MACROEVOLUTION

Flashcards covering key concepts, definitions, and theories related to macroevolution, speciation, and evolutionary patterns.

Macroevolution

Large-scale evolutionary changes occurring over long periods, leading to the formation of new species and higher taxonomic groups.

Microevolution

Small-scale evolutionary changes within a species or population over shorter periods.

Species

A group of organisms, for which there is no single true definition, but various concepts attempt to define it.

Biological Species Concept

A concept defining a species based on the ability of individuals to interbreed and produce fertile offspring.

Phylogenetic Species Concept

A concept defining species by identifying patterns of ancestry or who is related to whom, often focusing on morphological similarities.

Ecological Species Concept

A concept defining a species as a group of organisms exploiting a single niche, focusing on natural selection and influences of varied habitats.

Reproductive Isolating Barrier (RIB)

Mechanisms or barriers that prevent two populations from interbreeding and producing fertile offspring, essential for speciation.

Prezygotic Barriers

Reproductive isolating barriers that prevent the formation of a zygote, occurring before fertilization.

Ecological / Habitat Isolation

A prezygotic barrier where species live in different habitats or locations, preventing them from meeting and mating.

Temporal Isolation

A prezygotic barrier where species breed during different times of day, seasons, or years, preventing interbreeding.

Ethological / Behavioral Isolation

A prezygotic barrier where species have different courtship rituals or mating behaviors, preventing successful mating.

Mechanical Isolation

A prezygotic barrier where physical differences in reproductive structures prevent successful mating.

Gametic Mortality or Incompatibility

A prezygotic barrier where the gametes (sperm and egg) of different species are incompatible or fail to survive.

Postzygotic Barriers

Reproductive isolating barriers that prevent successful reproduction after a zygote has formed, often leading to non-viable or sterile offspring.

F1 Inviability

A postzygotic barrier where hybrid offspring (F1 generation) do not survive to birth or maturity.

F1 Sterility

A postzygotic barrier where hybrid offspring (F1 generation) survive but are infertile and cannot reproduce.

Hybrid Breakdown

A postzygotic barrier where first-generation hybrids are viable and fertile, but subsequent generations (F2 or backcrosses) are inviable or sterile.

Genetic Differentiation

The process by which genetic differences accumulate between isolated populations due to mutation, genetic drift, and natural selection.

Anagenesis

A type of straight-line evolution where one species gradually changes over time into a new species, without branching.

Cladogenesis

A type of branching evolution where one species splits into two or more new species, increasing biodiversity.

Adaptive Radiation

The rapid diversification of a single ancestral species into multiple new species, each adapted to exploit different environmental niches.

Gradualism

A model of evolution proposing that evolutionary change occurs slowly and steadily over long periods through the accumulation of small variations.

Punctuated Equilibrium

A model of evolution proposing that species remain largely unchanged (stasis) for long periods, with short bursts of rapid evolutionary change.

Relative Dating

A method of determining the age of fossils or artifacts by comparing their position in geological strata or association with other dated materials.

Chronometric Dating

A method of determining the absolute age of fossils or artifacts using techniques that provide a numerical age, such as radiometric dating.

Homologous Traits

Traits in two or more species that have similar structures because they were derived from a common ancestor, regardless of current function.

Homoplasy / Analogous Traits

Physical traits in different species that have similar functions but different structures, having evolved independently rather than from a common ancestor.

Parallel Evolution

A type of homoplasy occurring in closely related species that have recently diverged, where similar adaptations evolve independently due to similar selective pressures.

Convergent Evolution

A type of homoplasy where independent evolution of similar adaptations occurs in rather distinct evolutionary lines or distantly related species.

Primitive Trait

A trait that has not changed from the ancestral state within a phylogenetic lineage.

Derived Trait

A trait that has changed or evolved from the ancestral state within a phylogenetic lineage.

Cladistics

An approach to biological classification that groups organisms based only on shared derived traits, ignoring shared primitive traits.

Phenetics

An approach to biological classification that groups organisms based on overall physical similarities, considering both primitive and derived shared traits.

Palmaris Longus Muscle

A muscle in the forearm that is vestigial in many humans (10-20% lack it) and serves as an example of a structure that once had function but no longer does, with no selective pressure acting against its presence.

Orthogenesis

A debunked misconception that evolution is directed towards a specific goal or predetermined path.