Students studying a population of salamanders in a vernal pool mark each salamander caught as it's entering the pool. During the first spring migration to the pool, the students mark 200 salamanders. The following year, they again capture 200 salamanders. Of these, 20 were from the previous year. Students use this information to calculate that they captured of the total population and that the total salamander population in their pool is about .

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.