
McGraw-Hill Companies, Inc. Permission required for reproduction or
display. seed cones seed cones pollen cones a. A northern
coniferous forest of evergreen trees b. Cones of lodgepole pine,
Pinus contorta c. Fleshy seed cones of juniper, Juniperus a: Corbis
Royalty Free; b: Walt Anderson/Visuals Unlimited; c: The McGraw
Hill Companies, Inc./Evelyn Jo Johnson, photographer Outline
Evolutionary History Nonvascular Plants Vascular Plants
The Green Algal Ancestor Alternation of Generations Nonvascular
Plants Vascular Plants Seedless Seed Angiosperms Monocots and
Eudicots Flowers Evolutionary History of Plants
Plants are multicellular, photosyntheticeukaryotes. Plants
evolution is marked by adaptations to a land existence. A land
environment does offer certain advantages. Plentiful light for
photosynthesis Carbon dioxide is present in higher concentrations
and diffuses more readily in air than in water. Evolutionary
History of Plants
A land environment does offer certain advantages Constant threat of
desiccation (drying out). Protect all phases of reproduction
(sperm, egg, embryo) from drying out Seed plants disperse their
embryos within the seed, which provides the embryo with food within
a protective seed coat. The water environment provides plentiful
water. support for the body of the plant. Evolutionary History of
Plants
To conserve water, the land plant body, is covered by a waxy
cuticle. Impervious to water while still allowing carbon dioxide to
enter so that photosynthesis can continue Vascular system
transports water in the body of the land plant. Thought to have
evolved from freshwater green algaeover 450 mya Evolution of plants
marked by four evolutionary eventsassociated with four major groups
of plants Nonvascular Plants Advent of nourishment of a
multicellular embryo within the body of the female plant
Evolutionary History of Plants
Seedless vascular plants Advent of vascular tissue Gymnosperms and
angiosperms Produce seeds Flowering Plants Attract pollinators that
give rise to fruits Evolutionary History of Plants
Copyright The McGraw-Hill Companies, Inc. Permission required for
reproduction or display. flowers, double fertilization, endosperm,
fruit common ancestor seeds Flowering plants Seed megaphylls
Gymnosperms vascular tissue Vascular Ferns and allies apical growth
microphylls Seedless Lycophytes embryo protection Mosses Hornworts
Bryophytes Nonvascular common green algal ancestor Liverworts
Charophytes 550 500 450 400 350 300 250 PRESENT Million Years Ago
(MYA) Close Algal Relatives of Land Plant
Copyright The McGraw-Hill Companies, Inc. Permission required for
reproduction or display. Chara Coleochaete (Coleochaete): T.
Mellichamp/Visuals Unlimited; (Chara): Heather Angel/Natural
Visions INTERFOTO Pressebildagentur Alternation of
Generations
Life cycle involves alternation of generations Multicellular 1n
individuals (gametophytes) produce multicellular 2n individuals
(sporophytes) Multicellular 2n individuals (sporophytes) produce
multicellular 1n individuals (gametophytes) Sporophyte (2n):
Multicellular individual that produces spores by meiosis Spore is
haploid cell that will become the gametophyte Gametophyte (1n):
Multicellular individual that produces gametes Gametes fuse in
fertilization to form zygote Zygote is a diploid cell that will
become the sporophyte Alternation of Generations
Copyright The McGraw-Hill Companies, Inc. Permission required for
reproduction or display. sporophyte (2n) Mitosis sporangium (2n)
zygote (2n) diploid (2n) FERTILIZATION MEIOSIS haploid (n) (n)
spore (n) (n) gametes Mitosis Mitosis gametophyte (n) Alternation
of Generations
Appearance of generations varies widely In ferns, female portions
are archegonia and arefertilized by flagellated sperm In
