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Although the diversification of (during the Green Explosion) occurred before the diversification of green plants, the move towards terrestrial began with the green plants. Include: • Green diversification: Cambrian: about 540 million ago • Land Plants First land plants: : over 400 million years ago First land animals: slightly later Do not include: • Red or The of land plants was marked by important changes that • Fungi ! permitted them to live and thrive outside of an aquatic environment. Green Plants Animals Fungi Unlike aquatic algae, land plants must cope with: • new ways to get water and Note that fungi are • new ways to transport water and nutrients more closely related • the problem of dessication • non-aqueous fertilization to animals than to • sudden and severe environmental changes plants. • gravity

BRYOPHYTES Land plants we will learn: • include and liverworts

• Bryophytes (mosses and liverworts) • Small bodied plants that cannot be fully independent of standing water; thus, they tend to live in damp places. • Tracheophytes (vascular plants) • Wet provide a medium for water transport, and fertilization • Lycopods • Horsetails • • Seed plants • “Gymnosperms” • lineages • • Angiosperms (flowering plants) • Monocots • Dicots liverworts

1 life cycles are characterized by alternation of TRACHEOPHYTES: Vascular plants generation, with the green gametophyte being the dominant phase. The haploid are produced in sporangia capsules during the sporophyte phase. In a moss, the sporophyte phase performs but is somewhat parasitic on the gametophyte phase.

capsule • The evolution of a vascular system in the sporophyte phase made possible the transport of water and nutrients up from spores the soil and around the itself.

2N sporophyte Haploid • allowed land plants to become independent of standing water, spores will and to colonize more kinds of terrestrial habitats germinate and grow into • All land plants except mosses and liverworts are vascular plants. 1N gametophyte new haploid (1N) gametophytes

Lycopods and Horsetails: ancient lineages that still survive today Giant tree-like lycopods and horsetails were some of the dominant land plants during a period of we now call the , • Lycopods and horsetails were the first to evolve differentiated and from 300 to 350 million years ago. Most of the coal we use today specialized body parts within the sporophyte phase, resulting was formed from these extinct tree-like giants. in true , stems, and .

lycopods horsetails giant lycopod Fossil giant horsetail

< Simulated Carboniferous swamp

2 Ferns THE EVOLUTION OF THE SEED • Up to this point, no plants we have discussed have seeds Like other vascular plants, the dominant phase of the life cycle is the sporophyte. The gametophyte phase is small and inconspicuous. • A seed is basically an (young sporophyte) packaged in a protective coat with a supply of nutrients. Seeds are much less vulnerable to unfavorable environmental conditions, and they can remain dormant for extended periods of time without germinating. • In seed plants, the gametophyte has become even more reduced -- often tiny -- and cannot perform photosynthesis on its own. It is Fern gametophyte therefore completely dependent on the sporophyte phase.

• Seed plants have undergone even more extensive specialization of tissues and structures, including: Fern sporophyte Meristem , where growth occurs Surface tissues (e.g. ) for protection On the undersides of fern leaves are More specialized vascular tissues that can transport water and clusters of sporangia called sori nutrients to great heights, and are also used as support (singular: )

“GYMNOSPERMS”: Basal Lineages and Conifers CONIFERS (Gymnosperms): , , firs, cedars, and others • Are not monophyletic • Have unique evergreen leaves commonly called needles • Includes basal lineages that were once dominant and widespread, • Have large female cones and small male cones that produce such as and ginkgos (both still extant) haploid F. megaspores and M. microspores, respectively

Ginkgo biloba A or “sago palm”

3 By this point in plant evolution, the gametophytes have become THE EVOLUTION OF THE highly specialized reproductive structures and cannot live alone • Up to this point, no plants we have discussed have flowers Female gametophytes exist in ovules within a female cone. • A flower is a unique reproductive structure totally different from the cone of a . Its parts are made up of modified Male gametophytes exist as individual pollen grains. leaves, and in fact are homologous to leaves. Conifers are pollinated. • In flowering plants, female gametophytes are completely encased When pollen reaches an ovule, within ovaries that are encased in carpels. a pollen tube grows out of it, • Male gametophytes are highly reduced pollen grains fertilization occurs, an embryo • Fertilization occurs through the aid of specialized flower structures develops, and the ovule is including male stamens and female pistils. as a seed.

Angiosperms have become the most diverse plants on There are over 250,000 known of angiosperms, with new species being discovered all the time.

Why are angiosperms the most diverse plants on Earth?

