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PowerPoint® Lecture Slides forEssential Biology, Second Edition & Essential Biology with Physiology
Neil Campbell, Jane Reece, and Eric Simon
Presentation prepared by Chris C. Romero
CHAPTER 16CHAPTER 16
Plants, Fungi, and the Move onto LandFigures 16.1 – 16.5
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• Some giant sequoia trees weigh more than a dozen space shuttles
• Flowering plants such as corn, rice, and wheat provide nearly all our food.
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• A mushroom is probably more closely related to humans than it is to any plant
• Every 2 seconds humans destroy an area of tropical rain forest equal to the area of 3 football fields.
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• Coniferous forests are highly productive
BIOLOGY AND SOCIETY:
THE BALANCING ACT OF FOREST CONSERVATION
– They provide lumber for building and wood pulp for paper.
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• Our demand for wood and paper is so great that clear-cut areas have become commonplace.
Figure 16.1
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• The loss of coniferous forests
– Threatens the trees and other organisms that live in forests
– Can be minimized by conservation practices.
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• Plants
COLONIZING LAND
– Are terrestrial organisms
– Are multicellular eukaryotes that make organic molecules by photosynthesis.
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• Living on land poses different problems from living in water
Terrestrial Adaptations of PlantsStructural Adaptations
– Plants require structural specializations
– Roots and shoots.
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Figure 16.2
PlantLeafperforms photosynthesis
Cuticlereduces water loss; stomata allow gas exchange
Shootsupports plant (and may perform photosynthesis)
Alga Surrounding water supports the alga
Whole algaperformsPhoto-synthesis;absorbs
water, CO2,and mineralsfrom the water
Rootsanchor plant;absorb water and mineralsfrom the soil (aided by fungi)
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• Most plants have mycorrhizae, symbiotic fungi associated with their roots.
Figure 16.3
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• Leaves
– Are the main photosynthetic organs of most plants
– Have stomata for gas exchange
– Contain vascular tissue for transporting vital materials.
Figure 16.4
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• Other types of vascular tissue are found in the roots and shoots of plants.
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• Plants produce their gametes in protective structures called gametangia.
Reproductive Adaptations
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• In plants, but not algae, the zygote develops into an embryo while still contained within the female parent.
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Figure 16.5
Ovary of flower
Embryo
Maternal tissue
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The Origin of Plants from Green Algae
• The move onto land and the spread of plants to diverse terrestrial environments were incremental
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• Molecular comparisons and other evidence place a group of green algae called charophyceans closest to plants.
Figure 16.6
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• The history of the plant kingdom is a story of adaptation to diverse terrestrial habitats.
PLANT DIVERSITY
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Highlights of Plant Evolution
• The fossil record chronicles four major periods of plant evolution.
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Figure 16.7
Cen
ozo
icM
esoz
oic
Pal
eozo
ic Ch
arop
hyc
ean
s (a
gro
up
of
gre
en a
lgae
)
Bry
oph
ytes
(e.
g.,
mos
ses)
See
dle
ss v
ascu
lar
pla
nts
(e
.g.,
fern
s)
Gym
nos
per
ms
(e.g
., co
nife
rs)
An
gio
-sp
erm
s
Origin of plants
Early vascular plants
First seed plants
Diversification of flowering plants
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• The first period
– Was the origin of plants from their aquatic ancestors, charophyceans
• The second period
– Was the diversification of vascular plants
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• The third period
– Began with the origin of the seed
• The fourth period
– Was the emergence of flowering plants, or angiosperms.
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Bryophytes
• Mosses
Figure 16.8
– Are the most familiar bryophytes.
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• Mosses display two key terrestrial adaptations
– A waxy cuticle that helps prevent dehydration
– The retention of developing embryos within the mother’s gametangium.
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• Mosses have two distinct versions of the plant
– The gametophyte, which produces gametes
– The sporophyte, which produces spores.
Figure 16.9
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• The life cycle of a moss exhibits an alternation of generations.
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Figure 16.10
Sporesn Mito
sis
Sporophyte2n
Mitosis
Gametes (sperm and
eggs)n
Fertilization
Zygote2n
Mitosis
Spore capsule
Meiosis
Gametophyten
Haploid
Diploid
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Ferns
• Ferns
Figure 16.11
– Are seedless vascular plants.
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• During the Carboniferous period, about 290–360 million years ago, ferns formed swampy forests that covered much of what is now Eurasia and North America
– These forests formed what would become fossil fuels.
Figure 16.12
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Gymnosperms
• A drier, colder climate at the end of the Carboniferous period favored the evolution of gymnosperms, the first seed plants.
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• Conifers
Conifers
– Cover much of northern Eurasia and North America
– Are usually evergreens, which retain their leaves throughout the year.
Figure 16.13
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• Conifers and most other gymnosperms have three terrestrial adaptations
Terrestrial Adaptations of Seed Plants
– Further reduction of the gametophyte
– The evolution of pollen
– The advent of the seed.
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• The first adaptation is a greater development of the diploid sporophyte compared to the haploid gametophyte generation.
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Figure 16.14
Gametophyte (n)
Sporophyte (2n)
(a) Sporophytedependent on gametophyte (e.g., mosses)
Sporophyte (2n)
Gametophyte (n)
(b) Large sporophyte and small, independent gametophyte (e.g., ferns)
Sporophyte (2n)
Gametophyte (n)
(c) Reduced gametophyte dependent on sporophyte (seed plants)
Haploid (n)
Diploid (2n)
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• A pine tree of other conifer is actually a sporophyte with tiny gametophytes living in cones.
