Announcements

Lab Quiz #1 on Monday: (30pts) conifers + cones, vegetative morphology

Study: Display case outside HCK 132 with labeled conifers

Movie: Sexual Encounters of the Floral Kind

Intro to Keying/Greenhouse tours: dichotomous keys - progressive series of paired, alternative statements that lead to the identification of an organism

Review of the previous lecture

Gr. Morph = form (structure, size, shape) + logy = study of

Vegetative morphology: any part of the plant involved in growth, development, photosynthesis, support, etc., but NOT involved in sexual reproduction

Reproductive morphology: any portion of the plant involved in or a direct product of sexual reproduction

Ovary position

Correction: perigynous

Green plants (Kindgom Plantae)

“Green algae”

Green plants

Live

rwor

ts M

osse

s H

ornw

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Lyco

phyt

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Fern

s

Gymnosperms Angiosperms Seed plants

Tracheophytes (vascular plants) Bryophytes

Embryophytes (land plants)

Phylogeny of Green Plants

Embryophytes (land plants)

“Green algae” Green plants

Embryo

http://www.vcbio.science.ru.nl/

Sporopollenin

http://en.wikivisual.com/

Cuticle

http://www.uni-muenster.de/GeoPalaeontologie/Palaeo/Palbot/cut1a.jpg

http://www.botany.wisc.edu/courses/botany_330/

Phylogeny of Green Plants

Embryophytes (land plants)

“Green algae” Green plants

http://www.botany.wisc.edu/courses/botany_330/

Embryo

http://www.vcbio.science.ru.nl/

Sporopollenin

http://en.wikivisual.com/

Cuticle

http://www.uni-muenster.de/GeoPalaeontologie/Palaeo/Palbot/cut1a.jpg

Pop Quiz

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

A.  Monophyletic B.  Paraphyletic C.  Polyphyletic D.  I have no idea

http://ux.brookdalecc.edu/fac/biology/lab/102/images/liverwort1.jpg http://www.hiddenforest.co.nz/bryophytes/mosses/familys/racopilaceae/images/racop01bt.jpg http://www.cartage.org.lb/en/themes/Sciences/BotanicalSciences/ClassificationPlants/Cryptogamia/Bryophyta/Nonvascular/hornwort1.JPG

Tracheophytes (vascular plants)

“Bryophytes”

Phylogeny of Land Plants

Embryophytes (land plants)

stomata

tracheids

http://www.freewebs.com/jdingfel/Stomata.jpg

http://f030091.ffpri.affrc.go.jp/image/OM_code_E/60.Tracheids.gif

Phylogeny of Tracheophytes

Tracheophytes (vascular plants)

Seed plants (Gymnosperms+Angiosperms)

true leaves

seeds

pollen

Textbook DVD WSJ

Textbook DVD WSJ

http://home.pacbell.net/kenww/my_iris/other/I_foetidissima_seeds-web.jpg

http://www.bioquest.org/scope/projectfiles/PollenMixb.jpg

Phylogeny of Seed Plants

Angiosperms

Seed plants

Gymnosperms

reduced female gametophyte

endosperm flowers

carpel

bitegmic ovules Textbook DVD WSJ

http://www.dickcontino.com/images/ginkgo.jpg http://www.emc.maricopa.edu/faculty/farabee/BIOBK/fertil1.gif

http://web.gccaz.edu/~lsola/Flower/capsella3.jpg

Generalized Life Cycle in Plants vs. Animals

What’s the difference between plants and animals?

Generalized Life Cycle in Plants

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

http://en.wikipedia.org/wiki/Alternation_of_generations

Life Cycle: angiosperms (flowering plants)

http://8e.devbio.com/image.php?id=525

Life Cycle: ferns and fern allies

http://8e.devbio.com/image.php?id=524

Life cycle: bryophytes

Ref.3 The sporophyte generation is dependent on the photosynthetic gametophyte for nutrition

Variation of life cycle in plants

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

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 gametophytes 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. Microsporangia 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 ovary

(angiosperms) and produces the egg. Spores grow into pretty small gametophytes which are contained within the parent plant (inside cones or

flower).

embryo vs. embryo sac

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

Embryo sac (1n): female gametophyte of the angiosperms (flowering plants).

