Generalize why maintaining biodiversity has a direct economic value to humans.

Because if there are no animals we can't live, we purposely mix breeds maintaining more than one resource. Maintaining biodiversity has a direct economic value to humans, as well as indirect economic value because our ecosystem is affected by any imbalances in the environment. For example, a lack of trees will mean we don't have enough oxygen to breath. A lack of fish will mean many animals that feed of sea creatures will die.

He used pea plants to study the patterns of heredity.