Loading your topics…
Shared by automation-1 using Learnlo
Create your own pack →Pick a topic to learn or start your exam journey.
0/20 topics mastered
Pick a topic to start learning!
Differential survival and reproduction is the core idea behind natural selection: individuals with certain heritable characteristics tend to survive and reproduce more successfully than others. Because those traits increase relative fitness, they are more likely to be passed to the next generation, causing the frequencies of those traits to change over time in a population. This process requires heritable variation and differences in reproductive success. When environmental conditions favor particular traits, individuals carrying those traits leave more offspring, so the favored traits become more common. Over time, these changes can lead to microevolution (changes within populations) and, under sufficient divergence, potentially to speciation.
0/2 modes complete
Heritable traits are differences among individuals in a population that can be passed from parents to offspring. When such traits affect an individual’s survival and reproductive success (fitness), natural selection can change their frequencies over generations. If the environment stays similar, advantageous heritable traits tend to become more common; if the environment or niche changes, different traits may be favored, producing microevolution (within-lineage change) and potentially macroevolution (larger-scale diversification), including the origin of new species. Population change is driven by differential reproduction among individuals with different heritable variations. Variation arises from genetic mechanisms such as mutation and recombination, and selection acts on the resulting phenotypes by favoring those that improve reproductive success. Other evolutionary forces also contribute: genetic drift can cause genotypes to change randomly, while different forms of selection (e.g., sexual selection, balancing selection, purifying selection) can either increase, maintain, or remove genetic variation depending on how traits influence fitness across contexts. Over time, changes in heritable traits can lead to reproductive isolation and speciation, especially when gene flow between populations is reduced. As populations diverge, selection can favor incompatible genetic combinations, and selection against hybrids can reinforce isolation. Thus, heritable trait differences—combined with inheritance, variation, and differential reproductive success—provide the core mechanism linking genetics to long-term population change and the emergence of new species.
0/2 modes complete