chapters 14-17. change over time spontaneous generation: living organisms arise from non-living...
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Change over timeSpontaneous Generation: Living organisms
arise from non-living things.Many experiments were conducted to
disprove spontaneous generation.
SCIENTIST DISPUTED THEORY
CONCLUSIONS
Francesco Redi (1600’s)
Maggots come from rotting
meat
Maggots come from eggs laid
by flies
Lazzaro Spallanzani
(1700’s)
Microorganisms come from a
vital force in the air
Microorganisms travel in the air
Louis Pasteur (1800’s)
Boiling destroys air’s vital force
Solid particles in the air transport
microorganisms.
Formation of Simple Organic CompoundsAlexander Oparin, 1923 (H2O, H2, CH4, &
NH3)Formation of Complex Organic Compounds
Amino acids formed chains in early atmosphereConcentration & Enclosure of Organic
CompoundsCoacervates & Microsphere formed
Evolution of Growth, Metabolism, & Reproduction
Approximately 4.6 – 3.5 billion years ago.First organisms – Prokaryotic cellsEukaryotic cells – 1 billion years ago
Endosymbiont Theory – Eukaryotic mitochondria evolved from bacteria & chloroplasts evolved from cyanobacteria.
Dating fossilsCarbon-datingPosition in
sedimentary rockFormation of the
Fossil RecordTypes of fossils:
MoldCastImprint
Common ancestryHawaiian honeycreepers
Homologous structuresSimilar embryologically,
but have different functionsVestigial organs
Functionless partsBiochemistry
Similar biochemical metabolismEmbryological Development
Fish, rabbits, gorilla
Jean Baptiste de Lamarck (1774-1829)Before DarwinInheritance of Acquired Characteristics“If you don’t use it, you lose it”
Natural SelectionOrganisms with favorable variations survive &
reproduce at a higher rate
Variation exists among individuals of a species.
Scarcity of resources in an increasing population will lead to competition
Individuals with advantageous variations are more likely to survive & reproduce.
CONVERGENT
EVOLUTION
DIVERGENT EVOLUTION
Type of Environment
Similar Different
Two or more species
Similar but unrelated
Related but different
Examples Cactus & euphorbia
Red fox & kid fox
The joint change of two or more species in close interaction.
Example: Plants & animals that pollinate them
PopulationAll members of the same species living in a
particular location at the same timeGene Pool
Collection of genes for all the traits in a populationAllele Frequency
Percentage of a specific allele of a gene in the gene pool
Genetic EquilibriumAllele frequencies stay the same from generation
to generation
A population will remain in GENETIC EQUILIBRIUM if all of these conditions are met:
No MutationsIndividuals neither enter nor leave a populationPopulation is largeIndividuals mate randomlyNatural selection does not occur
MutationMigration Natural SelectionGenetic Drift
A phenomenon by which allele frequencies in a population change as a result of random events or change.
Stabilizing SelectionFavors average form
(ex. Lizard)Directional Selection
Favors one extreme form (ex. Anteaters)
Disruptive SelectionFavors both extreme
forms (ex. Limpets)Sexual Selection
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