angiosperm, female gametophyte (embryo sac),consists of an ovule
Following fertilization, ovule becomes seed In seed plants, pollen
grains are mature sperm-bearingmale gametophytes Reduction in the
Size of the Gametophyte
Copyright The McGraw-Hill Companies, Inc. Permission required for
reproduction or display. spores seed seed spores G a m e t o p h y
t e (n) S p o r o p h y t e (2n) roots roots rhizoids roots
rhizoids Moss Fern Gymnosperm Angiosperm Other Terrestrial
Adaptations
Vascular tissue transports water andnutrients to the body of the
plant Cuticle provides an effective barrier towater loss Stomata
bordered by guard cells thatregulate opening, and thus water loss
Leaf Adaptation cuticle a. Stained photomicrograph
Copyright The McGraw-Hill Companies, Inc. Permission required for
reproduction or display. cuticle a. Stained photomicrograph of a
leaf cross section Plant leaves have a Cuticle and stomata Stomata
Stomata 400 x b. Falsely coloured scanning Electron micrograph of
leaf surface (Left): Kingsley Stern; (Right): Andrew Syred/SPL
/Photo Researchers, Inc. Nonvascular Plants: Bryophytes
Lack specialized means of transporting water andorganic nutrients
Do not have true roots, stems, and leaves Gametophyte is dominant
generation Produces eggs in archegonia Produces flagellated sperm
in antheridia Sperm swim to egg in film of water to make zygote
Nonvascular Plants Hornworts (phlym Anthocerophyta) have
smallsporophytes that carry on photosynthesis Liverworts (phylum
Hepatophyta) have eitherflattened thallus or leafy appearance
Mosses (phylum Bryophyta) usually have a leafyshoot, although some
are secondarily flattened Can reproduce asexually by fragmentation
Dependent sporophyte consists of foot, stalk, andsporangium B.
Runk/S. Schoenberger/Grant Heilman Photography
Hornwort Copyright The McGraw-Hill Companies, Inc. Permission
required for reproduction or display. sporophyte gametophyte B.
Runk/S. Schoenberger/Grant Heilman Photography Liverwort,
Marchantia male gametophyte female gametophyte gemma cup
Copyright The McGraw-Hill Companies, Inc. Permission required for
reproduction or display. male gametophyte female gametophyte gemma
cup thallus rhizoids gemma a. Thallus with gemmae cups b. Male
gametophytes bear antheridia c. Female gametophytes bear archegonia
a: Ed Reschke/Peter Arnold, Inc.; b: J.M. Conrarder/National
Audubon Society/Photo Researchers, Inc.; c: R. Calentine/Visuals
Unlimited Moss (Polytrichum) Life Cycle
Copyright The McGraw-Hill Companies, Inc. Permission required for
reproduction or display. 4. The sporophyte: The mature sporophyte
has a foot buried in female gametophyte tissue, a stalk, and an
upper capsule (the sporangium), where meiosis occurs and spores are
developing sporophyte 3. The zygote: The zygote and developing
sporophyte are retained within the archegonium. capsule 5. The
spores: When the calyptra and lid (operculum) of a capsule fall
off, the spores are mature. One or two rings of teeth project
inward from the margin of the capsule. The teeth close the opening,
except when the weather is dry. Sporangium calyptra Mitosis stalk
Sporophyte teeth operculum zygote diploid (2n) FERTILIZATION
MEIOSIS haploid (n) 2. Fertilization: Flagellated sperm produced in
antheridia swim in external water to archegonia, each bearing a
single egg. egg foot (n) Spores sperm 6. Spore dispersal: Spores
are released when they are most likely to be dispersed by air
currents. Mitosis Archegonia buds Antheridia Protonema 1. The
mature gametophytes: In mosses, the leafy gametophyte shoots bear
either antheridia or archegonia, where gametes are 7. The immature
gametophyte: A spore germinates into a male or female protonema,
the first stage of the male and the female gametophytes.
