unit7 bio

natural selection

The process by which organisms with traits better suited to their environment survive and reproduce more successfully, passing those traits to future generations

adaptation

A heritable trait that improves an organism's ability to survive and reproduce in a specific environment.

Fitness

The ability of an organism to survive and reproduce in its environment, often measured by the number of offspring it contributes to the next generation

Variation

Differences in physical traits, behaviors, or genetic makeup among individuals in a population, which can arise from mutations, genetic recombination, and environmental influences

Inheritance

The passing of genetic traits from parents to offspring through DNA.

Differential Reproduction

The idea that organisms with advantageous traits reproduce more successfully than others, leading to changes in the population over time

Speciation

The formation of new and distinct species due to evolutionary processes like natural selection, genetic drift, or geographic isolation.

Population

A group of individuals of the same species living in a specific area that can interbreed and produce fertile offspring.

Phenotype

The observable traits or characteristics of an organism, resulting from the interaction of its genotype with the environment

Genotype

The genetic makeup of an organism, consisting of the specific alleles it inherits from its parents.

Allele Frequency

The proportion of a particular allele within a population's gene pool, which can change over time due to evolutionary forces.

Genetic Drift

A random change in allele frequencies within a population due to chance events, which can have a significant impact on small populations.

Gene Flow

The movement of alleles between populations due to migration, which can introduce new genetic variation.

Phylogenetic Tree

A diagram that represents the evolutionary relationships among species, showing common ancestors and divergence over time.

Clade

A group of organisms that includes a common ancestor and all of its descendants, representing a single branch on a phylogenetic tree

Convergent Evolution

The process by which unrelated species evolve similar traits due to similar environmental pressures or ecological roles.

Divergent Evolution

The process by which two or more related species evolve different traits and become increasingly distinct, often due to adaptation to different environments.

Extinction

The permanent loss of a species when its last individuals die out, often caused by environmental changes, competition, or human activities.

Mutation

A random change in DNA that can introduce new genetic variation.

Hardy-Weinberg Equilibrium

A principle stating that allele frequencies remain constant in a population unless evolutionary forces act upon them.

Bottleneck Effect

A type of genetic drift where a population's size is drastically reduced, leading to decreased genetic variation

Founder Effect

A type of genetic drift that occurs when a small group establishes a new population with a different allele frequency than the original.

Stabilizing Selection

Favors intermediate traits, reducing variation in a population.

Directional Selection

Favors one extreme trait, shifting the population's characteristics in that direction.

Disruptive Selection

Favors both extreme traits over the intermediate, leading to increased genetic diversity.

Sexual Selection

A form of natural selection where traits increase mating success rather than survival.

Fossil Record

Preserved remains or traces of ancient organisms that show changes over time.

Homologous Structures

Similar structures in different species that indicate common ancestry

Analogous Structures

Similar structures in different species that evolved independently due to similar environmental pressures (resulting from convergent evolution).

Vestigial Structures

Reduced or unused structures that were functional in an organism's ancestors.

Biogeography

The study of the geographic distribution of species, supporting evolution through patterns of migration and isolation.

Comparative Embryology

The study of embryos of different species to find similarities that suggest common ancestry.

Molecular Evidence

DNA and protein comparisons that show evolutionary relationships among species.

Allopatric Speciation

The formation of new species due to geographic isolation.

Sympatric Speciation

The formation of new species without physical separation, often due to behavioral or genetic changes.

Prezygotic Barriers

Factors that prevent mating or fertilization between species (e.g., behavioral, temporal, or mechanical isolation).

Postzygotic Barriers

Factors that prevent viable or fertile offspring from being produced (e.g., hybrid sterility or inviability).

Adaptive Radiation

The rapid evolution of multiple species from a common ancestor due to the exploitation of different ecological niches.

Punctuated Equilibrium

A theory that evolution occurs in rapid bursts of change followed by long periods of stability.

Gradualism

A theory that evolution occurs slowly and steadily over time

Taxonomy

The science of classifying organisms.

Binomial Nomenclature

The two-part scientific naming system for species (Genus species).

Monophyletic Group

A group that includes an ancestor and all its descendants (same as a clade).

Paraphyletic Group

A group that includes an ancestor but not all of its descendants.

Hominins

Early human ancestors and relatives that show bipedalism.

Bipedalism

Walking on two legs, a key trait in human evolution.

Cultural Evolution

The transmission of knowledge, behaviors, and technology through learning rather than genetic inheritance.