Mechs. of Select
Lamarck mistakenly believed evolution was driven by these behaviors of organisms.
What is use and disuse of organs?
This geological principle states that older, undisturbed volcanic or sedimentary rock layers lie beneath younger layers.
What is the principle of superposition?
These anatomical structures share a common origin and skeletal blueprint but can serve entirely different functions in modern species.
What are homologous structures?
This term describes the total collection of all alleles present within a specific, interbreeding population.
What is a gene pool?
This type of selection on polygenic traits favors both extreme phenotypes.
What is disruptive selection?
While natural selection acts directly on an organism's observable phenotype, evolution is defined as a change in these frequencies over time.
What are allele frequencies?
This method estimates a fossil's age by comparing its placement in rock strata (layers).
What is relative dating?
The wings of a dragonfly and the wings of a hawk serve the same function but evolved independently, making them this type of structure.
What are analogous structures?
This mechanism of evolution alters allele frequencies purely through random chance events, rather than environmental fitness.
What is genetic drift?
This specific mode of speciation occurs when a physical geographic barrier completely cuts off gene flow between populations.
What is allopatric speciation?
This specific type of selection explains why male peacocks maintain flashy, survival-hindering feathers to attract mates.
What is sexual selection?
This term defines the fixed amount of time required for a set amount of a radioactive isotope's atoms to decay.
What is a half-life?
Non-functional evolutionary remnants, like the human appendix or a whale's pelvic bones, are known as these types of structures.
What are vestigial structures?
This specific type of genetic drift occurs when a catastrophic event randomly and drastically reduces a population's size.
What is the bottleneck effect?
This macroevolutionary pattern is shown by a single species rapidly diversifying into many distinct species.
What is adaptive radiation?
This human-driven process reduces genetic diversity by breeding organisms for specific desired traits.
What is artificial selection?
If a radioactive isotope has a half-life of 5,000 years, this is the absolute age of a fossil with only 25% of the parent isotope remaining.
What is 10,000 years?
The fused elytra of a ground-dwelling beetle are an example of this type of structure.
What are vestigial structures?
To maintain a non-evolving Hardy-Weinberg equilibrium, the population must experience this type of mating.
What is non-random mating?
This evolutionary model describes long periods of stability interrupted by brief, rapid bursts of change.
What is punctuated equilibrium?
Environmental factors like antibiotics or pesticides do not cause mutations; instead, they act as this type of evolutionary force.
What is a selective pressure?
The ancient, photosynthetic cyanobacteria caused this to happen 2.4 billion years ago.
What are rising oxygen levels?
Between DNA sequences, homologous structures, or analogous structures, this one provides the least reliable evidence for common ancestry.
What are analogous structures?
This notation, used in calculating Hardy-Weinburg equilibrium, represents the proportion of heterozygous individuals.
What is 2pq?
This reciprocal evolutionary pattern occurs when two closely interacting species exert selective pressures on each other's survival over time.
What is coevolution?