Gametophytes rhizoids (Top): Heather Angel/Natural Visions;
(Bottom): Bruce Iverson Vascular Plants Dominate the natural
landscape
Xylem conducts water and dissolved minerals up from roots Phloem
conducts sucrose and other organic compounds throughout the plant
Lignin strengthens walls of conducting cells in xylem Most seedless
vascular plants are homosporous Windblown spores are dispersal
agents All seed plants are heterosporous and have male and female
gametophytes Seeds disperse offspring Seedless Vascular Plants:
Lycophyta
Club Mosses (phylum Lycophyta) Typically, branching rhizome sends
up short aerialstems Leaves are microphylls (have only one strand
ofvascular tissue) Most likely evolved as simple side extensions of
thestem Sporangia occur on surfaces of sporophylls Grouped into
club-shaped strobili Seedless Vascular Plants
Roots evolved simply as lower extensions of the stem Todays
lycophytes, also called club mosses, include three groups of 1,150
species: Ground pines (Lycopodium), Spike mosses (Selaginella), and
Quillworts (Isoetes) Ground Pine sporangia strobili sporophyll
Strobilus leaves
Copyright The McGraw-Hill Companies, Inc. Permission required for
reproduction or display. sporangia strobili sporophyll Strobilus
leaves (microphylls) stoma branches vascular tissue Leaf xylem
phloem arial stem rhizome root Root Courtesy Hans Steur, the
Netherlands
Cooksonian Fossil Copyright The McGraw-Hill Companies, Inc.
Permission required for reproduction or display. sporangia Courtesy
Hans Steur, the Netherlands Seedless Vascular Plants:
Pteridophytes
Includes Ferns and their Allies (horsetails andwhisk ferns) Have
megaphylls (broad leaves) Allow plants to efficiently collect solar
energy, Produce more food and the possibility of producing
moreoffspring than plants without megaphylls. Horsetails Rhizome
produces tall aerial stems Contains whorls of slender, green
branches Small, scalelike leaves also form whorls at the joints
Robert P. Carr/Bruce Coleman, Inc.
Horsetail, Equisetum Copyright The McGraw-Hill Companies, Inc.
Permission required for reproduction or display. strobilus branches
node leaves rhizome root Robert P. Carr/Bruce Coleman, Inc.
Microphylls and Megaphylls
Copyright The McGraw-Hill Companies, Inc. Permission required for
reproduction or display. single strand of vascular tissue branched
vascular tissue a. Microphyll Megaphyll One branch began to
dominate the stem system. The side branches flattened into a single
plane. Tissue filled in the spaces between the side branches.
branched stem system megaphyll leaf b. Megaphyll evolution process
Ferns Whisk Ferns (phylum Psilotophyta) Ferns (phylum
Pterophyta)
Branched rhizome has rhizoids Mutualistic mycorrhizal fungus helps
gather nutrients Ferns (phylum Pterophyta) Large conspicuous fronds
Divided into leaflets Dominant sporophyte produces windblown spores
Whisk fern, Psilotum sporangium scale aerial stem root
rhizome
Copyright The McGraw-Hill Companies, Inc. Permission required for
reproduction or display. sporangium scale aerial stem root rhizome
CABISCO/Phototake Diversity of Ferns spores on fertile frond
stipe
Copyright The McGraw-Hill Companies, Inc. Permission required for
reproduction or display. spores on fertile frond stipe Cinnamon
fern, Osmunda cinnamomea frond (undivided) frond (divided) axis
leaflet Hart's tongue fern, Campyloneurum scolopendrium Maidenhair
fern, Adiantum pedatum CABISCO/Phototake Matt Meadows/Peter Arnold,
Inc.
Fern Life Cycle Copyright The McGraw-Hill Companies, Inc.
