Module 10: Evolution - Complete Review Flashcards

Vocabulary flashcards covering the entirety of Module 10: Evolution lecture notes.

Abiotic Synthesis

The non-biological origin of organic molecules under early Earth conditions, where self-replicating molecules and building blocks likely appeared together in early proto-cells.

Vesicle

A fluid-filled compartment enclosed by a membrane, whose formation increases when organic molecules and water are added to clay produced by volcanic ash.

Ribozymes

RNA enzymes that can catalyse chemical reactions, including the addition of ribonucleotides to a complementary RNA strand, supporting the hypothesis that RNA evolved before DNA.

Stromatolites

Layered rocks formed when certain prokaryotes bind sediment together, providing the earliest fossil evidence of life dated to $3.5\text{ billion}$ years ago.

Oxygen Revolution

A dramatic increase in atmospheric oxygen around $2.4\text{ billion}$ years ago caused by bacterial photosynthesis, which destroyed many anaerobic prokaryote groups and selected for cellular respiration.

Endosymbiont Hypothesis

The theory that eukaryotic cell features and organelles arose through the internalisation of prokaryotes, supported by mitochondria having similar inner membrane structures, division, and ribosomes to prokaryotes.

16S rRNA

The small subunit of ribosomal RNA whose sequence comparison by Woese demonstrated that eukaryotes are more closely related to archaea than to bacteria.

Pangaea

A single supercontinent formed about $250\text{ million}$ years ago that later split into Laurasia and Gondwana due to continental drift, driving extinctions and environmental changes.

Permian Mass Extinction

A mass extinction event around $250\text{ million}$ years ago caused by volcanic activity, rising carbon dioxide, and global warming that claimed about $96\%$ of marine animal species.

Cretaceous Mass Extinction

A mass extinction event $65.5\text{ million}$ years ago likely caused by a large comet impact, which extinguished over half of all marine species and all terrestrial dinosaurs.

Adaptive Radiation

The process where groups of organisms form many new species with adaptations that allow them to fill different ecological niches, such as mammals expanding after dinosaur extinction.

Chordates

Bilaterally symmetrical animals possessing a hollow nerve cord, a notochord, pharyngeal slits, and a muscular post-anal tail.

Notochord

A flexible rod located between the digestive tube and the nerve cord in chordates.

Tiktaalik

A fossil discovered in 2006 representing a missing link between fish and tetrapods, possessing fish traits (scales, fins, gills, lungs) and tetrapod traits (ribs, neck, shoulders, and fin bones like humerus, radius, and ulna).

Palaeoanthropology

The scientific study of human origins and fossil hominins.

Hominins

Species that are more closely related to humans than to chimpanzees, featuring reduced canine teeth, bipedalism, tool use, and expanding brain sizes.

Homo ergaster

A hominin species represented by a $1.7\text{ million}$-year-old fossil of a young male from Kenya who was fully bipedal, had a large brain, and showed reduced sexual dimorphism.

Neanderthals

A hominin species living in Europe by $350,000$ years ago that had brains larger than modern humans, buried their dead, used tools, and interbred with Homo sapiens before going extinct around $28,000$ years ago.

CPT1A Gene

A gene involved in fatty acid oxidation with a mutation found at a $68\%$ frequency in Siberian populations, providing a selective advantage in extreme cold (below $-70^\circ\text{C}$) and high-fat diets despite increasing infant mortality elsewhere.

Devil Facial Tumour Disease

A contagious cancer threatening the Tasmanian devil with extinction due to a lack of genetic variation at the immune response locus required to recognise and reject cancer cells.

Hardy Weinberg Equilibrium

The state of a non-evolving population in which allele and genotype frequencies remain constant across generations under five conditions: no mutation, random mating, no natural selection, extremely large population, and no gene flow.

Microevolution

A change in allele frequencies within a population over time, caused by natural selection, genetic drift, or gene flow.

Genetic Drift

A random change in allele frequencies in a population over time that does not occur due to natural selection and can fix harmful alleles or reduce variation in small populations.

Founder Effect

A type of genetic drift occurring when a few isolated individuals establish a new population with a gene pool that differs from the original population, such as increased Huntington disease frequency in Tasmania.

Population Bottleneck

A sudden reduction in population size and allele diversity caused by environmental catastrophes or disease outbreaks.

Gene Flow

The transfer and movement of alleles between different populations through migration and interbreeding, which tends to homogenise populations.

Directional Selection

A mode of natural selection that increases the frequency of traits at one end of a normal distribution, shifting the population mean, as seen in cliff swallow body size.

Stabilising Selection

A mode of natural selection that selects against extreme phenotypes at both ends of a distribution, narrowing variation, as seen in human birth weights.

Disruptive Selection

A mode of natural selection that selects against intermediate phenotypes and favours both extreme ends of a distribution, which can lead to speciation.

Heterozygote Advantage

A form of balancing selection where heterozygous individuals have higher fitness than both homozygotes, such as sickle cell trait carriers having protection against malaria.

Heterochrony

An evolutionary change in the rate or timing of developmental events, such as changes in fetal jaw growth producing smaller adult jaws in humans relative to chimpanzees.

Allopatric Speciation

Speciation caused by geographic isolation that physically separates a population, such as different squirrel species on opposite sides of the Grand Canyon.

Sympatric Speciation

Speciation occurring without geographic isolation, driven by factors such as polyploidy, sexual selection, or switching habitats.

Hybrid Zone

A geographic area where species with incomplete reproductive barriers meet and interbreed, producing offspring of mixed ancestry such as Bombina toads.

Macroevolution

Evolutionary change above the species level, including the emergence of new groups through multiple speciation events and mass extinction impacts.

Acquisition of Acquired Characteristics

An incorrect hypothesis proposed by Lamarck stating that traits acquired or modified over an individual's lifetime are passed on to offspring.

Natural Selection

The mechanism of evolution where individuals with favourable heritable alleles survive and reproduce at higher rates in a specific environment, altering allele frequencies across generations.

Adaptation

A heritable genetic trait that enhances an individual's survival and reproductive success in a given environment.

Methicillin-Resistant Staphylococcus aureus

A genetic variety of Staphylococcus aureus (MRSA) that survived antibiotic treatment by synthesizing its cell wall using an alternative protein.

rpoB Gene

A gene in Mycobacterium tuberculosis that developed a point mutation in RNA polymerase, preventing rifampin from binding and granting antibiotic resistance.

Homology

Anatomical, developmental, structural, or genetic similarity among organisms resulting from common ancestry.

Vestigial Structures

Remnants of traits that served key functions in ancestors but no longer serve a primary function in modern organisms, such as the human tailbone and goose bumps.

Radiometric Dating

A technique using the half-life decay of radioactive isotopes, such as carbon-14 to carbon-12 ratios up to $75,000$ years, to estimate the relative age of fossils.

Biogeography

The study of the geographic distributions of plant and animal species across the Earth.

Artificial Selection

Selective breeding by humans to change species over time, such as producing broccoli, cabbage, brussels sprouts, and kale from wild mustard.

Acclimation

A non-heritable phenotypic change in an individual organism due to environmental factors that does not alter its genotype or pass to offspring.