AP BIOLOGY

Detailed explanation-1: -Natural selection is a mechanism of evolution. Organisms that are more adapted to their environment are more likely to survive and pass on the genes that aided their success. This process causes species to change and diverge over time.

Detailed explanation-2: -The earliest life forms we know of were microscopic organisms (microbes) that left signals of their presence in rocks about 3.7 billion years old.

Detailed explanation-3: -Bacterial evolution is the process of heritable change in populations of bacteria over multiple generations. It occurs through mechanisms including natural selection and genetic drift, and can result in adaptations to environmental change or host immunity.

Detailed explanation-4: -It is likely that eukaryotic cells, of which humans are made, evolved from bacteria about two billion years ago. One theory is that eukaryotic cells evolved via a symbiotic relationship between two independent prokaryotic bacteria.