Some key terms in the angiosperm life cycle

Some key terms in the plant life cycle

Meiosis = reductive nuclear division process that reduces the chromosome number of a cell by half (from a diploid cell to 4 haploid daughter cells).

Mitosis = nuclear division that maintains the parental chromosome number for daughter cells; the basis for growth in size and asexual reproduction in plants.

Fertilization = fusion of the sperm nucleus and the egg nucleus to form a zygote.

Zygote (2n) = the cell formed by fusion of the gametes (sperm [1n] and egg [1n]) at fertilization; embryo.

Spore (1n) = the first cell of the gametophyte generation; product of meiosis.

Sporophyte (2n) = diploid, spore-producing generation of the plant life cycle, that produces structures called sporangia (singular, sporangium).

Gametophyte (1n) = haploid, gamete-producing generation of the plant life cycle, that produces structures/sex organs—gametangia (male: antheridium, produce sperm; female: archegonium, produce eggs).

Seed plants (angiosperms and gymnosperms) – Sporophyte independent and dominant. Gametophyte dependent on sporophyte and very reduced and short-lived.

Microsporangia in pollen-bearing structures that produce male gametophytes; in pollen cones (gymnosperms) or anthers (angiosperms). Male gametophytes = short-lived and inside the pollen grain;

2-3-celled, 1 cell becomes 2 sperm.

Megasporangia in ovules that produce female gametophytes, which produce eggs; in cones (gymnosperms) or ovaries (angiosperms).

Spores grow into small gametophytes which are contained within the parent plant (inside cones or flower).

Some key terms in the seed plant life cycle

Which comes first: pollination or fertilization?

Pollination = transfer of pollen from anther to stigma.

Fertilization = fusion of sperm nucleus and egg nucleus.

Pollination occurs only in seed plants! Fertilization occurs in all sexually reproducing organisms.

In seed plants, pollination must occur before fertilization!

Summarize the synapomorphies for major groups of land plants

“Green algae”

Green plants

Live

rwor

ts M

osse

s H

ornw

orts

Lyco

phyt

es

Fern

s

Gymnosperms Angiosperms Seed plants

Tracheophytes (vascular plants) Bryophytes

Embryophytes (land plants)

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

Pollination syndromes

Wind Pollination:1) flowers appear before leaves are out2) large number of flowers (especially males), often in catkins3) individual flowers small and inconspicuous - without parts for attraction4) Big stamens produce lots of pollen5) Stigmas large and plumose or roughened (papillate) to catch pollen6) Ratio of pollen to ovules VERY HIGH (up to 6,000 to 1)

Many different kinds of insects function as pollinators; often these involve very differentfloral characteristics:

Bees, butterflies, etc.:1) flowers showy, with brightly colored petals2) flowers usually with some food reward, two common ones are:

pollen - protein rich rewardnectar - rich in nutrients (e.g., amino acids and sugars)

3) flowers often with strong favorable scent during the day4) flowers often with ultraviolet markings visible only to the insects (not to humans)

Pollination Syndromes

Moths:1) flowers often white2) flowers open and scent released in the evening or at night3) nectar reward4) flowers often long and tubular to limit access only to long tongued moths

Carrion flies (Blowflies):1) flowers purple or brown or greenish-brown2) flowers often close to the ground3) scent strong and foul (like dead animal)

“Buzz” pollination by bees:1) no nectar reward (pollen sole reward)2) connivent anthers (anthers held together) at center of flower3) 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 corollas2) flowers usually red3) 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 fromthose adapted for hummingbirds by having a “landing platform” for the birds to perch on, becausethey cannot hover. The flowers still have long tubular corollas and lots of sugar-rich nectar.

Pollination Syndromes