chapter 16 plants, fungi, and the move onto land laura coronado bio 10 chapter 16
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Chapter 16 Chapter 16 Plants, Fungi, and the Move onto LandPlants, Fungi, and the Move onto Land
Chapter 16 Chapter 16 Plants, Fungi, and the Move onto LandPlants, Fungi, and the Move onto Land
Laura Coronado Bio 10 Chapter 16
Biology and Society: Will the Blight End the Chestnut?
– American chestnut trees• Once dominated forests of the eastern United States • Were prized for their– Rapid growth – Huge size– Rot-resistant wood
• Around 1900, an Asian fungus was accidentally introduced from China into North America, and in just 25 years, blight caused by the fungus killed virtually all adult American chestnut trees.
• Fortunately, this type of harmful interaction between plant and fungus is unusual.
• Many plants and fungi benefit from each other’s existence.Laura Coronado Bio 10 Chapter 16
Bacteria
Archaea
Eukarya
Protists
Plants
Fungi
Animals
Figure 16.UN01Laura Coronado Bio 10 Chapter 16
Terrestrial Adaptations of Plants Structural Adaptations
– Plants are terrestrial organisms that include forms that have returned to water, such as water lilies.
– A plant is• A multicellular eukaryote • A photoautotroph, making organic molecules by
photosynthesis– In terrestrial habitats, the resources that a
photosynthetic organism needs are found in two very different places: • Light and carbon dioxide are mainly available in the air • Water and mineral nutrients are found mainly in the soil
Laura Coronado Bio 10 Chapter 16
Terrestrial Adaptations of Plants Structural Adaptations
– The complex bodies of plants are specialized to take advantage of these two environments by having• Aerial leaf-bearing organs called shoots • Subterranean organs called roots
– Most plants have mycorrhizae, symbiotic fungi associated with their roots, in which the fungi• Absorb water and essential minerals from the soil• Provide these materials to the plant• Are nourished by sugars produced by the plant
Laura Coronado Bio 10 Chapter 16
Reproductivestructures (such asthose in flowers)contain sporesand gametes
Leaf performsphotosynthesis
Cuticle reduces waterloss; stomata regulategas exchange
Shoot supports plant(and may performphotosynthesis)
Surroundingwater supportsthe alga
Roots anchor plant;absorb water andminerals from thesoil (aided by fungi)
Whole algaperformsphotosynthesis;absorbs water,CO2, andminerals fromthe water
Alga
Plant
Figure 16.1Laura Coronado Bio 10 Chapter 16
Roots
Fungus
Rootsurroundedby fungus
Figure 16.2Laura Coronado Bio 10 Chapter 16
Plant Structures– Leaves are the main photosynthetic organs of most plants,
with• Stomata for the exchange of carbon dioxide and oxygen with the
atmosphere• Vascular tissue for transporting vital materials• A waxy cuticle surface that helps the plant retain water
– Vascular tissue in plants is also found in the• Roots • Shoots
– Two types of vascular tissue exist in plants:• Xylem transports water and minerals from roots to leaves • Phloem distributes sugars from leaves to the roots and other
nonphotosynthetic parts of the plant
Laura Coronado Bio 10 Chapter 16
Leaves
Gametangia
Stomata
Cuticle
Lignin
Shoot
Vascular tissues
Roots
Figure 16.UN07Laura Coronado Bio 10 Chapter 16
Phloem
Xylem
Oak leaf
Vasculartissue
Figure 16.3Laura Coronado Bio 10 Chapter 16
Reproductive Adaptations
– Plants produce their gametes in protective structures called gametangia, which have a jacket of protective cells surrounding a moist chamber where gametes can develop without dehydrating.
– The zygote develops into an embryo while still contained within the female parent in plants but not in algae.