Permission required for reproduction or display. 7. The fronds: The
sporophyte develops a root- bearing rhizome from which the aerial
fronds project. 1. The sporophyte: The sporophyte is dominant in
ferns. sori Sporophyte Dryopterus 6. The zygote: The resulting
sporophyte zygote begins its development inside an archegonium. As
the distinctive first leaf appears above the prothallus, and as the
roots develop below it, the sporophyte becomes visible. leaflet
sporangium Sorus young sporophyte on gametophyte fiddlehead rhizome
roots 2. The sporangia: In this fern, the sporangia are located
within sori (sing., sorus), on the underside of Mitosis annulus
zygote diploid (2n) Sporangium FERTILIZ A TION MEIOSIS haploid (n)
5. Fertilization: Fertilization takes place when moisture is
present, because the flagellated sperm must swim in a film of water
from the antheridia to the egg within 3. The spores: Within a
sporangium, meiosis occurs and spores are produced. When a
sporangium opens, the spores are egg Spores prothallus (underside)
sperm Archegonium Mitosis germinating spore Antheridium 4. The
gametophyte: A spore germinates into a prothallus (the
gametophyte), which typically bears archegonia at the notch and
antheridia at the Gametophyte rhizoids Matt Meadows/Peter Arnold,
Inc. The Uses of Ferns Edible ferns are used as a food source
Harbor nitrogen-fixing cyanobacteria Azolla is grown in rice
paddies, where it fertilizes rice plants. Ferns and their allies
are used as medicines in China. Extracts from ferns have also been
used to kill insects Used as decoration Seed Plants Seed plants are
the most plentiful plants in the biosphere
Seed coat and stored food allow an embryo tosurvive harsh
conditions during long period ofdormancy Heterosporous
Drought-resistant pollen grains Ovule develops into seed Seed
Plants seed cones seed cones pollen cones
Copyright The McGraw-Hill Companies, Inc. Permission required for
reproduction or display. seed cones seed cones pollen cones a. A
northern coniferous forest of evergreen trees b. Cones of lodgepole
pine, Pinus contorta c. Fleshy seed cones of juniper, Juniperus a:
Corbis Royalty Free; b: Walt Anderson/Visuals Unlimited; c: The
McGraw Hill Companies, Inc./Evelyn Jo Johnson, photographer
Gymnosperms Gymnosperms have ovules and seedsexposed on the surface
of sporophylls Conifers Cycads Ginkgoes Gnetophytes Conifers
Conifers, as well as other gymnosperm phyla, bear cones
Tough, needlelike leaves of pines conservewater with a thick
cuticle and recessed stomata Considered a soft wood because it
consistsprimarily of xylem tissue Pine Life Cycle Copyright The
McGraw-Hill Companies, Inc. Permission required for reproduction or
display. 1. The pollen cones: Typicall y , the pollen cones are
quite small and develop near the tips of lower branches. The seed
cones: The seed cones are larger than the pollen cones and are
located near the tips of higher branches. 7. The sporophyte: After
fertilization, the ovule matures and becomes the seed composed of
the embryo, reserve food, and a seed coat. Finally, in the fall of
the second season, the seed cone, by now woody and hard, opens to
release winged seeds. When a seed germinates, the sporophyte embryo
develops 2. The pollen sacs: A pollen cone has two pollen sacs
(microsporangia) that lie on the underside of each scale.
Sporophyte seed wing pollen cones seed cone The ovules: The seed
cone has two ovules (megasporangia) that lie on the upper Pollen
sac (microsporangium) Ovule (megasporangium) embryo seed coat
stored food pollen cone scale seed cone scale seed mitosis 3. The
microspores: Within the pollen sacs, meiosis produces four
microspores. zygote microspore mother cell megaspore mother cell 6.
The zygote: Once a pollen grain reaches a seed cone, it becomes a
mature male gametophyte. Apollen tube digests its way slowly toward
a female gametophyte and discharges two nonflagellated sperm. One
of these fertilizes an egg in an archegonium, and a zygote results.
diploid (2n) FERTILIZATION haploid (n) MEIOSIS MEIOSIS The
megaspore: W ithin an ovule, meiosis produces four megaspores, only
one survives. Mature female gametophyte Pollen grain Microspores
archegonium Mitosis Megaspore ovule wall Pollination ovule wall 4.
The pollen grains: Each microspore becomes a pollen grain, which
has two wings and is carried by the wind to the seed cone during
pollination. Mature male gametophyte mitosis pollen tube pollen
grain sperm 5. The mature female gametophyte: Only one of the
megaspores undergoes mitosis and develops into a mature female
gametophyte, having two to six archegonia. Each archegonium
contains a single large egg lying near the ovule opening. 200 m The
Uses of Pine Used in construction of all sorts.
Although technically a softwood, some pinewoods are actually harder
than so-called hardwoods. The foundations of the Brooklyn Bridge
are made of Southern yellow pine. Used for parks and gardens, and
Christmas decorations. Pine needles are rich in vitamins A and C.
