Evolution is not the same as adaptation or natural selection. Natural selection is a mechanism, or cause, of evolution. Adaptations are physical or behavioral traits that make an organism better suited to its environment. Heritable variation comes from random mutations.

How does natural selection result in adaptations in a species? Individuals whose unique characteristics are well-suited for an environment tend to survive and reproduce more offspring.

Natural selection leads to adaptation, that is, to a population dominated by organisms that are anatomically, behaviorally, and physiologically well suited to survive and reproduce in a specific environment. Species become extinct because they can no longer survive and reproduce in their altered environment.

Part of the Darwin exhibition. Natural selection is a mechanism by which populations adapt and evolve. After numerous such breeding cycles, the better-adapted dominate. Nature has filtered out poorly suited individuals and the population has evolved.

• Deer Mouse.
• Warrior Ants.
• Peacocks.
• Galapagos Finches.
• Pesticide-resistant Insects.
• Rat Snake. All rat snakes have similar diets, are excellent climbers and kill by constriction.
• Peppered Moth. Many times a species is forced to make changes as a direct result of human progress.
• 10 Examples of Natural Selection. « previous.

The mechanism that Darwin proposed for evolution is natural selection. Because resources are limited in nature, organisms with heritable traits that favor survival and reproduction will tend to leave more offspring than their peers, causing the traits to increase in frequency over generations.

There are four mechanisms that make evolution work: mutation, gene flow, genetic drift and natural selection.

Genetic drift describes random fluctuations in the numbers of gene variants in a population. Both possibilities decrease the genetic diversity of a population. Genetic drift is common after population bottlenecks, which are events that drastically decrease the size of a population.

Factors influencing the genetic diversity within a gene pool include population size, mutation, genetic drift, natural selection, environmental diversity, migration and non-random mating patterns.

Virtually impossible. Given the mammals that already live in the water have never evolved traits to breath underwater, it suggests that land-based organisms that revert to water-living do not gain gills. For humans there is zero selection pressure to breath underwater, so there’s no basis for acquiring such a trait.

From a biological perspective, there is no such thing as devolution. The notion that humans might regress or “devolve” presumes that there is a preferred hierarchy of structure and function–say, that legs with feet are better than legs with hooves or that breathing with lungs is better than breathing with gills.

Anthropogenic. The Cambridge Project at Cambridge University says the “greatest threats” to the human species are man-made; they are artificial intelligence, global warming, nuclear war, and rogue biotechnology.