Evolution Evidence and Mechanisms Flashcards
Grade 9 · Science · Flashcards
Master the key concepts, mechanisms, and evidence supporting evolutionary theory for Grade 9.
Flashcards
- Natural Selection
- The process where individuals with heritable advantageous traits reproduce more, increasing those traits' frequency over generations.
- Mutation
- A random change in the DNA sequence; the ultimate source of all new genetic variation in populations.
- Genetic Drift
- Random changes in allele frequencies due to chance; most pronounced in small populations; not driven by selection.
- Gene Flow
- Transfer of alleles between populations via migration; reduces genetic differences between populations.
- Homologous Structures
- Similar anatomical structures in different species inherited from a common ancestor, e.g., mammalian forelimbs.
- Analogous Structures
- Structures with similar functions but different evolutionary origins, reflecting convergent evolution (e.g., bird and insect wings).
- Vestigial Structures
- Reduced or non-functional remnant structures that were functional in ancestors, evidence of evolutionary change.
- Speciation
- The formation of new, distinct species; requires reproductive isolation so populations diverge genetically over time.
- Adaptive Radiation
- Rapid evolution of many diverse species from a single ancestor to fill different ecological niches.
- Founder Effect
- A type of genetic drift when a new population is established by a small group, leading to low genetic diversity.
- Biogeography
- The study of the geographic distribution of species; related species on neighboring landmasses support common descent.
- Fitness
- An organism's reproductive success relative to others in the population; organisms with higher fitness leave more offspring.
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