Used as a medicine Pine oil is distilled from the twigs and needles
of Scotch pines and used to scent a number of household and
personal care products Cycads Cycads (phylum Cycadophyta)
Large, finely divided leaves that grow inclusters at the top of the
stem Pollen and seed cones on separate plants Pollinated by insects
Ginkgoes Ginkgoes (phylum Ginkgophyta) Dioecious
Some trees producing seeds Others producing pollen One surviving
species (Gingko biloba) The Ginkgo Tree ovule seed b. Ginkgo
biloba, a native of China
Copyright The McGraw-Hill Companies, Inc. Permission required for
reproduction or display. ovule seed b. Ginkgo biloba, a native of
China b(Main): Runk/Schoenburger/Grant Heilman Photography;
b(Inset): Courtesy Ken Robertson, University of Illinois/INHS
c(Main): Daniel L. Nickrent; c(Inset): Courtesy K.J. Niklas
Ephedra Copyright The McGraw-Hill Companies, Inc. Permission
required for reproduction or display. leaves microsporangia c.
Ephedra, a type of genetophyte c(Main): Daniel L. Nickrent;
c(Inset): Courtesy K.J. Niklas Welwitschia miribilis
Copyright The McGraw-Hill Companies, Inc. Permission required for
reproduction or display. pollen cones leaf d. Welwitschia
mirabilis, a type of gnetophyte NHPA/Steve Robinson Gnetophytes
Gnetophytes (phylum Gnetophyta)
Have similarly structured xylem None have archegonia Strobili have
similar construction Angiosperms Angiosperms (phylum
Anthophyta)
An exceptionally large and successful group ofplants Ovules are
always enclosed within diploid tissues Became dominant group of
plants in the lateCretaceous and early Paleocene periods Amborella
trichopoda Copyright The McGraw-Hill Companies, Inc. Permission
required for reproduction or display. Courtesy Stephen
McCabe/Arboretum at University of California Santa Cruz Monocots
and Eudicots Two classes of flowering plants
Monocotyledones (Monocots) One cotyledon in seed Eudicotyledones
(Dicots) Two cotyledons in seed Flower Diversity Beavertail cactus,
Opuntia basilaris
Copyright The McGraw-Hill Companies, Inc. Permission required for
reproduction or display. Beavertail cactus, Opuntia basilaris Water
lily, Nymphaea odorata Blue flag iris, Iris versicolor Snow
trillium, Trillium nivale Apple blossom, Malus domestica Butterfly
weed, Asclepias tuberosa (Cactus): Christi Carter/Grant Heilman
Photography; (Butterfly weed): Evelyn Jo Johnson; (Water lily): Pat
Pendarvis; (Iris): David Cavagnaro/Peter Arnold, Inc.; (Trillium):
Adam Jones/Photo Researchers, Inc.; (Apple blossoms): Inga
Spence/Photo Researchers, Inc. The Flower Peduncle (flower stalk)
expands at tip into a receptacle
Bears sepals, petals, stamens, and carpels, allattached to
receptacle in whorls Calyx (collection of sepals) protect flower
budbefore it opens Corolla (collection of petals) The Flower Each
stamen consists of an anther and a filament (stalk)
Carpel has three major regions Ovary - Swollen base Fruit Style -
Elevates stigma Stigma - Sticky receptor of pollen grains
Generalized Flower anther stigma pollen tube filament style
ovary
Copyright The McGraw-Hill Companies, Inc. Permission required for
reproduction or display. anther stigma pollen tube filament style
ovary stamens ovule carpel receptacle petals (corolla) sepals
(calyx) Flowering Plant Life Cycle
Copyright The McGraw-Hill Companies, Inc. Permission required for
reproduction or display. Stamen Carpel anther stigma filament style
2. The pollen sacs: In pollen sacs (microsporangia) of the anthe ,
meiosis produces microspores. ovary The ovules: In an ovule
(megasporangium) within an ovary, meiosis produces four megaspores.
ovule 7. The sporophyte: Theembryo within a seed is the immature
sporophyte. When a seed germinates, growth and differentiation
produce the mature sporophyte of a flowering plant. r Mitosis
stigma fruit (mature ovary) Sporophyte 1. The stamen: An anther at
the top of a stamen has four pollen sacs. Pollen grains are
produced in pollen Pollen sac (microsporangium) Ovule
(megasporangium) style seed (mature ovule) 6. The seed: The ovule
now develops into the seed, which contains an embryo and food
enclosed by a protective seed coat. The wall of the ovary and
sometimes adjacent parts develop into a fruit that The carpel: The
ovary at the base of a carpel contains one or more ovules. The
contents of an ovule change during the flowering plant life cycle.
