Measuring Diversity
Measuring the rate of species turnover or change in species composition when moving between two distinct local sites represents this specific scale of diversity.
Beta (β) diversity
When a severe natural disaster randomly eliminates a large portion of a population, the resulting chance change in allele frequencies is known as this specific form of genetic drift.
Bottleneck effect
A male donkey and a female horse mate to produce a healthy but completely sterile mule, illustrating this specific postzygotic barrier.
reduced hybrid fertility
Characterized by a subsoil layer of permafrost, this treeless biome is located between 60 and 75 degrees North latitude.
tundra
Natural selection acts directly on an organism's observable physical traits, known by what term
Phenotype
Measuring the species diversity contained within a single local, uniform site or habitat represents this scale of diversity, denoted by the first letter of the Greek alphabet
Alpha (α) diversity
This mode of natural selection favors phenotypes at both extreme tails of a trait spectrum while selecting against intermediate forms
disruptive selection
This type of speciation occurs in the exact same geographic area without physical separation, often driven by chromosomal errors like polyploidy in plants.
sympatric speciation
Chemical insecticides like DDT, widely sprayed in the 1950s, accumulate in high doses in top predators through this process.
biomagnification
What term describes changes in a population's allele frequencies caused specifically by random chance events
Genetic Drift
This baseline component of species diversity is measured simply by counting the total number of different unique species present within a given ecological community
species richness
When allele and genotype frequencies remain constant across generations because microevolution is not occurring, the population has reached this state.
Hardy-Weinberg equilibrium
When two previously isolated species produce unfit hybrids in a hybrid zone, natural selection actively strengthens prezygotic barriers through this process.
reinforcement
Located along maritime coasts between 30 and 50 degrees from the Equator, this biome features mild wet winters, dry summers, and fire-adapted evergreen shrubs.
Chaparral
What type of speciation is initiated when a physical geographic barrier divides a population and interrupts gene flow
Allopatric Speciation
Organisms that play a critical role in maintaining overall ecosystem health and structural stability relative to their presence are called this.
Keystone Species
What is the ultimate source of all brand-new heritable variation in a population, and what specific type of DNA alteration involves changing a single base pair?
DNA mutation
Reproductive isolation caused by unique courtship displays or species-specific signals—such as light flashing patterns in fireflies—represents this prezygotic barrier
behavioral isolation
Global climate patterns across Earth are primarily impacted by these three physical drivers.
What are latitude, wind/ocean currents, and topography
An agricultural region sprays the persistent pesticide DDT to control crop pests. Rain washes trace amounts of the chemical into a nearby lake, where it is absorbed by microscopic zooplankton. Small fish consume vast quantities of zooplankton, larger fish eat the small fish, and fish-eating birds of prey consume the larger fish. Testing reveals that the top-level birds of prey have accumulated extraordinarily high, toxic concentrations of DDT in their body tissues.
Question: What ecological term describes this process where a persistent toxin becomes increasingly concentrated at higher trophic levels of a food web?
Biomagnification
n variable environments, this reproductive strategy provides a major evolutionary benefit by shuffling alleles to create novel genotypes and repair genetic damage
Sexual Reproduction
What term describes evolutionary "leftovers"—anatomical structures that served a functional purpose in an ancestor but no longer serve a purpose in the modern species?
Vestigial Structures
Reduced hybrid viability, reduced hybrid fertility, and hybrid breakdown represent this main group of isolation mechanisms
postzygotic barriers
The Northern Hemisphere coniferous forest located between 50 and 70 degrees North latitude is dominated by needle-leaf evergreens and is also known by this name.
Taiga
What mode of natural selection shifts a population's overall phenotypic distribution toward one extreme tail over time?
Directional selection