Lecture 18 - 3.Plants - multicellular autotrophs (descent...

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BIOLOGY 1001: LECTURE 18 EVOLUTION OF EUKARYOTES DNA HYBRIDIZATION: comparison of whole genomes of two species by estimating degree of bonding between single-stranded DNA obtained from each species MOLECULAR CLOCK: estimate of time since two species shared a common ancestor based on degree of genetic difference, assuming that rate of change has been constant The prokaryotes belong to two kingdoms: A.ARCHAEBACTERIA - restricted to extreme environments similar to early earth B.EUBACTERIA - all other bacteria, spirochaetes, cyanobacteria, etc. Origins of the endosymbiotic organelles: Mitochondria were free-living aerobic, heterotrophic eubacteria Chloroplasts were free-living autotrophic cyanobacteria The eukaryotes comprise four kingdoms: 1.Protista - eight major taxonomic groups including: a.Protozoa - unicellular heterotrophs b.Eukaryotic algae - unicellular autotrophs c.Slime molds - single/multi-cellular heterotrophs 2.Fungi - multicellular heterotrophs (descent from red algae or slime molds)
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Unformatted text preview: 3.Plants - multicellular autotrophs (descent from green algae) 4.Animals - multicellular heterotrophs (descent from protozoa) AUTOTROPHIC NUTRITION - organism produces its own organic nutrients from sunlight or other inorganic sources EUKARYOTES - Organisms with cells containing a nucleus and organelles HETEROTROPHIC NUTRITION - organism acquires organic nutrients by eating the products of other organisms ORGANELLES - Unit within the cytoplasm of the cell that performs a specialized function A.MITOCHONDRIA - site of cellular respiration B.CHLOROPLAST - site of photosynthesis (conversion of CO 2 and H 2 O to organic compounds by sunlight) PROKARYOTES - Organisms with cells lacking a nucleus SYMBIOSIS - Where two different organisms live in direct contact 1.MUTUALISM: both species benefit 2.COMMENSALISM: one species benefits, the other is unaffected 3.PARASITISM: one species benefits at the other's expense...
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This note was uploaded on 01/20/2010 for the course BIOL 1001 taught by Professor Fall during the Fall '08 term at Minnesota.

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