Evolution Test Notes

Evolutionary Theory

Developed through fossil evidence, comparative anatomy, and genetics.

Natural Selection

Mechanism proposed by Darwin and Wallace, stating that organisms best adapted to an environment reproduce more.

Homologous Structures

Same structure, different function, indicating common ancestry.

Analogous Structures

Same function, different structure, indicating convergent evolution.

Vestigial Structures

Remnants of ancestral features that no longer serve a purpose.

Fitness

The ability of an organism to survive and reproduce.

Allopatric Speciation

A form of speciation that occurs when physical barriers separate populations.

Sympatric Speciation

A form of speciation that occurs without physical separation of populations.

Natural Selection Types

Includes Directional, Stabilizing, and Disruptive selection.

Genotype vs. Phenotype

Genotype refers to genetic makeup, Phenotype refers to observable traits.

Bottleneck Effect

A drastic reduction in population size that reduces genetic diversity.

Founder Effect

New population established from a small group of individuals.

Gradualism

Model of evolution where changes occur slowly and steadily.

Punctuated Equilibrium

Model of evolution characterized by long periods of stability interrupted by sudden changes.

Divergent Evolution

Evolution from a common ancestor resulting in different species.

Convergent Evolution

Different ancestors evolve similar traits due to similar environmental pressures.

Co-evolution

The process where two species evolve in response to each other.

Industrial Melanism

A phenomenon where dark-colored organisms become more common due to pollution.

Mutations

Changes in DNA that can be beneficial, neutral, or harmful.

Artificial Selection

Humans selectively breed traits in organisms, often seen in domestication.

Charles Darwin's Observations

During his visit to the Galapagos Islands, Darwin noted diverse species, particularly finches, which varied based on the different environments of each island.

Galapagos Finches

Darwin observed that finches had differently shaped beaks, adapted for the specific types of food available on their respective islands.

Theory of Evolution

Darwin's observations of species on the Galapagos inspired his ideas on natural selection and the evolution of species over time.

Island Biogeography

Darwin's work on the Galapagos highlighted how geographical isolation can lead to speciation.

Adaptive Radiation

Darwin noted that species on the Galapagos evolved into a variety of forms to adapt to different ecological niches.

Lamarck's Theory of Acquired Characteristics

Proposed that organisms can pass on traits acquired during their lifetime to their offspring.

Use and Disuse

Lamarck believed that body parts used extensively become larger and stronger, while those that are not used deteriorate.

Inheritance of Acquired Traits

Lamarck's idea that characteristics developed during an organism's life can be inherited by their offspring.

Example of Giraffes

Lamarck suggested that giraffes developed long necks because ancestors stretched their necks to reach leaves, passing this trait to future generations.

Contrast with Darwin's Theory

Unlike Lamarck's theory, Darwin's theory emphasizes natural selection and genetic inheritance rather than acquired characteristics.

Fitness

The ability of an organism to survive and reproduce in its environment.

Survival of the Fittest

The concept that individuals best adapted to their environment are more likely to reproduce.

Niche & Competition

Organisms compete for limited resources in their environment, such as food and habitat.

Transitional Forms

Fossils that exhibit traits of different groups, illustrating evolutionary changes over time.

Extinction Events

Periods when a large number of species become extinct, reshaping ecosystems and biodiversity.

Significance of Fossil Record

The fossil record is crucial for understanding the history of life, evolution, and past environments.

Five Mass Extinctions

Recognized periods of mass extinction include the Ordovician, Late Devonian, Permian, Triassic, and Cretaceous.

Fossils and Biodiversity

Fossils provide evidence of past organisms and help track changes in biodiversity over millions of years.

Embryological Evidence

Similarities in embryonic development across species indicate common ancestry and evolutionary relationships.

Biochemical Evidence

DNA similarities across different species suggest shared genetic heritage, supporting evolutionary theory.

Genetic Evidence

Shared proteins and genes among species reflect evolutionary connections and common descent.

Directional Selection

Favors one extreme phenotype over the other phenotypes in a population.

Stabilizing Selection

Favors the average phenotype and reduces variation in a population.

Disruptive Selection

Favors extreme traits and selects against average traits, leading to two or more contrasting phenotypes.

Gene Flow

The transfer of genetic material between populations through migration.

Effects of Gene Flow

Gene flow can introduce new alleles into a population, increasing genetic diversity and potentially enhancing adaptability.