Genetic drift
This occurs when a sudden, random environmental catastrophe drastically reduces a population's size, leaving a non-representative group of survivors.
What is a population bottleneck?
The movement of individuals that drives gene flow.
What is migration?
This type of point substitution changes a codon but encodes the exact same amino acid, largely due to the redundancy of the genetic code
What is a synonymous (or silent) mutation?
This is what natural selection acts like when it removes poorly performing traits from populations.
What is a filter?
In this specific form of non-random mating, individuals preferentially choose mates that are genetically dissimilar to themselves, which helps maintain high levels of heterozygosity.
What is negative assortative mating?
This happens when a small, isolated group of individuals migrates to establish a new population, carrying only a fraction of the original gene pool's diversity
What is the founder effect?
While genetic drift tends to cause isolated populations to diverge genetically, gene flow acts to do this to their allele frequencies.
What is homogenize them?
These mutations alter the amino acid sequence of a protein product and are frequently subject to negative or purifying selection.
What is a nonsynonymous mutation?
Unlike genetic drift, natural selection changes allele frequencies based on this measure of an organism's survival and reproductive success.
What is fitness?
This evolutionary outcome of gene duplication occurs when a duplicated gene pair divides the original ancestral workloads or tasks between them.
What is subfunctionalization?
Because of random sampling error, genetic drift has a much larger, faster impact on allele frequencies in this type of population compared to a massive one.
What is a small population?
This specific type of evolutionary fitness measures not just an organism's own reproductive success, but also how it's fitness compares to others in the same population.
What is relative fitness?
Caused by the insertion or deletion of a single nucleotide, this type of mutation shifts the downstream reading frame and typically creates a nonfunctional protein.
What is a frameshift mutation?
This form of selection favors phenotypes at one extreme of a trait distribution, shifting the population's mean trait value in a single direction over generations.
What is directional selection?
This is an evolutionary theory proposing that species must constantly adapt, evolve, and reproduce just to survive while competing against ever-evolving opposing organisms
What is the Red Queen Hypothesis?
Unlike natural selection, genetic drift changes allele frequencies purely as a result of this property
What is random sampling error?
When individuals migrate and successfully breed between two separate groups, gene flow acts to reduce this statistical measure of genetic difference between them.
What is genetic divergence (or differentiation)?
This chromosome-flipping mutation occurs when a chromosome segment breaks off, rotates 180 degrees, and reattaches.
What is an inversion?
This specific mode of selection favors intermediate phenotypes while acting against both phenotypic extremes, thereby reducing overall population variance.
What is stabilizing selection?
Often resulting from errors during meiosis or mitosis where an organism gains extra complete sets of chromosomes.
What is polyploidy?
The effect genetic drift has on the genotype frequencies of populations.
What is loss of genetic variation?
If gene flow between two isolated populations is completely cut off, it removes the homogenizing effect and allows this ultimate evolutionary splitting process to proceed.
What is speciation?
This is a nonfunctional segment of DNA that structurally resembles a functional gene but has lost the ability to encode a standard protein
What is a pseudogene?
This term describes a genetic phenomenon where a single gene influences multiple distinct phenotypic traits, sometimes leading to trade-offs.
What is pleiotropy?
a sexual selection mechanism where persistent female choice drives the rapid evolution of exaggerated, seemingly maladaptive male physical traits (think peacock tails...)