Darwinian Evolutionary Theory: The Evidence
p. 106-112
Perpetual Change
? Perpetual change can be seen in the ______________________________________________.
? Fossil – _________________________________________________________________
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? Complete remains, petrified skeletal parts, molds, casts, impressions, or fossil excrement
? Exhibits organismal _______________________________ as well as changes in Earth’s environment
? Interpreting the Fossil Record
? Preservation is _____________________________
? Some materials are more likely to be fossilized than others
? Fossils are deposited in ____________________________________ layers
? New deposits form ____________________________________ old deposits
? Relative dating – ___________________________________________________
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? Index fossil – ________________________________________________
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? Geologic Time
? Earth’s history is divided into ________________________________________________
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? Radiometric dating
? Uses radioactive decay rates to determine the ___________________________ of rock formations
? Rocks over 2 billion years old can be dated with a probable error of __________
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? Fossil record of macroscopic organisms begins near the start of the Cambrian period
? _____________________________________________
Evolutionary Trends
? Evolutionary trends are directional changes in the ____________________________________ or ________________________________________________________ in a group of organisms.
? Clearly support Darwin’s principle of _________________________________________.
? Ex: evolution of horses
Common Descent
? Darwin proposed that all plants and animals have descended from an ancestral form into which life was first breathed.
? Phylogeny – _____________________________________________________________
? According to this theory, we should be able to trace the genealogies of all modern species backwards until they converge on ancestral lineages shared with other species, both living and extinct.
? Homology and Phylogenetic Reconstruction
? Homology – _____________________________________________________
? Ex: ______________________________________________________
? Bones of vertebrate limbs maintain characteristic structures and patterns of connection despite diverse modifications for different functions
? According to Darwin’s theory of common descent, the structures that we call homologies represent _____________________________________________________
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? The Descent of Man and Selection in Relation to Sex by Charles Darwin
? Devoted largely to the idea that humans share ___________________________ with apes and other animals.
? Based on ___________________________________________________
? Evolutionary processes generate ______________characteristics that are then inherited by subsequent generations.
? Origins of new homologies.
? The pattern formed by the sharing of new homologies among species provides evidence for common descent and allows us to _________________________________________
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? Phylogenetic trees – _______________________________________________________
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? Homologies form the basis for our systemic classification of all forms of life
? __________________________________________
? Groups fit within other groups
? ___________________________
? __________________________
? __________________________
? _________________________
? _________________________
? ___________________________
? _____________________________
? ______________________________
Phylogenetic tree
Once a derived trait is fixed in a lineage, all descendants of that lineage can be expected to _____________________________ the derived trait (or some modification thereof).
This diagram illustrates the idea that the traits of living species represent a summation of their evolutionary histories.
? Ontogeny, Phylogeny, and Recapitulation
? Ontogeny – ______________________________________________________________
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? Early _______________________________ and _________________________ evidence supports common descent
? Biogenetic law (_________________________________________________) – ontogeny (_______________________________________________________) repeats phylogeny (_______________________________________________________)
? Paedomorphosis
? __________________________________________________________________
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? Reverse recapitulation