Chapter 8 - Vocabulary Flashcards
Abiogenesis
the origin of life from non-living matter.
Adaptive Radiation
the relatively rapid evolution of a single species into many new species, filling a variety of formerly empty ecological niches.
Allopatric Speciation
the formation of a new species as a result of evolutionary changes following a period of geographic isolation.
Anthropoid
the group of primates that includes monkeys, apes, and humans.
Cambrian Explosion
the rapid evolution of most major animal phyla that took place over approximately 40 million years during the Cambrian period.
Cladistics
a method of determining evolutionary relationships based on the presence or absence of recently evolved traits.
Coevolution
a process in which one species evolves in response to the evolution of another species.
Convergent Evolution
the evolution of similar traits in distantly related species.
Derived Trait
a trait that has evolved relatively recently with respect to the species or groups being discussed.
Disruptive Selection
selection that favours two or more variations of a trait that differ from the current population average.
Directional Selection
selection that favours an increase or decrease in the value of a trait from the current population average.
Divergent Evolution
the large-scale evolution of a group into many different forms.
Founder Effect
genetic drift that results when a small number of individuals separate from their original population and establish a new population.
Genetic Bottleneck
a dramatic, often temporary, reduction in population size, usually resulting in significant genetic drift.
Genetic Drift
changes to allele frequency as a result of chance; such changes are much more pronounced in small populations.
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.
Hominid
all species descended from the most recent ancestor of chimpanzees and humans that are on the human side of the lineage.
Macroevolution
large-scale evolutionary changes including the formation of new species and taxa.
Microevolution
changes in gene (allele) frequencies and phenotypic traits within a population and species.
Post-zygotic Mechanism
a reproductive isolating mechanism that prevents maturation and reproduction in offspring from interspecies reproduction.
Pre-zygotic Mechanism
a reproductive isolating mechanism that prevents interspecies mating and fertilization (for example, ecological isolation, temporal isolation, and behavioural isolation).
Primate
a group of relatively large-brained, mostly arboreal mammals that includes prosimians, monkeys, apes, and humans.
Prosimian
the group of primates that includes lemurs, lorises, and tarsiers.
Reproductive Isolation Mechanism
any behavioural, structural, or biochemical trait that prevents individuals from different species from reproducing successfully together.
Sexual Selection
differential reproductive success caused by variation in the ability to obtain mates; results in sexual dimorphism, and mating and courtship behaviours.
Speciation
the formation of new species.
Stabilizing Selection
selection against individuals exhibiting traits that deviate from the current population average.
Sympatric Speciation
the evolution of populations within the same geographic area into separate species.
Synapomorphy
a derived trait shared by two or more species or groups.
Theory of Gradualism
a theory that attributes large evolutionary changes in species to the accumulation of small and ongoing changes and processes.
Theory of Punctuated Equilibrium
a theory that attributes most evolutionary changes to be relatively rapid spurts of change followed by long periods of little or no change.
Transitional Form
a fossil or species intermediate in form between two other species in a direct line of descent.