Laura Coronado Bio 10 Chapter 16
Embryo
Maternaltissue
LM
Figure 16.4Laura Coronado Bio 10 Chapter 16
The Origin of Plants from Green Algae
– The algal ancestors of plants• Carpeted moist fringes of lakes or coastal salt marshes • First evolved over 500 million years ago
– Charophytes• Are a modern-day lineage of green algae • May resemble one of these early plant ancestors
Laura Coronado Bio 10 Chapter 16
LM
LM
Figure 16.5Laura Coronado Bio 10 Chapter 16
PLANT DIVERSITY & EVOLUTION
– The history of the plant kingdom is a story of adaptation to diverse terrestrial habitats.
– The fossil record chronicles four major periods of plant evolution.
– (1) About 475 million years ago plants originated from an algal ancestor giving rise to bryophytes, nonvascular plants, including mosses, liverworts, and hornworts that are nonvascular plants without• Lignified walls• True roots• True leaves
Laura Coronado Bio 10 Chapter 16
Ancestralgreen algae
Origin of first terrestrial adaptations(about 475 mya)
Origin of vascular tissue(about 425 mya)
Origin of seeds(about 360 mya)
600 500 400 300 200 100 0
Origin of flowers(about 140 mya)
Millions of years ago
Angiosperms
Gymnosperms
Ferns and otherseedless vascularplants
Bryophytes
Charophytes (a groupof green algae) Land plants
Vascular plantsSeed plantsSeedlessvascularplants
Nonvascular
plants(bryophytes)
Figure 16.6Laura Coronado Bio 10 Chapter 16
Bryophytes
Ferns
Gymnosperms
Angiosperms
Figure 16.UN02Laura Coronado Bio 10 Chapter 16
PLANT EVOLUTION– (2) About 425 million years ago ferns evolved
• With vascular tissue hardened with lignin• But without seeds
– (3) About 360 million years ago gymnosperms evolved with seeds that consisted of an embryo packaged along with a store of food within a protective covering but not enclosed in any specialized chambers.
– Today, conifers, consisting mainly of cone-bearing trees such as pines, are the most diverse and widespread gymnosperms.
– (4) About 140 million years ago angiosperms evolved with complex reproductive structures called flowers that bear seeds within protective chambers called ovaries.
Laura Coronado Bio 10 Chapter 16
Plant Diversity
– The great majority of living plants• Are angiosperms• Include fruit and vegetable crops, grains, grasses, and most
trees• Are represented by more than 250,000 species
Laura Coronado Bio 10 Chapter 16
PLANT DIVERSITY
Bryophytes(nonvascular plants)
Ferns(seedless vascular plants)
Gymnosperms(naked-seed plants)
Angiosperms(flowering plants)
Figure 16.7Laura Coronado Bio 10 Chapter 16
Bryophytes
–Bryophytes, most commonly mosses• Sprawl as low mats over acres of land• Need water to reproduce because their sperm
swim to reach eggs within the female gametangium• Have two key terrestrial adaptations:– A waxy cuticle that helps prevent dehydration – The retention of developing embryos within the mother
plant’s gametangium
Laura Coronado Bio 10 Chapter 16
Figure 16.8Laura Coronado Bio 10 Chapter 16
Spores
Spore capsule
Sporophyte
Gametophytes
Figure 16.9Laura Coronado Bio 10 Chapter 16
Mosses
– Mosses have two distinct forms:• The gametophyte, which produces gametes • The sporophyte, which produces spores
– The life cycle of a moss exhibits an alternation of generations shifting between the gametophyte and sporophyte forms.
– Mosses and other bryophytes are unique in having the gametophyte as the larger, more obvious plant.
