THE PLANTS

Supergroup Plantae

• Original photosynthetic symbionts

• Includes the red algae and the green plants

• All with somewhat simple walls

Eukaryotic Domains

Green Plants

• Chlorophylls a and b• Walls of cellulose• Store starch

Generalized plant life history

Earliest Systems for Plants

• Mostly defined functionally by foragers, farmers, and physicians

• Still used in terms like weed, fruit (non-technical usage), herb, and vegetable

Illustration of an early herbal, De Materia Medica (~50-70 C.E.) by Dioscoides

Theophrastos of Lesbos• Successor to Aristotle and

developed his philosophy in many areas.

• Developed system of plants in parallel with Aristotle’s system on animals

• Structure of plants– Herbs– Shrubs– Trees

c. 371-287 B.C.E., Athens

Karl von LinnéCarolus Linnaeus (1707-1778)

• Linne is reference to a large lime tree near his ancestral home

• Latinized his name to Carolus Linnaeus

• Created a system on plants using the sex organs as a means of classification

• Species Plantarum (1753) is the starting point for all plant taxonomy

Key to the sexual system from the 10th edition (1758) of Systema Naturae

Modern Systems based on Morphology

• Unified botanical information for North America

Gray and Gleason• Asa Gray (1810-1888)• Univ of Michigan and Harvard• Met Darwin at Kew through

Hooker• Manual of Botany a standard for

100 years

• Henry Gleason (1882-1975)• Univ Michigan, Univ Illinois, and

New York Botanical Garden• Revised Gray’s Manual

Molecular Phylogenetics of Plants• PhyloCode (introduced in 1983)• American Phylogeny Group

(also called Angiosperm Phylogeny Group, first released 1991).

• Walter Judd (1951- )• Univ of Florida• Plant Systematics, a

Phylogenetic Approach

Green Plants

MAJOR CLADES OF THE GREEN PLANTS. This system reflects all of these changes in the taxonomy of the Viridiplantae with two subkingdoms: Chlorobionta and Streptobionta. See the Tree of Life Project and Palmer et al. (2004) for the consensus view of the molecular/ ultrastructural relationships between the higher taxa of the green plants.CH = Chlorobiont CladeST = Streptobiont CladeEM = EmbryophytesVP = Vascular PlantsSP = Seed Plants

Green algal diversity

Bryophytes

Tracheophytes

• Plants have vascular tissue– Xylem– Phloem

• Usually with stems, roots, and leaves

Ferns

The Seed

Conifers and other Gymnosperms

Flowering Plants• Contain flowers• Fruit is derived from the ovulary of the flower

MAJOR CLADES OF THE FLOWERING PLANTS1. The Flowering Plants2. The Basal Families3. Plicate Flowering Plants4. Magnoliids + Monocots5. Magnoliids6. Monocots7. Dicots8. Basal Dicots9. Eudicots

Flower

Placement of ovulary

Major Types of Flowering Plants

• Primitive Dicots• Magnolias and their relatives• Monocots• Derived Dicots

Primitive Dicots

Water Lilies Amborella, sister to all other living flowering plants

Magnolias and their Relatives

Magnolia flower Avacado

Monocots

Wheat

Orchid

TABLE 1. Important grass grain plants of the world, their generic names, and the regions of the Earth where the plants were domesticated. Much of this information came from Glemin and Bataillon (2009).

GRAIN GENERIC NAME REGION OF DOMESTICATION

Rice (Figure 25) Oryza AsiaWheat (Figure 26) Triticum Middle EastMaize (corn; Figure 27) Zea Central AmericaBarley Hordeum Middle EastPearl Millet Pennisetum South AfricaFoxtail Millet Setaria East AsiaProso Millet Panicum AsiaFinger Millet Eleusine EthiopiaRye Secale TurkeyOats Avena Middle EastSorghum (milo) Sorghum Northern Africa

Derived Dicots

Flowers –large and small

Wolffia in flower, floating plant

Rafflesia, largest flower, related to euphorbias and parasitic on vines of SE Asia

Amorphophallus titanum, largest unbranched inflorescence, an aroid.

Arrangements of flowers

Largest Inflorescence

Types of fruits

Major Events in Plant Evolution

• Appearance of land plants initially limited to mosses and relatives during Ordovician Period (~470-440 mya) based on fossil spores.

• Plants restricted to lowlands and wet areas of temperate to tropical latitudes.

Mosses growing in a Scotland bog, their success related to symbioses with fungi. Likely, this was true at the time of the earliest emergence. (David Beerling, University of Sheffield)

Life on Land

Advantages• Unfiltered light• Atmosphere larger

reservoir of CO2 • Initially, fewer predators?

Disadvantages• Exposure to UV light• Need for water storage and

uptake• Need for photosynthate

used for support

Major Events in Plant Evolution• Vascular tissue• Shift to dominance of

spore-producing portion of life cycle

Restoration of Cooksonia from Silurian

Vascular tissue in stem of Rhynia, lower Devonian

Telome Theory

Walter Max Zimmermann; 1892-1980, Germany

Major Events in Plant Evolution

Late Devonian Pennsylvanian

Major Events in Plant EvolutionThe Seed

Major Events in Plant Evolution

Major Events in Plant Evolution

Major Events in Plant Evolution

These are from the lower Cretaceous, but flowering plant pollen has been found in strata 100 my earlier.

Major Events in Plant Evolution

Wasp attempting to copulate with an orchid

The Bee Orchid