Darwin & His Influences
This scientist proposed that Earth's geological features change slowly over millions of years.
Who is Charles Lyell?
The term for a heritable trait that increases an organism's survival and reproductive success.
What is an adaptation?
The collection of all alleles found in a population.
What is a gene pool?
The Hardy-Weinberg principle says allele frequencies stay stable only when this is NOT happening.
What is evolution?
The type of speciation that occurs when two populations are separated by a physical geographic barrie
What is allopatric speciation?
This economist argued that human populations grow faster than food supplies, inspiring Darwin's idea of competition for survival.
Who is Thomas Malthus?
Structures like the human arm, whale flipper, and bat wing that share a common evolutionary origin are called this.
What are homologous structures?
A trait controlled by many genes, such as height or skin color, that produces a bell-curve distribution of phenotypes.
What is a polygenic trait?
In the equation p² + 2pq + q² = 1, this term represents the frequency of heterozygous individuals in the population.
What is 2pq?
Reproductive isolation where two populations breed at different times of year, preventing them from interbreeding.
What is temporal isolation?
Lamarck incorrectly proposed that traits gained during an organism's lifetime could be passed to offspring through this mechanism.
What is inheritance of acquired traits?
Type of selection where extreme phenotypes on BOTH ends of the bell curve are favored, eventually splitting the population into two groups.
What is disruptive selection?
These three processes are the main sources of genetic variation in a population.
What are mutations, gene shuffling, and lateral gene transfer?
Random changes in allele frequency that occur in small populations — not driven by natural selection.
What is genetic drift?
When unrelated species independently evolve similar traits due to similar environmental pressures — like dolphins and sharks both evolving streamlined bodies.
What is convergent evolution?
Darwin visited this specific island chain and observed finches with different beak shapes adapted to different food sources.
What are the Galapagos Islands?
These reduced, non-functional structures — like the human tailbone or whale leg bones — serve as evidence that species share common ancestors.
What are vestigial organs?
Type of natural selection that eliminates extreme phenotypes and keeps the population clustered around the average, like human birth weight.
What is stabilizing selection?
This effect occurs when a small group breaks away from a larger population and founds a new colony, leading to reduced genetic diversity.
What is the Founder Effect?
Darwin's concept that all species alive today have changed over time from ancestral species, forming a single tree of life.
What is descent with modification?
These FIVE conditions must ALL be met for a population to remain in Hardy-Weinberg equilibrium.
What are: large population, random mating, no mutations, no gene flow, and no natural selection?
These FOUR lines of evidence Darwin used to support his theory of evolution by natural selection.
What are the fossil record, geographic distribution of species, homologous structures, and similarities in early development?
This type of selection causes the bell curve to shift toward one extreme — for example, when food becomes scarce and only large-beaked birds survive.
What is directional selection?
This bottleneck effect example explains why cheetahs today have extremely low genetic diversity — nearly the entire population was wiped out by this type of event long ago.
What is a population bottleneck (mass die-off)?
This evolutionary model proposes that species remain largely unchanged for long periods, then undergo rapid bursts of change — the opposite of gradualism.
What is punctuated equilibrium?