Laura Coronado Bio 10 Chapter 16
Spores(n)
Sporecapsule
Gametes:sperm
and eggs(n)
Zygote(2n)
Gametophyte(n)
Sporophyte(2n)
Key
Haploid (n)
Diploid (2n)
MEIOSIS FERTILIZATION
osis
Mit osis
Mit
toMi
sis
Figure 16.10-5Laura Coronado Bio 10 Chapter 16
Ferns
– Ferns are• Seedless vascular plants • By far the most diverse with more than 12,000 known
species
– The sperm of ferns, like those of mosses• Have flagella • Must swim through a film of water to fertilize eggs
Laura Coronado Bio 10 Chapter 16
Spore capsule
“Fiddlehead”(young leavesready to unfurl)
Figure 16.11Laura Coronado Bio 10 Chapter 16
Carboniferous Period
– During the Carboniferous period, from about 360 to 300 million years ago, ferns• Were part of a great diversity of seedless plants • Formed swampy forests over much of what is now Eurasia
and North America
– As they died, these forests formed coal.– Fossil fuels• Include coal, oil, and natural gas • Formed from the remains of long-dead organisms
Laura Coronado Bio 10 Chapter 16
Figure 16.12Laura Coronado Bio 10 Chapter 16
Gymnosperms
– At the end of the Carboniferous period, the climate turned drier and colder, favoring the evolution of gymnosperms, which can • Complete their life cycles on dry land • Withstand long, harsh winters
– The descendants of early gymnosperms include the conifers, or cone-bearing plants.
Laura Coronado Bio 10 Chapter 16
Conifers
– Cover much of northern Eurasia and North America
– Are usually evergreens, which retain their leaves throughout the year
– Include the tallest, largest, and oldest organisms on Earth
Laura Coronado Bio 10 Chapter 16
Terrestrial Adaptations of Seed Plants– Conifers and most other gymnosperms have three
additional terrestrial adaptations:• Further reduction of the gametophyte• Pollen• Seeds
– Seed plants have a greater development of the diploid sporophyte compared to the haploid gametophyte generation.
– A pine tree or other conifer is actually a sporophyte with tiny gametophytes living in cones.
Laura Coronado Bio 10 Chapter 16
KeyHaploid (n)Diploid (2n)
Gametophyte(n) Sporophyte
(2n)
Sporophyte(2n)
Gametophyte(n)
Gametophyte(n)
Sporophyte(2n)
(a) Sporophyte dependenton gametophyte (e.g.,mosses)
(b) Large sporophyte and small,Independent gametophyte (e.g.,ferns)
(c) Reduced gametophytedependent on sporophyte(seed plants)
Figure 16.14Laura Coronado Bio 10 Chapter 16
Scale
Ovule-producingcones; the scalescontain femalegametophytes
Pollen-producingcones; theyproduce malegametophytes
Ponderosa pineFigure 16.15
Laura Coronado Bio 10 Chapter 16
Terrestrial Adaptations of Seed Plants
– A second adaptation of seed plants to dry land was the evolution of pollen.
– A pollen grain• Is actually the much-reduced male gametophyte • Houses cells that will develop into sperm
– The third terrestrial adaptation was the development of the seed, consisting of• A plant embryo • A food supply packaged together within a protective
coat
Laura Coronado Bio 10 Chapter 16
Seeds
– Develop from structures called ovules, located on the scales of female cones in conifers
– Can remain dormant for long periods before they germinate, as the embryo emerges through the seed coat as a seedling
Laura Coronado Bio 10 Chapter 16
(a) Ovule
Haploid (n)Diploid (2n)
(b) Fertilized ovule
(c) Seed
Cross sectionof scale
Female cone,cross section
Integument
Spore
Spore case
Pollen tube
Spore case
Egg nucleus
Femalegametophyte
Dischargedsperm nucleus
Seed coat(derived fromintegument)
Embryo(newsporophyte)
Food supply(derived fromfemalegametophytetissue)
Pollen grain(malegametophyte)
Figure 16.16-3Laura Coronado Bio 10 Chapter 16
Angiosperms
– Angiosperms• Dominate the modern landscape• Are represented by about 250,000 species• Supply nearly all of our food and much of our fiber for
textiles
– Their success is largely due to• A more efficient water transport • The evolution of the flower
Laura Coronado Bio 10 Chapter 16
Flowers, Fruits, & the Angiosperm Life Cycle
– Flowers help to attract pollinators who transfer pollen from the sperm-bearing organs of one flower to the egg-bearing organs of another.
