Short answers, pulled from the story.
Evolution is the change in the heritable characteristics of biological populations over successive generations. This process has shaped every living thing from the smallest bacterium to the largest whale through mechanisms like genetic drift and natural selection.
The scientific theory of evolution by natural selection was conceived independently by two British naturalists, Charles Darwin and Alfred Russel Wallace, in the mid-19th century. Darwin first set out the theory in detail in his book On the Origin of Species, published in 1859.
All life on Earth shares a last universal common ancestor known as LUCA, which lived approximately 3.5 to 3.8 billion years ago. The fossil record provides a tangible history of life's journey from early biogenic graphite to microbial mat fossils to fossilised multicellular organisms.
Natural selection is the process by which traits that enhance survival and reproduction become more common in successive generations of a population. Organisms with traits that give them an advantage over their competitors are more likely to pass on their traits to the next generation than those with traits that do not confer an advantage.
The four primary geographic modes of speciation are allopatric speciation, peripatric speciation, parapatric speciation, and sympatric speciation. Allopatric speciation occurs in populations initially isolated geographically, while sympatric speciation involves species diverging without geographic isolation or changes in habitat.