Primary succession occurs when pioneer species move into an area that has no plants. Which organisms are common pioneer species?
A. Conifer trees and tall grasses with roots that loosen the soil
B. Mosses and lichens that can grow on rocky surfaces
C. Grasses and weeds that arrive as seeds carried by the wind and then germinate in rich soil
D. Vines and shrubs that help prevent the erosion of shallow soil
The correct answer is B. Mosses and lichens that can grow on rocky surfaces. These organisms are able to colonize barren or rocky areas because they are well-adapted to grow in harsh conditions. Mosses and lichens have the ability to stabilize soil, retain water, and provide nutrients to other plants, facilitating the establishment of more complex plant communities over time.
To arrive at this answer, we can use our knowledge of primary succession and the characteristics of pioneer species. Primary succession occurs in areas where there is no existing soil or vegetation, such as after a volcanic eruption or glacial retreat. Pioneer species are usually the first organisms to colonize these barren areas.
Option A mentions conifer trees and tall grasses with roots that loosen the soil. While these plants may be important in later stages of succession, they are not typically the first organisms to establish in a barren area.
Option C mentions grasses and weeds that arrive as seeds carried by the wind and germinate in rich soil. While this may occur in certain situations, primary succession typically occurs in areas with no or very poor soil, so it is less likely that rich soil would be available for these seeds to germinate in.
Option D mentions vines and shrubs that help prevent erosion of shallow soil. While these plants may be important in later stages of succession for their erosion control abilities, they are not typically the first organisms to establish in a barren area.
Therefore, the best answer is B. Mosses and lichens that can grow on rocky surfaces, as they are well-adapted to harsh conditions and can initiate the process of primary succession.