Variation, Selection & Evolution in Plants
I. Evolution by Natural Selection
A. Charles Darwin, Alfred Russel Wallace
1. What is evolution?
2. What is natural selection?
-Origin of Species (1859)
B. Evidence for Evolution and Natural Selection
1. What is the evidence for evolution?
-Biogeography (Distribution of species)
-not just environment that determines where organisms are found
-natural selection is ongoing: ecotypes in Achillea glandulosa
-molecular biology
C. What is the basis of variation in populations?
1. mutation mutation2 transposons
D. Speciation
How does it come about?
1. Factors that act on a population gene pool
POPULATIONS EVOLVE NOT INDIVIDUALS
Allopatric or geographic speciation
Sympatric or "same place" speciation
Types of Species:
2. Polyploidy (sympatric)
Gamete formation depends on the presence of homologous pairs in meiosis
polyploidy can make "true" hybrids fertile
sunflowers in American west: Helianthus annus X H. petiolaris = H. anomalis
II. Artificial Selection
A. Inbreeding
-"hybrid" strains
B. Asexual reproduction
III. Plant Systematics/Taxonomy
A. Early History
1. Theophrastus (370-287 B.C.)
-Enquiry Into Plants
2. Dioscorides (first century A.D.)
3. The Herbalists (Renaissance)
-Doctrine of Signatures
Hepatica acutiloba; Pulmonaria officinalis; Ranunculus ficaria; Sanguinaria canadensis 1 2
4. Carolus Linneaus (1707-1778)
B. How are plants named?
1. common name
2. scientific name
