Evolution Test - Definitions

• Neutral mutation


  Provide no benefit or harm to the individual
• Harmful mutation


  Reduce the reproductive success of an organism
• Beneficial mutation


  Produce a change in an individual's phenotype that gives the individual an advantage
• Artificial selection


  Directed breeding in which individuals that exhibit a particular trait are chosen as parents of the next generation; artificial selection is used to produce new breeds or varieties of plants and animals
• Fossil


  Any ancient remains, impressions, or traces of an organism or traces of its activity that have been preserved in rocks or other mineral deposits in Earth's crust
• Immutable


  Unable to change
• Paleontology


  The scientific investigation of prehistoric life through the study of fossils
• Catastrophism


  The theory that the patterns of fossils could be accounted for by a series of global catastrophes that wiped out most species on Earth
• Uniformitarianism


  The theory that geological changes are slow and gradual and that natural laws and processes have not changed over time
• Biogeography


  The scientific study of the geographic distribution of organisms based on both living species and fossils
• Homologous features


  Structures with a common evolutionary origin that may serve different functions in modern species. Example: Bat wing and human arm
• Analogous feature


  A structure that performs the same function as another but is not similar in origin or anatomical structure. For example: Bird and insect wings
• Vestigial feature


  Structures that are not used in living organisms (digits in dogs and horses, human tail bones, wisdom teeth); could indicate change over time
• Survival of the fittest


  A phrase that has been used to describe the process of natural selection
• Adaptation


  A characteristic or feature of a species that makes it well suited for survival or reproductive success in its environment
• Natural selection


  The way in which nature favours the reproductive success of some individuals within a population over others
• Radioisotope


  An atom with an unstable nucleus that is capable of undergoing radioactive decay
• Half-life


  The time required for half the quantity of a radioactive substance to undergo decay; the half-life is a constant for any given isotope
• Gene pool


  The complete set of all alleles contained within a species or population
• Modern evolutionary synthesis


  The modern theory of evolution that takes into account all branches of biology
• Plate tectonics


  The scientific theory that describes the large-scale movements and features of Earth's crust
• Pseudogene


  A vestigial gene that no longer codes for a functioning protein/gene
• Directional selection


  Selection that favours an increase or decrease in the value of a trait from the current population average
• Stabilizing selection


  Selection against individuals exhibiting traits that deviate from the current population average
• Disruptive selection


  Selection that favours two or more variations of a trait that differ from the current population average
• Sexual selection


  Differential reproductive success caused by variation in the ability to obtain mates; results in sexual dimorphism, and mating and courtship behaviours
• Genetic drift


  Changes to allele frequency as a result of chance; such changes are much more pronounced in small populations
• Genetic bottleneck


  A dramatic, often temporary, reduction in population size, usually resulting in significant genetic drift
• Founder effect


  Genetic drift that results when number of individuals separate from their original population and establish a new population
• Hardy-Weinberg principle


  In large populations in which only random chance is at work, allele frequencies are expected to remain constant from generation to generation
• Microevolution


  Changes in gene (allele) frequencies and phenotypic traits within a population and species
• Speciation


  The formation of new species
• Reproductive isolating mechanism


  Any behavioural, structural, or biochemical trait that prevents individuals of different species from reproducing successfully together
• Prezygotic mechanism


  A reproductive isolating mechanism that prevents interspecies mating, and fertilization. For example, can occur due to physical barriers (ecological isolation, mechanical isolation, gametic isolation) or behavioural barriers (temporal isolation, behavioural isolation)
• Postzygotic mechanism

  A reproductive isolating mechanism that prevents maturation and reproduction in offspring from interspecies reproduction
• Allopatric speciation


  The formation of a new species as a result of evolutionary changes following a period of geographic isolation
• Sympatric speciation


  The evolution of of populations within the same geographic area into separate species
• Adaptive radiation


  The relatively rapid evolution of a single species into many new species, filling a variety of formerly empty ecological niches
• Divergent evolution


  The large-scale evolution of a group into many different forms
• Convergent evolution


  The evolution of similar traits in distantly related species