Phylogeny of

Green plants “Green (land plants) Chlorophytes


Cuticle Sporopollenin

Ref.4 Ref.6 Ref.7 Pop Quiz

According to the phylogenetic shown in the previous slide, the group “” is:

A. Monophyletic B. Paraphyletic C. Polyphyletic D. I have no idea Phylogeny of Land Plants

Embryophytes (land plants) “” Tracheophytes (vascular plants) Liverworts

in vascular Ref.10 Ref.8 Ref.9



Ref.11 Phylogeny of Tracheophytes

Tracheophytes (vascular plants)

Seed plants (+Angiosperms)

Lycophytes and allies


Ref.14 Ref.13 Ref.16 true Phylogeny of Plants

Seed plants

Gymnosperms Angiosperms


bitegmic Ref.20 Ref.18 Ref.17 reduced

Ref.19 Homework

Integrate the information from the previous slides and draw a tree showing the relationships of the major groups. Also, mark the synapomorphies defining those major monophyletic groups along the branches. Life Cycle: Angiosperm (Flowering plants)

Ref.1 Some Key Concept in Angiosperm Life Cycle

NOTE: definitions used in lectures of this are mainly following the textbook (Judd et al., 2008. Plant systematics: a phylogenetic approach, 3rd ed.)

Meiosis: two-stage nuclear process that reduces the number of a by half (from a diploid cell to 4 haploid daughter cells), followed by production of . : nuclear division that maintains the parental chromosome number for daughter cells; the basis for growth in size and asexual in plants. Fertilization: fusion of the nucleus and the nucleus. (2n): the cell formed by the fusion of the sperm (1n) and egg (1n) at fertilization, germinates to produce a multi-cellular (2n) via mitosis. (1n): the first cell of a gametophyte (1n), product of . Sporophyte (2n): diploid, spore-producing generation of the plant life cycle, produces spores via meiosis in a structure called (plural, sporangia). Gametophyte (1n): Haploid, -producing generation of the plant life cycle; produces via mitosis in specialized structures/ organs—gametangia (male: , produce sperm; female: , produce ) Some Key Concept in Angiosperm Life Cycle (cont.)

Embryo vs. Embryo sac

Embryo (2n): young sporophyte, from the first cell after fertilization (zygote) until of the seed (in seed plants) or emergence from protective gametophytic tissues (other land plants).

Embryo sac (1n): female gametophyte of the angiosperms (flowering plants). Life Cycle: Fern and Fern Allies

Ref.2 Life Cycle: Bryophytes

Ref.3 The sporophyte generation is dependent on the photosynthetic gametophyte for nutrition Generalized Life Cycle in Plants

Alternation of generations = cycle between haploid (1n) and diploid (2n) phase

Difference between plants and Animals: meiosis produces gametes directly. Plants: meiosis produces spores (to start gametophyte generation), and mitosis produces gametes. Variation of Life Cycle in Plants

“Bryophytes” (mosses, liverworts, hornworts) - Most of life is in 1n phase, therefore, gametophyte (green leafy base) dominant life cycle; sporophyte (brown stalked /sporangium) dependent on gametophyte (grows out of gametophyte and gets all nutrition from gametophyte). Sporophyte produces spores that land on ground & germinate into .

Ferns and fern allies - sporophyte dominant; gametophyte free-living, but small and short-lived. Leaves = sporophyte, free-living. Spores germinate from sporangia on underside of leaves (sori) and produce small, green, free-living heart-shaped gametophyte on ground. Gametophyte with separate structures that produce egg & sperm; lives ~1 year, reproduces, then dies. Sporophyte dominant life cycle: lives longer and larger and reproduces many years. Seed plants (Angiosperms and Gymnosperms) - sporophyte dominant; gametophyte dependent on sporophyte and very reduced and short-lived. in pollen-bearing structures (pollen cones or anthers) that produce male gametophyte, short-lived and inside the pollen grain, which consists of 2-3 cells, one cell becomes sperm. Megasporangia in ovules that produce female gametophyte in cone (“gymnosperms”) or (angiosperms) and produces the egg. Spores grow into pretty small gametophytes which are contained within the parent plant (inside cones or ). vs. Fertilization

Distinction and Relationship of Pollination and Fertilization Pollination: transference of pollen from the anther to the .

