Evolution and Genetics Review Flashcards

Comprehensive vocabulary flashcards covering evolutionary concepts, genetics, variation, Darwinian and Lamarckian mechanisms, speciation, reproductive isolation, and modern-day evolution.

Evolution

The processes of change in the genes that have transformed life on Earth from its earliest forms to the vast diversity that characterizes life today, broadly defined as change over time.

Biological Evolution

Genetic changes inherited over long periods of time in a population due to natural selection, ultimately resulting in the formation of new species.

Hypothesis

A possible prediction or explanation of phenomena formulated after observation, based on speculation and limited data, which can be either accepted or rejected.

Theory

A reliable scientific explanation of events in nature that is supported by facts, models, laws, and consistent results obtained via research and investigations by many scientists.

Fossil

An organism or the preserved remains, imprints, or footprints of an organism, usually preserved in rock.

Paleontology

The scientific study of fossils to determine the age, characteristics, and evolutionary relationships of extinct organisms.

Radiometric Dating

A method used to determine the age of fossils through the decay of radioactive elements.

Relative Dating

A method of determining the age of fossils based on their position in sedimentary layers, where older fossils occur at the bottom and more recent species occur on top.

Phylogenetic Tree

A branching diagram that illustrates the evolutionary relationships and common ancestry among different species.

Homologous Structures

Anatomical features in different species that share the same basic body plan or skeletal arrangement due to common ancestry, but are modified to perform different functions.

Descent with Modification

The principle that body plans of organisms have been modified across generations to adapt to different environments and modes of locomotion.

Biogeography

The study of the geographical distribution of individual species across different landmasses and regions of the world.

Pangaea

The ancient supercontinent that originally contained all modern continents before splitting apart as a result of continental drift.

Species

A group of organisms with similar characteristics that are capable of interbreeding to produce fertile offspring.

Population

A group of organisms of the same species living in the same area or habitat at a given time and capable of randomly interbreeding.

Crossing Over

The exchange of genetic material between non-sister chromatids of homologous chromosomes during Prophase I of meiosis, producing new combinations of alleles.

Chiasmata

The specific points of contact where non-sister chromatids overlap and exchange genetic material during crossing over.

Random Arrangement of Chromosomes

The independent alignment of homologous chromosome pairs along the equator during Metaphase I and II, creating gametes with varying mixes of parental chromosomes.

Point Mutation

A gene mutation resulting from the substitution or replacement of a single base in a codon, potentially altering a single amino acid in a protein.

Frameshift Mutation

A gene mutation caused by the addition or deletion of one or more bases in a codon, shifting the reading frame and changing all downstream codons to produce a different protein.

Continuous Variation

A type of variation in which a phenotypic characteristic changes gradually over a continuous range of values with no distinct categories, such as human height or weight.

Discontinuous Variation

A type of variation in which a characteristic falls into clear-cut, separate categories with no intermediate values, such as human ABO blood groups or tongue rolling.

Law of Use and Disuse

Lamarck's proposal that an organ or structure becomes enlarged and better developed the more it is used, while unused structures become reduced in size or disappear.

Inheritance of Acquired Characteristics

Lamarck's theory stating that physical modifications or traits developed by an individual during its lifetime can be directly passed on to its offspring.

Natural Selection

Darwin's mechanism of evolution stating that organisms with favourable characteristics suited to their environment are more likely to survive, reproduce, and pass those traits to subsequent generations.

Artificial Selection

Breeding practices conducted by humans to selectively develop organisms with specific desirable characteristics to satisfy human needs.

Punctuated Equilibrium

The hypothesis proposing that evolution involves long periods of little or no change (equilibrium) punctuated by short periods of rapid speciation, supported by gaps in transitional fossils.

Speciation

The evolutionary process that results in the formation of new, distinct species, often triggered when a population is split and separated by a physical barrier.

Extinction

The complete dying out or termination of a species when its members can no longer reproduce at replacement levels.

Reproductive Isolating Mechanisms

Behavioural patterns and physiological processes that prevent distinct but closely related species sharing the same habitat from successfully interbreeding.

Prezygotic Mechanisms

Reproductive isolating barriers that operate before fertilization to prevent mating or the formation of a zygote, including temporal, behavioural, and structural incompatibilities.

Postzygotic Mechanisms

Reproductive isolating barriers that operate after fertilization, leading to zygote mortality, poor hybrid fitness, hybrid sterility, or hybrid breakdown.

Temporal Isolation

A prezygotic barrier where closely related species are prevented from interbreeding because they reproduce during different seasons or times of the year.

Hybrid Sterility

A postzygotic isolating mechanism in which hybrid offspring survive to adulthood but are sterile and unable to produce gametes or offspring, such as a mule.

MDR-TB

Multi-Drug Resistant Tuberculosis; a strain of Mycobacterium tuberculosis that has mutated and developed resistance to the two most powerful first-line standard drugs.

XDR-TB

Extensively Drug-Resistant Tuberculosis; a dangerous strain resistant to the two most powerful first-line drugs and three or more of the six classes of second-line drugs.