– A flower is actually a short stem with four whorls of modified leaves:• Sepals• Petals• Stamens• Carpels
– Flowers are an essential element of the angiosperm life cycle & come in many forms
Laura Coronado Bio 10 Chapter 16
Petal
CarpelStamen
SepalOvule
Anther
Filament
Stigma
Style
Ovary
Figure 16.17Laura Coronado Bio 10 Chapter 16
Pansy Bleeding heart California poppy Water lily
Figure 16.18Laura Coronado Bio 10 Chapter 16
Maturesporophyteplant withflowers
Sporophyteseedling
Germinatingseed
Seed
Seed (developsfrom ovule)
Fruit (developsfrom ovary)
Embryo(sporophyte)
Twospermnuclei
Zygote
EndospermEmbryo sac(femalegametophyte)
Egg
FERTILIZATION
Key
Haploid (n)
Diploid (2n)
Anther at tip of stamen
Pollen tube growingdown style of carpel
Ovary (base of carpel)Ovule
Germinated pollen grain(male gametophyte) onstigma of carpel
Figure 16.19-6Laura Coronado Bio 10 Chapter 16
Seed Types
– Although both have seeds• Angiosperms enclose the seed within an ovary • Gymnosperms have naked seeds
– Fruit• Is a ripened ovary• Helps protect the seed• Increases seed dispersal• Is a major food source for animals
Laura Coronado Bio 10 Chapter 16
Winddispersal
Animaltransportation
Animalingestion
Figure 16.20Laura Coronado Bio 10 Chapter 16
Angiosperms and Agriculture
– Gymnosperms supply most of our lumber and paper.– Angiosperms• Provide nearly all our food • Supply fiber, medications, perfumes, and decoration
– Agriculture is a unique kind of evolutionary relationship between plants and animals.
Laura Coronado Bio 10 Chapter 16
Plant Diversity as a Nonrenewable Resource
– The exploding human population is• Extinguishing plant species at an unprecedented rate • Destroying fifty million acres, an area the size of the state
of Washington, every year!
– Humans depend on plants for thousands of products including• Food • Building materials • Medicines
Laura Coronado Bio 10 Chapter 16
Figure 16.21Laura Coronado Bio 10 Chapter 16
Table 16.1Laura Coronado Bio 10 Chapter 16
Plant Preservation
– Preserving plant diversity is important to many ecosystems and humans.
– Scientists are now rallying to• Slow the loss of plant diversity • Encourage management practices that use forests as
resources without damaging them
Laura Coronado Bio 10 Chapter 16
FUNGI
– Fungi• Recycle vital chemical elements back to the environment in
forms other organisms can assimilate • Form mycorrhizae, fungus-root associations that help plants
absorb from the soil– Minerals – Water • Eukaryotes • Typically multicellular• More closely related to animals than plants, arising from a
common ancestor about 1.5 billion years ago• Come in many shapes and sizes • Represent more than 100,000 species
Laura Coronado Bio 10 Chapter 16
Orange fungi
Mold
Predatory fungus
Budding yeastA “fairy ring”
Bud
Roundworm Body of fungus
Colo
rized
SEM
Colo
rized
SEM
Colo
rized
SEM
Figure 16.22Laura Coronado Bio 10 Chapter 16
Roundworm Body of fungus
Predatory fungus Colorized SEM
Figure 16.22fLaura Coronado Bio 10 Chapter 16
Characteristics of Fungi
– Fungi have unique• Structures • Forms of nutrition is chemoheterotrophs • Acquire their nutrients by absorption
– A fungus• Digests food outside its body• Secretes powerful digestive enzymes to break down the
food• Absorbs the simpler food compounds
Laura Coronado Bio 10 Chapter 16
Fungal Structure
– The bodies of most fungi are constructed of threadlike filaments called hyphae.
