Lewis/Life - Review of Key Concepts

Review of Key Concepts - Chapter 18

Biological evolution is change in the genetic characteristics of a population, which can lead to new species. Evolution has occurred in the past and is ongoing.
Biogeography considers the physical distribution of organisms. Islands provide evidence of evolution because their geographical isolation separates individuals with particular combinations of traits from ancestral organisms. Interdependence between species illustrates coevolution.
Evolution consists of large-scale, species-level changes of macroevolution and gene-by-gene changes of microevolution.
Geology laid the groundwork for evolutionary thought. The principle of superposition states that lower rock strata are older, suggesting a time frame for fossils within them. Some people explained the distribution of rock strata with Neptunism (a single flood) or mosaic catastrophism (a series of floods), but uniformitarianism (continual remolding of the earth's surface) became widely accepted.
Charles Darwin observed the distribution of organisms in many diverse habitats as naturalist aboard the HMS Beagle. Afterwards, he synthesized his theory of the origin of species by means of natural selection.
The theory of natural selection states that individuals least adapted to their environments are less likely to survive to produce fertile offspring. Better adapted individuals with different variations of inherited traits reproduce more successfully and flourish. Eventually, enough changes accumulate that members of the population can no longer mate with members of the ancestral population, and a new species arises. Natural selection does not produce perfection, but adaptation.
Sexual selection is a form of natural selection in which certain inherited traits make an individual more likely to mate and produce viable offspring.
Emerging and returning infectious illnesses and increasing resistance of bacteria to antibiotic drugs illustrate evolution in action.