EVOLUTION STUDY NOTES
Microevolution:
• changes in gene (allele) frequencies and phenotype traits within a population and species.
• Happens over a shorter period of time (years)
Macroevolution:
• large-scale evolutionary changes including the formation of new species & taxa.
• happens over a much longer period of –Time (centuries, millenia).
Natural Mechanisms:
• a slow & random process that results in subtle changes to traits
• e.g. errors during DNA replication, uptake of bacterial/viral DNA sequence
• generates variation within a species population
Artificial Mechanisms: domestication or artificial selection (creating desired combination of traits via selective and cross breeding)
• a faster & directive process, results in a wide range of phenotypic change
• generates variations within a species population and
• given enough time, it can lead to the creation of new species in less time (cannot reproduce)
Artificial selection: The intentional reproduction of individuals that have desirable traits. Best understood as a contrast to natural selection
Artificial selection: humans determine which traits are advantageous and passed on
Natural selection: environment determines which traits are advantageous and passed on
Reproduction Isolation: pre-zygotic mechanisms: prevents mating post-zygotic mechanisms: prevents reproduction of interspecies

Synapomorphy : a derived trait shared by two or more species or groups (ex. All birds have feathers & are more closely related to each other than reptiles, which do not have feathers).
Symplesiomorphy: is an ancestral trait shared by two or more taxa.
Modes of Speciation:
Allopatric Speciation: Evolution of population into two different species caused by geographic isolation
Sympatric Speciation: Evolution of populations into new species within the same geographical area
Darwin Observations
• Observation 1: Individuals within a population vary in their traits (Genetic variation). Some of these variable traits are heritable-passed on to offspring.
• Observation 2: More offspring are produced than can survive because of limited resources such as food and nesting sites. (struggle for existence and overproduction of offspring)
• Observation 3: Individuals with advantageous traits will survive and reproduce (differential survival and heredity)
• Result: The more advantageous trait, that allows for more offspring to survive will become more common EVOLUTION STUDY NOTES
Microevolution:
• changes in gene (allele) frequencies and phenotype traits within a population and species.
• Happens over a shorter period of time (years)
Macroevolution:
• large-scale evolutionary changes including the formation of new species & taxa.
• happens over a much longer period of –Time (centuries, millenia).
Natural Mechanisms:
• a slow & random process that results in subtle changes to traits
• e.g. errors during DNA replication, uptake of bacterial/viral DNA sequence
• generates variation within a species population
Artificial Mechanisms: domestication or artificial selection (creating desired combination of traits via selective and cross breeding)
• a faster & directive process, results in a wide range of phenotypic change
• generates variations within a species population and
• given enough time, it can lead to the creation of new species in less time (cannot reproduce)
Artificial selection: The intentional reproduction of individuals that have desirable traits. Best understood as a contrast to natural selection
Artificial selection: humans determine which traits are advantageous and passed on
Natural selection: environment determines which traits are advantageous and passed on
Reproduction Isolation: pre-zygotic mechanisms: prevents mating post-zygotic mechanisms: prevents reproduction of interspecies

Synapomorphy : a derived trait shared by two or more species or groups (ex. All birds have feathers & are more