Biological Diversity and Systematics EEOB 405.01 - Spring Quarter 2002 Weeks 8-11: Fungi and Plants Instructor: Dr. Andrea D. Wolfe, 326 B & Z, 1735 Neil.

Biological Diversity and Systematics

EEOB 405.01 - Spring Quarter 2002

Weeks 8-11: Fungi and Plants 

Instructor: Dr. Andrea D. Wolfe, 326 B & Z, 1735 Neil Ave, 292-0267, [email protected]

Office Hours: by appointment (email works well for contacting me)

Textbook: Selected Chapters from Botany, 2nd Ed. (1998) by Moore, Clark, and Vodopich

Course goals: Understand the broad features of evolution within the fungi and selected taxa of diverse photosynthetic organisms. This will include knowledge of patterns of descent (phylogenies) and the important traits that document evolutionary trends within these groups. We will also consider major features of the ecology of these organisms and their

economic importance.

Outline Lecture 1: Plant evolution and phylogeny.

Readings: Chapters 23 & 24 in Moore et al. 

A. Systems of classification.

1. Rise of cladistics, based on formal analysis of changes in characters over time and across groups.

a. Evolutionary hypotheses can be formulated and tested.

2. Five kingdom classification by Margulis and Schwartz

a. Based on traditional methods of systematics (1988).

b. Modern phylogeny of life based on RNA.

3. Traditionally, all organisms containing chlorophyll a were put in ‘plant kingdom’.

a. Our treatment of organisms will span three kingdoms.

B. Overview of groups we will consider.

1. Fungi, Algae, Mosses, Ferns, Conifes, Flowering plants.

C. Some important features of evolution in flowering plants.

1. Limited gene dispersal distances via pollen flow.

2. Hybridization as a route to speciation.

a. Importance of polyploidy.

Reconstructing relationships

• Intuitive classifications

• Cladistics– Direction is important– Indicated by shared derived characters

(synapomorphies)

Cladograms, characters

Spines Stipules Compound leavesRose 1 1 1Catbriar 1 0 0Pea 0 1 1

Pine 0 0 0

Spines

RCP

Pine

Stipules

Pine

RC P

Compound lvs.

Pine

RC P

Parsimony

How do we choose which pattern to accept?

RCP

PinePine

RC P

StipulesCompound lvs.Spines

StipulesCompound lvs.

Spines

Steps = 4 Steps = 5

Monophyly, paraphyly

Genus A -- monophyleticGenus B -- paraphyletic

The Key: a common ancestor and its descendants

A basic cladogram

Hypothetical ancestors

A Cladogram is not exactly a Phylogenetic Tree

Cladogram:

A network of characters and taxaNo real ancestors (nodes are hypothetical)

Phylogenetic tree:

Can show ancestors and relationships among all units

A Cladogram is not exactly a Phylogenetic Tree

A B C D E

A

B

C

D E

A Cladogram is not exactly a Phylogenetic Tree

Five Kindoms, of Margulis and Schwartz (1988)

A traditional, non-cladistic phylogeny of plants (Cronquist, ~1950)

A modern cladistic phylogeny of life, based on RNA gene sequences.

Alternation of GenerationsDoes the organism have two distinct ploidy phases? -- Gametes do not count -- Phases defined by meiosis and recombination -- Gametophyte and sporophyte

Cladophora

Fungi

Cup fungi

‘Mushrooms’

Yeasts

Algae

BrownRed

Green

Flowering plants

What is a species?

Biological Species Concept

Morphological Species Concept

Genetic Species Concept

Paleontological Species Concept

Evolutionary Species Concept

Modes of speciation in plants

Tulip Tree – Liriodendron tulipifera

Modes of speciation, continued.

Hybridization is relatively common in plants.

What happens during hybridization?

But, many hybrid plants can continue to reproduce vegetatively (asexually).

Chromosome doubling (tetraploid)

Polyploidy can restore fertility by restoring the condition of paired chromosomes.

How can a new, fertile species arise via hybidization?

Polyploidy by non-disjunction of chromosomes (allopolyploidy) is common and relatively easily recognized.

Example of a weird, mutant, polyploid plant: