Evolutionary Biology

• Evolution is the change in the genetic makeup of populations, not individuals, driven by mutation.

Evolutionary Biology

• Charles Darwin's "On the Origin of Species" provided evidence for descent with modification, where traits change over generations.
• Natural selection is the process where individuals with favorable inherited traits survive and reproduce more.
• Microevolution involves changes in allele frequencies within a population over generations.
• Allele frequency is how common an allele is in a population.
• Macroevolution is the emergence of new species (speciation) due to large-scale genetic changes.

Development of Evolutionary Thoughts

• Georges Cuvier (1769-1832) founded paleontology and demonstrated different rock strata in the Paris basin had unique mammal fauna.
• Cuvier proposed catastrophism: Earth's landscape shaped by violent geologic events, with stratum boundaries representing catastrophes where new species appeared and others disappeared.
• Charles Lyell (1797-1875) proposed the "Theory of Uniformity," where gradual changes shaped Earth's surface.
• The law of superposition states that younger rocks are on top, and older rocks are at the bottom.
• Jean-Baptiste Lamarck (1744-1829) suggested organisms evolve due to a drive for complexity, moving from dead matter to human "perfection."
• Lamarck also believed species change into other species, rather than going extinct.
• Lamarck's theory of use and disuse stated that environmental pressures cause an internal requirement for change.
• Lamarck's theory of inheritance of acquired characteristics suggested organisms pass traits acquired during their lifetime to offspring.
• Thomas Malthus (1766-1834) proposed that population growth leads to disease, famine, and war due to competition for limited resources, defining "carrying capacity."
• Carrying Capacity is the maximum number of individuals an environment can support.
• Alfred Russel Wallace (1823-1913) independently developed a theory of evolution by natural selection similar to Darwin's.
• Charles Darwin (1808-1882) proposed species change, divergent species share common ancestors, and natural selection explains changes through differential survival and reproduction based on traits.
• Gregor Mendel (1822-1884) discovered the basic principles of heredity, experimenting with garden peas.
• The Law of Dominance: Only the dominant allele will be expressed when two alleles are present.
• The Law of Segregation: Each gamete receives only one copy of a gene when an individual produces gametes.
• The Law of Independent Assortment: Alleles of different genes assort independently during gamete formation.

Evidence of Evolution and Microevolution

• Biogeography studies patterns in the geographic distribution of communities, revealing patterns of past evolution in species distributions.
• Fossils are remains of organisms that lived long ago and show a progression of evolution.
• DNA analysis is the most detailed evidence for evolution, showing relationships between species.
• DNA analysis indicates all species share a common ancestor (LUCA).
• Closely related species have more similar DNA, suggesting recent common ancestry.
• Comparative anatomy analyzes morphological similarities among organisms.
• Homologous structures are similar due to common descent.
• Analogous structures are similar but not due to common ancestry.
• Vestigial structures are remnants of features that served a function in ancestors.
• Embryology shows animals have similar embryonic development patterns due to master regulators.
• Each population possesses a gene pool, which includes all alleles for all loci present in the population.
• The Hardy-Weinberg equilibrium states allele frequencies remain constant unless evolutionary forces act upon the population.
• Deviations from Hardy-Weinberg equilibrium indicate evolution.
• Gene flow (migration) is the movement of alleles between populations when individuals move and mate.
• Gene flow is a potent agent of change.
• Genetic drift is the change in allele frequencies due to chance, usually in small populations.
• The bottleneck effect occurs when a population size is suddenly reduced.
• The founder effect occurs when a small group establishes a new colony.
• Natural selection is where environmental conditions determine which individuals produce the most offspring.
• Differential survival occurs due to food availability, predators, diseases, and climate change.
• Artificial selection occurs when breeders select for desired characteristics.
• Sexual selection is when certain individuals have an advantage over others of the same sex in reproduction.
• Mutation is a change in DNA sequence, creating new alleles and is the ultimate source of variation.
• Nonrandom mating is when individuals with certain genotypes mate more commonly than expected, influenced by phenotypic differences based on underlying genotypic differences.