Evolution refers to the genetic change in populations over successive generations. This process is driven by factors such as genetic variation, natural selection, and genetic drift.

Natural selection is a process where individuals with advantageous traits are more likely to survive and reproduce. This leads to the prevalence of those traits in subsequent generations.

An adaptation is a heritable trait that enhances an organism's survival and reproductive success. These traits are shaped and maintained by the process of natural selection.

A mutation is any change in the DNA sequence of an organism's genome. These changes create genetic variation, which can be acted upon by natural selection and other evolutionary mechanisms.

Fitness in evolutionary biology refers to the reproductive success of an organism. It is measured by the ability to survive, reproduce, and pass on genes to subsequent generations.

Genetic drift is a mechanism of evolution that causes random fluctuations in allele frequencies. Its effects are most pronounced in small populations, where chance events can significantly alter genetic makeup.

Gene flow refers to the movement of genes or alleles between interbreeding populations. This process can increase genetic diversity within a population by introducing new genetic material.

Speciation is the evolutionary process by which new species arise from existing ones. This often involves the development of reproductive barriers that isolate populations, leading to genetic divergence.

Convergent evolution occurs when unrelated species independently evolve similar traits as a result of having to adapt to similar environments or ecological niches. The similar streamlined shapes of sharks and dolphins are a classic example even though they do not share a recent common ancestor.

A phylogenetic tree is a diagram that depicts the evolutionary relationships among different species or groups based on similarities and differences in their physical or genetic characteristics. It helps illustrate how organisms have diverged from common ancestors over time.

The Hardy-Weinberg Principle provides a model where allele and genotype frequencies remain unchanged in an ideal population that is not subject to evolutionary forces. It sets the baseline conditions for understanding how populations evolve when those conditions are not met.

Mutations are changes in the genetic code that create new alleles and contribute to genetic diversity. This variation is the raw material upon which natural selection and other evolutionary forces act, driving evolutionary change.

Stabilizing selection favors individuals with average traits and reduces the frequency of extreme phenotypes. This process leads to a reduction in genetic variation within the population over time.

An adaptive trait is one that has evolved through natural selection because it increases an organism's fitness. These traits enable organisms to better survive and reproduce in their specific environments.

The concept of common ancestry holds that all life on Earth shares a common origin. It is a fundamental principle of evolutionary biology, highlighting the interconnectedness of all living organisms through evolutionary history.

Punctuated equilibrium proposes that evolution is characterized by long periods with little change, punctuated by short, rapid bursts of significant change. This contrasts with the gradualism model, which suggests that evolutionary change occurs steadily over time.

Allopatric speciation occurs when populations become geographically isolated and diverge into separate species. This process is driven by the lack of gene flow and differing selective pressures in distinct environments.

Sexual selection is a form of natural selection where traits that enhance an animal's ability to obtain mates become more common. Although some traits favored by sexual selection may be costly in terms of survival, they increase reproductive success.

A maladaptive trait can persist if it is closely linked to another trait that provides a selective advantage. Genetic linkage can allow a disadvantageous trait to be inherited along with a beneficial one, making complete elimination less likely.

Epigenetic modifications change how genes are expressed without altering the underlying DNA sequence. These modifications can sometimes be passed on to subsequent generations, thereby playing a role in evolutionary processes.