Fertilization: fusion of the sperm nucleus and egg nucleus.

Pollination occurs only in seed plants; Fertilization occurs in all sexually Reproducing organisms.

In plants, pollination must occur before fertilization! (Without pollination, fertilization can not take place. ) Pollination Syndromes

“Sexual Encounters of the Floral Kind” Handout to accompany film – Biology 117/317 Pollination syndromes

Wind Pollination: 1) flowers appear before leaves are out 2) large number of flowers (especially males), often in catkins 3) individual flowers small and inconspicuous - without parts for attraction 4) Big produce lots of pollen 5) Stigmas large and plumose or roughened (papillate) to catch pollen 6) Ratio of pollen to ovules VERY HIGH (up to 6,000 to 1)

Many different kinds of insects function as ; often these involve very different floral characteristics: Bees, butterflies, etc.: 1) flowers showy, with brightly colored 2) flowers usually with some food reward, two common ones are: pollen - rich reward - rich in (e.g., amino acids and ) 3) flowers often with strong favorable scent during the day 4) flowers often with ultraviolet markings visible only to the insects (not to humans) Pollination Syndromes (cont.)

Moths: 1) flowers often white 2) flowers open and scent released in the evening or at night 3) nectar reward 4) flowers often long and tubular to limit access only to long tongued moths

Carrion flies (Blowflies): 1) flowers purple or brown or greenish-brown 2) flowers often close to the ground 3) scent strong and foul (like dead )

“Buzz” pollination by bees: 1) no nectar reward (pollen sole reward) 2) connivent anthers (anthers held together) at center of flower 3) anthers opening by terminal pores; pollen shakes out when the bee buzzes the flower

Birds often pollinate flowers, too: Hummingbirds (found in North and South America only): 1) flowers with long tubular corollas 2) flowers usually red 3) nectar reward in large quantity, rich in sugars (few other nutrients) 4) flowers often dangle away from plant so that bird can reach it while hovering

In other parts of the world different birds, including Honeycreepers (Hawaii), Honeyeaters (Australia) and Sunbirds (S. Africa) act as pollinators. Flowers adapted to these birds differ from those adapted for hummingbirds by having a “landing platform” for the birds to perch on, because they cannot hover. The flowers still have long tubular corollas and lots of -rich nectar. Image Source

Ref.1 http://8e.devbio.com/image.php?id=525 Ref.2 http://8e.devbio.com/image.php?id=524 Ref.3 http://8e.devbio.com/image.php?id=523 Ref.4 http://content.answers.com/main/content/wp/en-commons/thumb/c/c9/250px-Haeckel_Siphoneae.jpg Ref.5 http://www.vcbio.science.ru.nl/images/stemgrowth/SGembryo-apicalmeristem.jpg Ref.6 http://www.uni-muenster.de/GeoPalaeontologie/Palaeo/Palbot/cut1a.jpg Ref.7 http://en.wikivisual.com/images/a/a4/Misc_pollen.jpg Ref.8 http://www.hiddenforest.co.nz/bryophytes/mosses/familys/racopilaceae/images/racop01bt.jpg Ref.9 http://ux.brookdalecc.edu/fac/biology/lab/102/images/liverwort1.jpg Ref.10 http://www.cartage.org.lb/en/themes/Sciences/BotanicalSciences/ClassificationPlants/Cryptogamia/Bryophyta/Nonvascular/hornwort1.JPG Ref.11 http://www.freewebs.com/jdingfel/Stomata.jpg Ref.12 http://f030091.ffpri.affrc.go.jp/image/OM_code_E/60.Tracheids.gif Ref.13 http://media-2.web.britannica.com/.../04/7604-004.jpg Ref.14 http://static.howstuffworks.com/gif/define-ferns-1.jpg Ref.15 http://home.pacbell.net/kenww/my_iris/other/I_foetidissima_seeds-web.jpg Ref.16 http://www.bioquest.org/scope/projectfiles/PollenMixb.jpg Ref.17 http://www.icbgpanama.org/website/gall_pictures/Gnetumfrutos.jpg Ref.18 http://www.dickcontino.com/images/ginkgo.jpg Ref.19 http://www.emc.maricopa.edu/faculty/farabee/BIOBK/fertil1.gif Ref.20 http://web.gccaz.edu/~lsola/Flower/capsella3.jpg