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Instructional design theories created by Reigeluth include Elaboration Theory and Simulation theory. In Elaboration Theory, [2] [3] [4] content to be learned is arranged so that concepts that are more simple and general build up to progressively narrower and more detailed concepts, thereby placing new content in a meaningful context, [5] consistent with schema theory.
The hypothesis was intended to explain the constant (age-independent) extinction probability as observed in the paleontological record caused by co-evolution between competing species; [1] however, it has also been suggested that the Red Queen hypothesis explains the advantage of sexual reproduction (as opposed to asexual reproduction) at the ...
A number of different Markov models of DNA sequence evolution have been proposed. [1] These substitution models differ in terms of the parameters used to describe the rates at which one nucleotide replaces another during evolution. These models are frequently used in molecular phylogenetic analyses.
Finally, integrative models—mixing sequence evolution and reconciliation—can compute a joint likelihood via dynamic programming (for both reconciliation and gene sequences evolution), [40] use Markov chain Monte Carlo to include molecular clock to estimate branch lengths, in a DL model [34] or with a relaxed molecular clock, [99] and in a ...
In biology, a substitution model, also called models of sequence evolution, are Markov models that describe changes over evolutionary time. These models describe evolutionary changes in macromolecules, such as DNA sequences or protein sequences, that can be represented as sequence of symbols (e.g., A, C, G, and T in the case of DNA or the 20 "standard" proteinogenic amino acids in the case of ...
Professor of biology Jerry Coyne sums up biological evolution succinctly: [3]. Life on Earth evolved gradually beginning with one primitive species – perhaps a self-replicating molecule – that lived more than 3.5 billion years ago; it then branched out over time, throwing off many new and diverse species; and the mechanism for most (but not all) of evolutionary change is natural selection.
Phylogenetics compares and analyzes the sequences of single genes, or a small number of genes, as well as many other types of data. Four major areas fall under phylogenomics: Prediction of gene function; Establishment and clarification of evolutionary relationships; Gene family evolution; Prediction and retracing lateral gene transfer.
The finding that "Mitochondrial Eve" was relatively recent and African seemed to give the upper hand to the proponents of the Out of Africa hypothesis.But in 2002, Alan Templeton published a genetic analysis involving other loci in the genome as well, and this showed that some variants that are present in modern populations existed already in Asia hundreds of thousands of years ago. [31]