Final answer:
The Modern Evolutionary Synthesis is a foundational theory of biology that melds Darwin's natural selection with Mendelian genetics. It explains how evolutionary processes influence a population's genetics, leading to both microevolution and macroevolution.
Step-by-step explanation:
The Modern Evolutionary Synthesis is a unifying theory that describes the integration of Charles Darwin's theory of evolution through natural selection with Gregor Mendel's theories on genetics. This synthesis occured during the early 20th century and reconciled how evolutionary processes, like natural selection, could work with a population's genetic composition. Essential to this concept is the understanding of alleles, which are different forms of a gene, and their frequencies in a population. When the allele frequencies within a population change over time, this indicates that the population is evolving.
At the heart of the Modern Evolutionary Synthesis is the idea that microevolution, or small-scale changes within a species, over time can lead to macroevolution, which refers to the bigger picture of evolution, such as the emergence of different species or new taxonomic groups. It brings together observations from various biological disciplines including paleontology, systematics, and especially genetics within the context of population biology.
One critical aspect of this synthesis is the concept of populations being in Hardy-Weinberg equilibrium, a condition wherein the genetic variation in a population remains constant from one generation to the next in the absence of disturbing factors. If a population does not meet the criteria for Hardy-Weinberg equilibrium, it means that some form of evolutionary force is at play, leading to changes in allele frequencies over generations — signaling the process of evolution.