Final answer:
The biosphere refers to the part of Earth where all life exists, traversing various ecosystems, including the deep ocean and high altitudes. It covers from the oceanic abyss to the atmosphere, hosting a wide array of life and is critical for Earth’s photosynthesis, particularly within ocean ecosystems.
Step-by-step explanation:
The biosphere encompasses all living organisms on Earth, extending through the oceans, land, and air. It includes regions such as the lithosphere (earth's crust), hydrosphere (bodies of water), and atmosphere (surrounding layer of gas). The biosphere comprises various ecosystems, from the ocean depths where light doesn't penetrate, to the high altitudes where flying animals dwell. It plays an integral role in supporting life, particularly ocean ecosystems, which cover 75 percent of Earth's surface and perform a significant portion of the world’s photosynthesis, thanks to abundant phytoplankton.
Ocean ecosystems are categorized into shallow water environments, replete with biodiversity like coral reefs, and deep ocean ecosystems that host a range of marine life despite the lack of sunlight. The biosphere is vast, covering areas from about 11,000 meters below to 15,000 meters above sea level, including even the most remote and extreme environments. Considering the Gaia hypothesis, the biosphere is not only a collection of all life forms but also functions as a single entity, being itself a significant organism within the cosmos.
The various levels of biological organization, such as cells, tissues, organs, organism, populations, communities, ecosystems, and biomes, all find their place within the all-encompassing biosphere which, in its entirety, supports the rich biodiversity seen on our planet.