Figure 16.15
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• A second adaptation of seed plants to dry land was the evolution of pollen
• A pollen grain
– Is actually the much-reduced male gametophyte
– Fertilizes the female gametophyte.
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• The third terrestrial adaptation was the development of the seed
• A seed consists of a plant embryo packaged along with a food supply within a protective coat.
Figure 16.16
Integuments
Spore
(a) Ovule
Haploid (n)
Diploid (2n)
Pollen tube
Pollen grain(male gametophyte)
Female gametophyte
Egg nucleus
Discharged sperm nucleus
(b) Fertilized ovule
Seed coat (derived from integuments)
Food supply (derived from female gametophyte tissue)
Spore case
Embryo(new sporophyte)
(c) Seed
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Angiosperms
• Angiosperms
– Supply nearly all our food and much of our fiber for textiles
• More efficient water transport and the evolution of the flower help account for the success of the angiosperms.
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• The dominant stage of the angiosperms is a sporophyte with gametophytes in its flowers.
Flowers, Fruits, and the Angiosperm Life Cycle
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Figure 16.17
Stamen
Anther
Filament
Ovule
Petal
CarpelStigma
Style
Ovary
Sepal
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• The life cycle of an angiosperm.
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Mature sporophyteplant with flowers
Germinated pollen grain (male gametophyte) on stigma of carpel
Anther at tip of stamen
Pollen tube growing down style of carpel
Ovary (base of carpel)
Embryo sac (female gametophyte)
Egg
Sperm nuclei
Fertilization
Endosperm
Zygote
Embryo (sporophyte)
Fruit (develops from ovary)
Seed (develops from ovule)
Seed
Germinating seed
Sporophyte seedling
Haploid (n)
Diploid (2n)
Ovule
Figure 16.18
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• The seed being enclosed within an ovary distinguishes angiosperms from gymnosperms.
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• A fruit
– Is a ripened ovary
– Helps protect the seed and increase seed dispersal
– Is a major food source for animals.
Figure 16.19
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• Angiosperms
Angiosperms and Agriculture
– Supply fiber, medications, perfumes, and decoration
• Agriculture
– Is a unique kind of evolutionary relationship between plants and animals.
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Plant Diversity as a Nonrenewable Resource
• The exploding human population is extinguishing plant species at an unprecedented rate.
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• Humans depend on plants for thousands of products including food, building materials, and medicines.
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Table 16.1
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• Preserving plant diversity is important to many ecosystems as well as humans.
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• Fungi are extremely important to ecosystems because they decompose and recycle organic materials.
FUNGI
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• Fungi
– Are eukaryotes, and most are multicellular
– Are more closely related to animals than plants.
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• A gallery of diverse fungi
Figure 16.20
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Characteristics of Fungi
• In this section, the structure and function of fungi are described.
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• Fungi are heterotrophs
Fungal Nutrition
– They digest their food externally and acquire the nutrients by absorption.
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• The bodies of most fungi are constructed of structures called hyphae.
Fungal Structure
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• The hyphae
– Form an interwoven mat called a mycelium
– Are separated into cells by cross-walls made mainly of chitin.
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Figure 16.21
Hyphae
Reproductive structure
Spore-producing structures
Mycelium
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• Fungi reproduce by releasing spores that are produced either sexually or asexually.
Fungal Reproduction
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The Ecological Impact of Fungi
• Fungi
– Have an enormous ecological impact.
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• Fungi and bacteria
Fungi as Decomposers
– Are the principal decomposers of ecosystems
– Keep ecosystems stocked with nutrients necessary for plant growth.
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• Molds
– Can destroy fruit, wood, and human-made materials.
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• Of the 100,000 known species of fungi, about 30% make their living as parasites.
Parasitic Fungi
Figure 16.22
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• About 50 species of fungi are known to be parasitic in humans and other animals.
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• Fungi are commercially important
Commercial Uses of Fungi
– As food and in baking
– In beer and wine production.
Figure 16.23
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• Some fungi produce antibiotics.
Figure 16.24
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• Interdependence between species, or symbiosis, is an evolutionary product
EVOLUTION CONNECTION:
MUTUAL SYMBIOSIS
– Mutualism is symbiosis that benefits both species.
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• Lichens
– Are symbiotic associations between fungi and algae.
Figure 16.25
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SUMMARY OF KEY CONCEPTS
Visual Summary 16.1
Leaves are main photosynthetic organs
Gametangia protect gametes from dehydration; female gametangia protect developing embryos
Cuticle reduces water loss
Stomata allow gas exchange between plant and atmosphere
Lignin hardens cell walls
Shoot supports plant; may perform photosynthesis
Vascular tissues transport water, minerals, and sugars; provide support
Roots anchor plant; mycorrhizae(root/fungus associations) help absorb water and minerals from the soil)
• Terrestrial Adaptations of Plants.
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• Highlights of Plant Evolution.
Visual Summary 16.2
Origin of gametangia
(protect gametes and
embryos)
Diversification of seedless
vascular plants (vascular tissue conducts water and nutrients)
Origin of seeds (protect embryos from desiccation
and other hazards)
Origin of flowers (bear ovules
within protective chambers called
ovaries)