Definition: Evolution shows a lag in following a shifting adaptive optimum—response to selection pressure is not instantaneous.

Definition: μ ≈ 10⁻⁸ per base per generation (~1 in 10⁸ bases).

Definition: The replacement of one nucleotide or amino acid by another in an entire population—i.e., fixation of a mutation.

Definition: A division of geological time that is smaller than an eon and is subdivided into periods.

Drift is strongest in small populations, where random fluctuations have a larger impact on allele frequencies.

Definition: The proportional change in fitness relative to a reference genotype; measures strength and direction of selection.

Cannot be ignored because species share traits due to common ancestry, violating independence assumptions in statistical comparisons.

Definition: All traits are built upon pre-existing traits; evolution depends on what was inherited rather than starting from scratch.

A statistical error that occurs when multiple measurements are treated as independent data points, even though they are not, leading to artificially low p-values and false conclusions.

A division of geological time that is smaller than an era and is subdivided into epochs.

Definition: The duplicate can be lost, retained with the same function, or diverge through neofunctionalization or subfunctionalization.

Definition: A non-functional DNA sequence resembling a gene; can arise from non-functional duplicates or formerly functional genes.

Approximate constancy of amino-acid substitution rates across species and lineages—forming the basis for the 'molecular clock.'

Definition: By counting new mutations in offspring or descendant lineages using DNA sequencing or mutation-accumulation experiments.

Definition: It can be advantageous, neutral, or lead to gene trafficking.

Definition: Paralogs.

Characterized by significant evolutionary developments in mammals and birds.

What does this equation represent?

Underestimates of true substitution rates because multiple substitutions can occur at the same site, masking earlier changes.

What is gene duplication?

Definition: Under selection, k = 4Ne ua s, which should vary widely because Ne, ua, and s differ among species.

Cooling crust, continent formation, start of life; biogenic graphite ≈ 3.7 bya; low oxygen reducing atmosphere.

Definition: Typically synonymous and neutral; evolve mainly by genetic drift.

An experiment that demonstrated that simple organic molecules form spontaneously in a simulated reducing atmosphere with electrical energy.

Common ways protein coding genes evolve in the human genome

Can occur by either natural selection (advantageous mutations) or genetic drift (neutral ones).

Definition: The integration of Mendelian genetics with Darwinian natural selection—explaining evolution as changes in allele frequencies due to selection, mutation, drift, and migration.

Definition: They can be lost, retain their function, diverge biochemically, or evolve new or subdivided functions.

Genetic mutation that involves the loss of a segment of DNA, which can range from a single nucleotide to an entire gene or even multiple genes.

Process in which a single gene with multiple functions undergoes duplication, resulting in copies that specialize by taking on different parts of the original functions.

There is no relationship.

Earliest Earth formation before known rocks; Zircon crystals ≈ 4.3 bya; possible biotic life ≈ 4.1 bya.

The natural process by which life arises from non-living matter through chemical evolution.

A method of determining the exact age of fossils and rocks, often using techniques like radiometric decay.

Definition: Small population size, founder effects, bottlenecks, unequal sex ratios, fluctuating population size.

Definition: The expected number of generations to the most recent common ancestor for two alleles; θ = 4Neμ, a measure of neutral genetic diversity (also estimated by π).

A host shift from hawthorn to apples created reproductive isolation between populations, marking the early stages of sympatric speciation.

Definition: 107 populations, each with 16 flies (8 males, 8 females), all initially heterozygous; each generation was formed by random sampling of 16 individuals.

The geological period in which the ancestral eye-development network likely originated.

Characterized by the formation and diversification of vascular plants.

Definition: The Primordial Soup or Heterotrophic theory.

Definition: A conceptual surface describing how fitness varies with phenotype; peaks represent trait combinations with highest fitness.

Caused by rapid growth and diversification of land plants generating severe global cooling.

The approach integrates evolutionary history and statistical analysis to infer whether specific traits evolved as adaptations to ecological pressures rather than as byproducts of shared descent.

Definition: Proposed by Alexander Oparin (1924) and J. B. S. Haldane (1929).

Definition: μ = probability that an offspring carries a new mutation.

Term: Probability that a new neutral mutation fixes in a population

Results from a single base substitution in the β-globin gene.

Within populations, short-term genetic change.

Typically result in synonymous mutations; Most are neutral or nearly neutral.

Definition: Homology is supported by shared developmental pathways or gene networks; homoplasy arises through analogous adaptations with different underlying mechanisms.

Definition: Occurring or existing only if (certain circumstances) are the case; dependent on.

Definition: DNA sequence that resembles a functional gene but is inactive or non-functional due to mutations over the course of evolution.

Typically change the AA (non-synonymous mutations); 70-97% are deleterious (decrease fitness); Removed by purifying selection.

Definition: W11 = 1, W12 = 1 + s, W22 = 1 + 2s.

Genetic change that alters the sequence of amino acids in a protein.

There are no elephants in Hawaii because they could not disperse there—historical isolation explains their absence.

Characterized by the emergence of the first primates and the return of whales and dolphins to the sea.

No – drift is random, but its magnitude can be statistically estimated based on population size.

Definition: Change codon without altering amino acid (neutral).

Describes the expected genetic structure of a population when evolution is not occurring.

Definition: Only when allele frequencies (p and q) change over time.

There is no correlation between genome size and number of coding genes.

Random sampling of alleles during reproduction—some alleles are lost or fixed by chance rather than selection.

Change the encoded amino acid.

Definition: Insecticide-resistance genes under selection pressure.

RNA molecules capable of catalyzing chemical reactions, supporting the RNA world theory.

Characterized by the diversification of animals, some developing shells, external skeletons or notochords.

Characterized by the diversification of dinosaurs and gymnosperm plants, and the emergence of the first birds and mammals.

A change in a single nucleotide base pair; transitions are more common than transversions due to DNA-strand stability.

By altering DNA sequences that affect RNA transcription or protein structure/function, leading to changes in observable traits.

Amino-acid and nucleotide substitution rates remain approximately constant over time as long as the neutral mutation rate stays constant.

A group of individuals of the same species living in a specific area.

p(fixation) = initial allele frequency.

The process where new protein coding genes emerge from non coding DNA sequences.

Definition: A hypothetical mixture where organic molecules accumulated near shorelines or hydrothermal vents.

Definition: The neutral mutation rate (probability of a neutral mutation appearing per generation).

Definition: All organisms share the same genetic code, supporting descent from a single common ancestor.

The largest division of geological time, which is subdivided into eras.

An evolutionary change of large magnitude that produces new levels of biological organization (e.g., genes → genomes → cells → multicellular life).

Definition: Hemoglobin gene family.

Term: Whole genome duplication

Definition: End Ordovician, Late Devonian, End Permian, End Triassic, End Cretaceous.