Mutations can be considered as one of the raw materials of evolution because they:
1) contribute to new variations in organisms
2) are usually related to the environment in which they appear
3) are usually beneficial to the organism in which they appear
4) usually cause species of organisms to become extinct

Which of the following observation darwin shape his concept of descent with modification? a) species diversity declines farther from the equator. b) fewer species live on islands than on the nearest continents. c) birds live on islands located farther from the mainland than the bird's maximum nonstop flight distance. d) south american temperate plants are more similar to the tropical plants of south america than to the temperate plants of europe. e) earthquakes reshape life by causing mass extinctions.