The binomial nomenclature system was used to classify animals, but not until the 1700s when it was first formally introduced by Carl Linnaeus. In ancient times, plants and animals were instead usually just classified in terms of whether or not they were useful, or divided animals into categories such as 'domestic animals, wild animals, creeping animals, flying animals, sea animals'.
Research has shown that sea otters are doing their part by indirectly reducing the carbon dioxide (CO2) concentration in the atmosphere (Nichols et al. 2015). It starts with vast areas of kelp forests that, through photosynthesis, absorb atmospheric CO2 and release oxygen into the air.
I think photosynthesis is mainly from sunlight to make energy for food for the plants