Term
|
Definition
| Artificial Sexual System: Classifying according to arrangement & number of stamens and pistils |
|
|
Term
| Old Systems: Bentham & Hooker |
|
Definition
| Natural System: British botanists organized dicots based on order of decreasing fusion of petals |
|
|
Term
|
Definition
| Phylogenetic system: German Botanists Engler & Karl Prantl: organize from simple to complex to demonstrate ancestral relationship, monocots listed before dicots, catkins before dicots, independent origin of monocots & dicots |
|
|
Term
|
Definition
| Phylogenetic System: N. American botanist used various guiding rules or "dicta" to determine level of primitiveness of a group of plants. Organized on position and fusion of ovary and fusion of petals. Magnoliids primitive, basis of contemporary systems. |
|
|
Term
| Contemporary Classification Systems: |
|
Definition
Arthur Cronquist (American)
Amen Takhtajan (Russian)
Robert Throne (American) |
|
|
Term
| Similarities of Contemporary Systems: |
|
Definition
| -Use trends of character evolution as the guidelines in the interpretation of particular relationships-*incorporated evidence from other studies of plants* all are phylogenetic systems*all are similar in principle: dividing flowering plants into monocots and dicots and considering magnolia-like plants primitive |
|
|
Term
| Differences of Contemporary Systems |
|
Definition
| -Differ in methods of evaluating character evolution-*differ in ranks used, names, and composition of categories* |
|
|
Term
| Molecular Phylogeny-based classification -APG system |
|
Definition
| APG SYSTEM: Resulted in world wide collaboration of plant systematists, based on phylogenetic trees derived from molecular data. No formal rank names are given to groups above the orders. Only monophyletic groups are given formal names. |
|
|
Term
| Molecular Phylogeny-based classification - Phylocode |
|
Definition
| alternative to rank-based nomenclature, names only clade. |
|
|
Term
|
Definition
| *big gaps between angiosperms and other living groups of organisms* incomplete angiosperm fossils* Great diversity in angiosperms* Sudden appearance and the abundance of flowering plant fossils in Cretaceous strata |
|
|
Term
| Single Origin of Angiosperms |
|
Definition
| :Vessel elements in xylem* animal-mediated pollination* stigmatic pollen germination* enclosed ovules within an ovary* double fertilization |
|
|
Term
| Angiosperm Evolution: lowland theory |
|
Definition
| Angiospems were not present before the cretaceous*appeared in lowlands (tropics) and radiated rapidly northward |
|
|
Term
| Angiosperm Evolution: Upland theory |
|
Definition
| evolved in tropical upland habitats in the Triassic where preservation of fossils would not be as likely as in lowland basins. Angiosperms were already diversified at the time of the first appearance in the lower cretaceous. |
|
|
Term
| Angiosperm Evolution: Modern Idea |
|
Definition
| Occurred in gondwanaland (australian plate) earlier than the cretaceous* geographically restricted (upland) not radiate until the cretaceous when many of the advanced features of angiosperms evolved. radiation began at low tropical paleoaltitudes, followed by predominantly pole-ward migration |
|
|
Term
| Earliest Angiosperms: Amentiferea Theory |
|
Definition
| Primitive angiosperms are Amentiferea (catkin bearers) |
|
|
Term
| Earliest Angiosperms: Magnoliid theory |
|
Definition
| Primitive angiosperms are magnolia-like, woody, evergreen, w/ simple, alt, reticulate veined leaves. flowers are perfect, showy, acinomorphic, hypogynous, w/ many parts that are free spirally arranged. Pollen monocolpate, nectaries absent. |
|
|
Term
| Possible Precursors of angiosperms |
|
Definition
| *gymnosperms* Cordaites: seed ferns and bennettitales (cycad) are mostly considered. |
|
|
Term
| Closest relatives of angiosperms |
|
Definition
gnetales are closest.
*reduced female gametophyte
*integuments in ovule
*presence of vessels
*reticulate venation
*scaly bracted strobili
*perianth-like female strobilus
*process similar to double fertilization |
|
|
Term
|
Definition
| Amborella, nymphaeales,*gnetales not closest relatives* magnoliids contain most primitive angiosperms* Amborella is the first branching angiosperm. Ancestor may be woody plants without vessels and have medium sized unisexual flowers. |
|
|
