Evolution and Natural Selection Flashcards

Grade 12 · Science · Flashcards

Key evolution vocabulary and concepts for Grade 12 Science.

Flashcards

Evolution: Change in heritable characteristics of populations over successive generations.
Natural selection: Differential survival and reproduction based on heritable traits that affect fitness in a given environment.
Fitness: Relative reproductive success; how many viable offspring an organism leaves compared to others.
Adaptation: A heritable trait that increases an organism's fitness in its environment.
Genetic drift: Random changes in allele frequencies; strongest in small populations; can cause allele fixation or loss.
Founder effect: Genetic drift when a small group founds a new population, carrying limited genetic diversity.
Bottleneck effect: Drastic population reduction causes loss of genetic variation; surviving alleles may not represent original population.
Gene flow: Transfer of alleles between populations via migration; reduces genetic divergence between populations.
Allopatric speciation: Speciation by geographic isolation; separated populations diverge until reproductively incompatible.
Homologous structures: Anatomical features with same evolutionary origin but different functions; evidence of common descent.
Analogous structures: Similar function, different evolutionary origin; result of convergent evolution in unrelated lineages.
Hardy-Weinberg equilibrium: p² + 2pq + q² = 1; allele/genotype frequencies in a non-evolving population; baseline for detecting evolution.