Biol 212- Raven Chap. 12: Systematics: The Science Of Biological Diversity

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define systematics?

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the scientific study of biological diversity and its evolutionary history

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define taxonomy?

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the identification, naming, and classifying of species.

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Who is known as the father of botany?

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Theophrastus (370-285 B.C.)

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Phylogenetic tree:

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depict the genealogic relationships between taxa as hypothesized by a particular investigator.

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monophyletic:

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(of a group of orgnaisms) descended from a common ancestor or ancestral group, especially one not shared with any other group.

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polyphyletic:

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(of a group of organisms) derived from more than one common evolutionary ancestor or ancestral group.

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paraphyletic:

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group contains its last common ancestor but does not contain all the descendants of that ancestor or ancestral group, but not including all the descendant groups.

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homologous:

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structures which have a common origin but not necessarily a common function.

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analogous:

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structures from the result of convergent evolution. Structures with similar functions and superficial appearances but have an entirely different evolutionary background.

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Cladistics:

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- most widely used method of classifying organisms today

- a form of phylogenetic analysis that explicitly seeks to understand phylogenetic relationships

- focuses on the branching of one lineage from another in the course of evolution.

- attempts to ID monophyletic groups (clades)

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Cladogram:

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provides a graphical representation of a working model (hypothesis) of the phylogenetic relationships of a group of organisms.

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Principle of parsimony:

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- fundamental principle of cladistics

- cladogram should be constructed in the simplest, least complicated and most efficient way

- preferred to have more statements of homology and fewest of analogy.

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molecular clock:

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uses the rate at which proteins (nucleic acids) shared by different groups of organisms changed over time as an indication of when those groups diverged from a common ancestor.

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serial endosymbiotic theory:

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both mitochondria and chlorplast are believed to be the descendants of bacteria that were taken up and adopted by some ancient host cell.

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endosymbionts:

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organism that lives within another, dissimilar organism.

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Phagocyte:

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"eating cell"

a cell capable of engulfing large particles such as bacteria.

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Origin of a photosynthetic eukaryotic cell from a heterotrophic prokaryote

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a) most prokaryotes contain a rigid cell wall, initial step in the transformation was a loss of the prokaryote's ability to form a cell wall
b)/c) now has ability to increase in size, change shape, engulf extracellular objects by infolding of the plasma membrane (endocytosis), resulting in the formation of endocytic vesicles.
d)/e) internalization of a patch of the plasma membrane to which DNA was attached was the probable precursor of the nucleus. increased quantity of DNA. Cytoskeleton developed to provide inner support for the wall-less cell.
f) mitochondria had their origin as bacterial endosymbionts, which ultimately transferred most of their DNA to the host's nucleus.
g) chloroplasts also are descendants of bacteria.

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Some characteristics of plants:

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- multicellular

- composed of eukaryotic cells that contain vacuoles and are surrounded by cell walls that contain cellulose.

- get nutrition through photosynthesis.

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describe the reproduction in plants:

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reproduction in plants is primarily sexual, with cycles of alternating haploid and diploid generations.

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gametophyte:

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the haploid, gamete-producing generation in plants.

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sporophyte:

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the diploid, spore-producing generation in plants.

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What may be the reason that the sporophyte is the larger,complex, nutritionally independent generation in vascular plants:

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Diploidy permits the storage of more genetic information generation in vascular plants.