ovary seed coat embryo Anther endosperm (3n) Seed diploid (2n)
FERTILIZATION MEIOSIS MEIOSIS haploid (n) Pollen grain (Mature male
gametophyte) tube cell 5. Double fertilization: On reaching the
ovule, the pollen tube discharges the sperm. One of the two sperm
migrates to and fertilizes the egg, forming a zygote; the other
unites with the two polar nuclei, producing a 3n (triploid)
endosperm nucleus. The endosperm nucleus divides to form
Pollination mitosis generative cell ovule wall Microspores
Megaspores pollen tube polar nuclei sperm ovule wall sperm
antipodals egg pollen tube tube cell nucleus polar nuclei
degenerating megaspores egg mitosis synergids Embryo sac (mature
female gametophyte) 3. The microspores: Each microspore in a pollen
sac undergoes mitosis to become an immature pollen grain with two
cells: the tube cell and the generative cell. The pollen sacs open,
and the pollen grains are windblown or carried by an animal
carrier, usually to other flowers. This is pollination. 4. The
mature male gametophyte: Apollen grain that lands on the carpel of
the same type of plant germinates and produces a pollen tube, which
grows within the style until it reaches an ovule in the ovary.
Inside the pollen tube, the generative cell nucleus divides and
produces two nonflagellated sperm. A fully germinated pollen grain
is the mature The mature female gametophyte: The ovule now contains
the mature female gametophyte (embryo sac), which typically
consists of eight haploid nuclei embedded in a mass of cytoplasm.
The cytoplasm differentiates into cells, one of which is an egg and
another of which contains two polar nuclei. The megaspores: Inside
the ovule of an ovar y , three megaspores disintegrate, and only
the remaining one undergoes mitosis to become a female gametophyte.
Flowers and Diversification
Wind-pollinated flowers are usually not showy Bird-pollinated
flowers are often colorful Night-blooming flowers attract
nocturnalmammals or insects Usually white or cream-colored Fruits
of flowers protect and aid in dispersal Utilize wind, gravity,
water, and animals for dispersal Uses of Plants Plants define and
are the producers in most ecosystems.
Humans derive most of their sustenance from three flowering plants:
wheat, corn, and rice Simple carbohydrate such as sugar comes
almost exclusively from two plants: sugarcane and sugar beets Our
most popular drinkscoffee, tea, and cola are also from flowering
plants Cereal Grains ear Wheat plants, Triticum Corn plants,
Zea
Copyright The McGraw-Hill Companies, Inc. Permission required for
reproduction or display. grain head grain head ear Wheat plants,
Triticum Corn plants, Zea Rice plants, Oryza (Wheat): Pixtal/age
fotostock; (Rice): Corbis Royalty Free; (Rice grain): Dex
Image/Getty RF; (Cornfield): Corbis; (Corn ear): Nigel
Cattlin/Photo Researchers, Inc. Uses of Plants Copyright The
McGraw-Hill Companies, Inc. Permission required for reproduction or
display. a. Dwarf fan palms, Chamaerops, for basket weaving b.
Rubber, Hevea, for auto tires d. Tulips, Tulipa, for beauty c.
Cotton, Gossypium, for cloth a: Heather Angel/Natural Visions; b:
Steven King/Peter Arnold, Inc.; c: Dale Jackson/Visuals Unlimited;
d: Brand X Pictures/PunchStock Review Evolutionary History
Nonvascular Plants Vascular Plants
The Green Algal Ancestor Alternation of Generations Nonvascular
Plants Vascular Plants Seedless Seed Angiosperms Monocots and
Eudicots Flowers Biology, 9th ed, Sylvia Mader
Chapter 24 Evolution and Diversity of Plants Copyright The
McGraw-Hill Companies, Inc. Permission required for reproduction or
display. seed cones seed cones pollen cones a. A northern
coniferous forest of evergreen trees a: Corbis Royalty Free; b:
Walt Anderson/Visuals Unlimited; c: The McGraw Hill Companies,
Inc./Evelyn Jo Johnson, photographer b. Cones of lodgepole pine,
Pinus contorta c. Fleshy seed cones of juniper, Juniperus