BIOLOGY 3404FEVOLUTION OF PLANTS

Fall 2008http://instruct.uwo.ca/biolog

y/3404f

Dr. R. Greg ThornDepartment of Biology,

UWO

TODAY’S OUTLINE

• Course introduction and logistics– Announcements and Contacts– Grading, Lectures, Labs, Texts

• Introducing your lecturer• What organisms are we going to study?

• What is systematics?

GRADING

• Assignments 1-3 5% each (Sep 23, Oct 7, Oct 28)• Essay 15% Tue Nov 18• Midterm Exam 25% 1h Tue Oct 21• Final Lab Exam 15% Mon Dec 1 (in lab)• Final Exam 30% 3h (TBA)

Lectures, Labs & Text

• Lectures emphasize diversity, evolutionary relationships and importance

• Labs emphasize morphology and recognition• The required text (to be supplemented by important

journal articles) supplies a good synthesis: Raven, Evert & Eichorn. 2005. Biology of Plants, 7th ed. W.H. Freeman, New York. We will use Chapters 1 and 11-20, plus supplemental readings to be provided. [Chapters 13 and 14 include many non-photosynthetic organisms that will not be covered in detail.]

Tentative Schedule (synopsis)

• Photosynthetic prokaryotes, protists, fungi, and bryophytes (Chapters [1, 11, 12],13-16)

• Midterm• Vascular plants: pteridophytes, gymnosperms, angiosperms (Ch. 17-20)

• Final exam

WHAT ORGANISMS DO WE STUDY?

• DOMAIN ARCHAEA (= ARCHAEBACTERIA)

• DOMAIN BACTERIA (= EUBACTERIA)

• DOMAIN EUKARYOTA– KINGDOM PROTISTA– KINGDOM FUNGI (only their symbionts

are photosynthetic)– KINGDOM PLANTAE– KINGDOM ANIMALIA (only their

symbionts are photosynthetic)

Prokaryotes• Domain Archaea

– Halophiles: Halobacterium (rhodopsin)– Methanogens– Thermophiles

• Tremendous genetic diversity• Many are now being found in environments that

are not extreme - e.g., in soil, root surfaces, etc.For a moderately modern taxonomic treatment, see

Bergey’s Manual (in library, or online at http://www.bergeys.org)

Prokaryotes II• Domain Bacteria [some examples]

• Phylum Proteobacteria: includes Rhizobium in N2-fixing associations (nodules) with legumes, and Agrobacterium of plant galls

• Phylum Cyanobcteria: Nostoc, in many lichens, and Anabaena, found in the water-fern Azolla

•Phylum Actinobacteria: Frankia, in N2-fixing associations with non-legumes

• More genetic diversity than ALL eukaryotes

The Prokaryote origins of eukaryotes and photosynthesis

• Purple and green bacteria (photoautotrophic; not closely related)

• Sources of mitochondria (purple nonsulfur) and photosynthesis in all plants, algae and cyanobacteria (PSII from purple sulfur and PSI from green sulfur)

• Chloroplasts arose by endosymbiosis of a cyanobacterium into an early eukaryote

KINGDOM PROTISTA

• Includes protists that are fungus-like ("water molds" and "slime molds”), plant-like ("algae”), and animal-like ("protozoa")

• [Fungus-like: Myxomycota, Dictyosteliomycota, Oomycota, etc. – see BIO 3218b]

• Algae: Euglenophyta, Cryptophyta, Rhodophyta, Dinophyta, Haptophyta, Chrysophyta, Bacillariophyta, Phaeophyta, Chlorophyta

• [Protozoa: Not covered – see BIO 2240F/G]

KINGDOM FUNGI• [Phylum Chytridiomycota (water moulds and

rumen fungi)]• Phylum Glomeromycota (the mycobionts of

endomycorrhizae)• [Phylum Zygomycota (sugar moulds or bread

moulds)]• Phylum Ascomycota (includes the mycobionts of

most lichens; others are saprotrophs or pathogens)• Phylum Basidiomycota (includes the mycobionts

of most ectomycorrhizae; a few others are mycobionts of basidiolichens; others are saprotrophs or pathogens)

KINGDOM PLANTAE• Phylum Bryophyta (mosses)• Phylum Hepatophyta (liverworts)• Phylum Anthocerophyta (hornworts)• [Phylum Zosterophyllophyta]• [Phylum Rhyniophyta]• [Phylum Trimerophyta]• Phylum Psilophyta (psilopsids)• Phylum Lycophyta (clubmosses, spikemosses &

quillworts)

• [xx] = dead

PLANTAE part II• Phylum Equisetophyta (= Sphenophyta) (horsetails)• Phylum Pterophyta (= Pteridophyta, Polypodiophyta,

etc.) (ferns)• [Phylum Pteridospermophyta (seed ferns)]• Phylum Cycadophyta (cycads)• Phylum Ginkgophyta (ginkgo)• Phylum Coniferophyta (conifers)• Phylum Gnetophyta (gnetophytes)• Phylum Anthophyta (Angiosperms, "Flowering

Plants")

TAXONOMY & SYSTEMATICS• Both have to do with classifying and naming organisms

• Taxonomy is now often regarded as the poor cousin or antiquated version of systematics – you won’t find many university departments of Plant Taxonomy, but you might find a few university courses with that name

• Folk taxonomies – all around the world, people have recognized and named the organisms that are considered useful or dangerous, and often grouped them in some way

TAXONOMY

• Gk taxis – arrangement + nomos – management/law

• Webster: the science of classification of objects

• Raven: the science of the classification of organisms

• Judd: Theory and practice of grouping individuals into species, arranging species into larger groups, and giving these groups names, thus producing a classification

SYSTEMATICS

• Gk systema – system + atikos – about

• Webster: the science or method of classifying, especially taxonomy

• Raven: Scientific study of the kinds of organisms and the relationships between them

• Judd: The science of organismal diversity, frequently used in a sense roughly equivalent to taxonomy

TAXONOMY vs SYSTEMATICS• If there is any difference, it is that systematics (post-Darwin) is concerned with creating a classification that reflects evolutionary relationships. Taxonomists have in the past frequently created classifications of convenience, consisting of easy-to-recognize groups based on patterns of overall similarity

• Since ~no taxonomists now classify in the absence of evolutionary evidence, the two terms are essentially equal

Why base classification on evolution?

• Knowing the identity of something (or someone) – its name – is potentially informative of what it does, where it lives, etc., as well as what it looks like

• Because related organisms share many traits (e.g., biochemical pathways, structure, morphology), a classification that is based on evolutionary relationships has potential to be more predictive than one that is not

Next Week• I will be away! • No classes, but lecture material will be posted online

• Evolution • Geological time scale• Readings: Chapters 1, 11, and 12• In Lecture time on Thurs Sep 18 we will take a hike around campus to see “Plants” in the real world. Come dressed for it - rain or shine.

• First lab Sept 22, meet in BGS 3015 at 2:30 p.m.

Assignment #1

• See the web link at http://instruct.uwo.ca/biology/3404f/Lectures.html