BIOL 1001 Chapter : Chapter 15
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How are populations, genes, and evolution related: evolution is a property of populations, a population includes all of the members of a species in a given area. Evolution is the change of allele frequencies within a population. Allele frequency: allele frequency of b = 40, allele frequency of b = 60% The hardy-weinberg principle: hypothetical model under which a population does not evolve, equilibrium population a hypothetical nonevolving population, so why is a hypothetical model important, the hardy-weinberg conditions are useful starting points for studying. Five conditions of hardy-weinberg principle the mechanisms of evolution: no mutations, no gene flow into or out of the population, large population, all mating must be random, no natural selection. If all of these conditions hold true the population will not evolve. So, we can predict five major causes of evolutionary change: mutation, gene flow, small population size, nonrandom mating, natural selection. Gene flow between populations changes allele frequencies: gene flow can increase genetic similarity.
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Related Questions
These all relate to exceptions to the inheritance patterns encountered by Mendel.â
Why do multiple and lethal alleles often result in modifications of the classic Mendelian monohybrid and dihybrid ratios?
Select the four correct statements.
-When an essential gene is mutated, it can result in a lethal phenotype. There are no classic Mendelian monohybrid and dihybrid ratios. |
-In the case of codominance, heterozygotes produce gene products from both alleles of a gene. Classic Mendelian monohybrid and dihybrid ratios are modified by codominance. |
-In the case of incomplete dominance, the phenotype of the heterozygote is distinct from and often intermediate to the phenotypes of homozygous individuals. Classic Mendelian monohybrid and dihybrid ratios are modified by incomplete dominance. |
-Genes exist in a large number of allelic versions and a diploid organism has two homologous gene loci that may be occupied by different alleles of the same gene. This can result in many different phenotypes for traits, which may not follow typical Mendelian ratios. |
-When an essential gene is mutated, it can result in a lethal phenotype. This results in a modification of classic Mendelian ratios. |
-The phenotype of the heterozygous genotype is distinct from and often intermediate to the phenotypes of the homozygous genotypes. The joint expression of both alleles in a heterozygote is called codominance. There are no classic Mendelian monohybrid and dihybrid ratios. |
-Genes exist in a large number of allelic versions, but in a diploid organism, only one allele of the gene can occupy one homologous gene loci. Classic Mendelian inheritance cannot explain this phenomenon. |
-Each gene produces a unique gene product. The effect of one allele in a heterozygote completely masks the effect of the other. Classic Mendelian genetics cannot explain this phenomenon. |