• Coevolution with (and other kinds of) pollinators • Coevolution with that eat them (evolutionary arms ) • Better vascular systems allow more rapid movement of fluids • Seeds dispersed by animals that eat their • Seeds are highly protected and can remain dormant • Deciduous lifestyles allow seasonality

In short, there are likely to have been many diversifying adaptive during the evolutionary history of angiosperms

4 Our Cousins the Fungi

• Fungi and animals are more closely related to one another than either group is to plants. Why plants are required by other : • This has been determined through molecular phylogenetic analyses.

• Plants produce the that other Eukaryotes need Green Plants Animals Fungi • Plants live symbiotically with nitrogen-fixing and are the first that assimilate fixed nitrogen • Plants form the basis of chains within all The of fungi and animals is called the

5 GENERAL CHARACTERISTICS OF FUNGI Basic Fungal

Fungal cells are organized into tube-like filaments called hyphae. • Multicellular or eukaryotes • walls contains the (what else has chitin?) • Heterotrophic, and tend to be parasites or saprophytes • Feeding is through external and absorption • Many symbioses with plants and animals are known • Two life phases: and reproductive • No roots, stems, leaves, vascular system, or photosynthesis Hyphae are surrounded by a , and grow from the tips. • is both sexual and asexual, even in the same species • Relatively little tissue differentiation or specialization

Basic Fungal Anatomy Basic Fungal Anatomy

The hyphae are organized into a branching mass called the During the reproductive phase, most fungi generate -producing bodies called sporocarps. A known example is the .

The mycelium represents the dominant somatic form of fungi: It grows and feeds as a spreading, branching network of hyphae. Mycelial masses can be ancient and enormous. A single mycelium in covers over 2000 acres mycelia on a Douglas fir tree and is over 2000 years old!

6 Three main fungal groups (Zygomycetes)

Classification is largely based on how they reproduce. • Sporangia on stalks • During sexual phase, Zygomycota (Zygomycetes and Trichomycetes) two hyphae of different “conjugation fungi” types come black together to form a zygosporangium (Ascomycetes, including ) between them “sac fungi”

Basidiomycota (Basidiomycetes) “club fungi”, including common gilled

Exploding shotgun

ASCOMYCOTA (Ascomycetes, “sac fungi”) (Basidiomycetes) • Sac-like cells called asci “club fungi” (sing. ) each cup fungus contain 8 • Reproductive structures • Most asci are produced in structures called basidia usually called form 4 • Most fungi involved in • Fruiting bodies symbioses are (sporocarps) are made of ascomycetes hyphae. One example is penicilli a gilled mushroom. • Ascomycetes important n to include those • Other basidiomycetes that produce include the plant such as ; yeasts used in baking and fungi and ; and edibles such as morels morel

7 And now it’s time for some famous fungal stories

• Weird things fungi do

• Symbioses involving fungi

• Fungi significant to humans

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8 Some fungi are bioluminescent -- they glow in the dark! trapping Chemical glowing may attract insects to aid in spore dispersal Or, it may facilitate DNA repair, or oxygen detoxification are tiny abundant in the soil.

Some fungi form loops and snares with their hyphae, and when a nematode crawls through, the snare tightens and traps the

Like , nematode trapping has evolved multiple independently in the Fungi

Some Ascomycota are obligate pathogens of insects Some Zygomycota are predators or pathogens of for example, the

A fly parasitized by , surrounded by the released spores. caught by “lethal lollipops” of Behavioral Asian have long fungus modification in a ingested caterpillar fungus for its and stimulating properties. In the 1993 infected with Olympics, the Chinese women’s aids track team attributed their huge spore dispersal success to Cordyceps.

9 Flower • Leafcutter of the genus live in intimate with Basidiomycete mycelia that cannot live without the ants. The basidiomycete rust • Different species of ants tend different fungus monoica species of fungi. is a of mustard plants. It inhibits the • have a similar fungal symbiosis formation of flowers in the plant, and instead causes the growth of a yellow “pseudoflower” from the plant’s leaves. This structure fools insects, and by attracting them helps complete the life cycle of the fungus.

Some mushrooms produce mild that are potent Many traditional religions worldwide employ the use of hallucinogenic (or entheogenic) mushrooms for spiritual and religious purposes. A famous example is the Teonanacatl (“flesh of the gods”) used in and Central America, and dating back to the time of the Mayans. These mushrooms were “rediscovered” by Western scientists who visited Mexico in the 1940’s. mushrooms are now used recreationally around the world, but as hallucinogens, their possession is illegal in many countries including the U.S.

Psilocybe sp. Mushroom Maria Sabina, a fetish stone famous Mexican shaman and healer

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