Final answer:
Elephants obtain nitrogen by consuming plants that assimilate nitrogen through biological nitrogen fixation, with soil bacteria and legumes playing a key role in converting atmospheric nitrogen to ammonia, which plants use to synthesize amino acids and proteins.
Step-by-step explanation:
How Elephants Get Their Source of Nitrogen
Elephants, like other heterotrophs, get their nitrogen by consuming plants. These plants obtain nitrogen through a process called biological nitrogen fixation (BNF). BNF is the conversion of atmospheric nitrogen, which is primarily N₂, into ammonia (NH₃) by soil bacteria and legumes. The fixed nitrogen is then incorporated into amino acids within plants and can be consumed by animals, such as elephants, as part of their diet.
Specifically, rhizobium bacteria living symbiotically in the root nodules of legume plants, like peas and beans, fix nitrogen from the atmosphere. These bacteria convert nitrogen into a form that plants can use, such as ammonia, which is then assimilated into amino acids and proteins within the plant. When elephants eat these plants, they ingest the nitrogen-containing compounds, providing them with the essential nutrient. Additionally, nitrifying bacteria in the soil can convert ammonia into nitrate (NO₃-), another form of nitrogen that plants can absorb and utilize. Therefore, elephants indirectly depend on the activity of nitrogen-fixing and nitrifying bacteria for their nitrogen intake.