– Hyphae are minute threads of cytoplasm surrounded by a• Plasma membrane • Cell wall mainly composed of chitin
– Hyphae branch repeatedly, forming an interwoven network called a mycelium (plural, mycelia), the feeding structure of the fungus.
Laura Coronado Bio 10 Chapter 16
Reproductivestructure
MyceliumMycelium
Hyphae Spore-producingstructures
Figure 16.23Laura Coronado Bio 10 Chapter 16
Fungal Reproduction
– Mushrooms• Arise from an underground mycelium • Mainly function in reproduction
– Fungi reproduce by releasing billions and trillions of spores that are produced either sexually or asexually.
Laura Coronado Bio 10 Chapter 16
The Ecological Impact of Fungi
– Fungi have• An enormous ecological impact • Many interactions with humans
– Fungi and bacteria• Are the principal decomposers of ecosystems • Keep ecosystems stocked with the inorganic nutrients necessary
for plant growth
– Without decomposers, carbon, nitrogen, and other elements would accumulate in nonliving organic matter.
– Molds can destroy: Fruit, Grains, Wood, Human-made material
Laura Coronado Bio 10 Chapter 16
Parasitic Fungi– Parasitic fungi absorb nutrients from the cells or body
fluids of living hosts. – Of the 100,000 known species of fungi, about 30%
make their living as parasites, including• Dutch elm disease • Deadly ergot, which infests grain
– About 50 species of fungi are known to be parasitic in humans and other animals, causing• Lung and vaginal yeast infections • Athlete’s foot
Laura Coronado Bio 10 Chapter 16
(a) American elm trees killed by Dutchelm disease fungus
Figure 16.24a
Parasitic Fungi
(b) Ergots
Laura Coronado Bio 10 Chapter 16
The Process of Science: Did a Fungus Lead to the Salem Witch Hunt?
– Observation: In 1692, eight young girls were accused of being witches and had symptoms consistent with ergot poisoning.
– Question: Did an ergot outbreak cause the witch hunt?
– Hypothesis: The girls’ symptoms were the result of ergot poisoning.
– Prediction: The historical facts would be consistent with this hypothesis.
Laura Coronado Bio 10 Chapter 16
Figure 16.25Laura Coronado Bio 10 Chapter 16
The Process of Science: Did a Fungus Lead to the Salem Witch Hunt?
– Results:• Agricultural records from 1691, before the
symptoms appeared, indicated a particularly warm and wet year, in which ergot thrives.• Records from the following year, when accusations
of witchcraft died down, indicate a dry year consistent with an ergot die-off.• This correlation is consistent with the hypothesis
but not conclusive.
Laura Coronado Bio 10 Chapter 16
Commercial Uses of Fungi
– Fungi are commercially important. Humans eat them and use them to• Produce medicines such as penicillin• Decompose wastes• Produce bread, beer, wine, and cheeses
Laura Coronado Bio 10 Chapter 16
Truffles(the fungal kind, not the chocolates)
Blue cheese
Chanterellemushrooms
Figure 16.26Laura Coronado Bio 10 Chapter 16
Penicillium Zone of inhibited growth
Staphylococcus
Figure 16.27Laura Coronado Bio 10 Chapter 16
Evolution Connection: Mutually Beneficial Symbiosis
– Symbiosis is the term used to describe ecological relationships between organisms of different species that are in direct contact.
– Mutually beneficial symbiotic relationships benefit both species.
– Examples of mutually beneficial symbiotic relationships involving fungi include • Mycorrhizae, the association of fungi and plant roots• Lichens, the association of fungi and algae
Laura Coronado Bio 10 Chapter 16
Algal cell
Fungalhyphae
Colo
rized
SEM
Figure 16.28Laura Coronado Bio 10 Chapter 16