Ecologists often build models to depict the relationships between organisms. In such models, an arrow is used to link two organisms in a relationship. The arrowhead is next to the organism that is affected. If the effect is positive, the arrow is labeled with (+), and if negative, then the label is (-). Which of the following models best illustrates the relationship of the Brazil nut tree and the other organisms associated with it?

Question

Quizplus · Accepted Answer

The arrow from the Brazil nut tree to the bees has a (+) label, indicating a mutualistic relationship where the tree provides bees with food in exchange for pollination. The arrow from the trees to the agouti has a (-) label, indicating a predator–prey relationship where the agouti eats the nuts. The arrow from the trees to the fungi has a (+) label, indicating a mutualistic relationship where the fungi help the tree absorb nutrients. The arrow from the birds to the trees has a (+) label, indicating a mutualistic relationship where the birds help spread the tree's seeds. The arrow from the wasps to the tree has a (-) label, indicating a parasitic relationship where the wasps lay their eggs in the nuts, damaging them.

Ecologists Often Build Models to Depict the Relationships Between Organisms