Chapter 5 Flashcards
(19 cards)
evolution
descent with modification
the central idea that all life on earth shares a common ancestor
charles darwin
theory of evolution via natural selection
evolution and ecology are fundamentally intertwined
genetic variation and trait variation (evolution)
ecological interactions and ecosystem functions (ecology)
natural selection
the differential success of of individuals within the population that results from their interaction with the environment
two conditions of natural selection
variation among individuals is heritable
variations results in differences among individuals in their survival and reproduction as a result of their interaction with the environment
variation
a trait under evolution must vary genetically within a population
inheritance
genetic traits are inherited from parents to offspring
selection
organisms with traits that increase survival and reproduction are more likely to pass on their genes to the next generation
time
evolutionary change happens only between generations
fitness
proportionate contribution of an individual to a future generation
adaptation
any heritable trait of an organism that’s evolved by natural selection to maintain or increase fitness under a given environmental condition
directional selection
when the mean value of a trait is shifted toward one extreme over another
stabilizing selection
favors individuals near the population mean at the expense of two extremes
disruptive selection
members of a population are subject to different selection pressures
mutation
heritable changes in a gene or chromosome
genetic drift
change in allele frequencies as a result of random chance
is stronger in smaller populations due to probability theory
migration
the movement of individuals between local populations
gene flow
the movement of genes between populations
hardy weinberg principle
states that no evolutionary change occurs through the process of sexual reproduction itself
