The Earth’s Biosphere

The Earth’s biosphere is basically everywhere on Earth that there is life. It includes the atmosphere, geosphere, and the hydrosphere. It is believed that life began in the oceans, and most life on the planet can thank the first photosynthetic organisms for producing the O₂ (oxygen) in the atmosphere. The largest animal on the planet, the blue whale, lives in the oceans and they eat some of the smallest organisms, krill. The Earth’s biosphere is broken down into biomes, the world’s major ecosystem types. The terrestrial biomes are usually classified by the main vegetation, such as, desert or tropical forest. The aquatic biomes are classified more by their physical environments, such as, lake or estuary. An ecosystem is a smaller area, and is a community of organisms living and interacting with each other and the environment of that area. A population is a group of individuals of the same species living in an area. A community refers to groups of populations of different species living in the same area. Ecology is the study of how organisms interact with each other and their environment. Ecosystem ecology is the study of the energy flow and the cycling of chemicals among the various biotic and abiotic components of an ecosystem.

There are three main domains of life. As scientists learn more, they make adjustments. There is the Domain Bacteria, which contains microscopic single-celled organisms. Domain Archaea, also contain microscopic single-celled organisms but these ones live in extreme environments, like hot springs of boiling water. The organisms in these two Domains are called Prokaryotes because of the structure of their cells and they both have many Kingdoms (which is the next breakdown in dividing similar organisms together). The third is Domain Eukarya which humans belong to. It has three Kingdoms; Plantae, Fungi, and Animalia. They are divided based on their mode of nutrition. Plants make their own food by photosynthesis and absorb chemical nutrients up through their roots. Fungi absorb dissolved nutrients from their surrounding; many are decomposers feeding on dead organisms and organic waste. Animals obtain their nutrients by ingestion; they eat other organisms (plants and or other animals). There is also a group of organisms called Protists (unicellular eukaryotes) that scientist are working on how to classify. Viruses are not considered a living organism because they cannot reproduce on their own or do any metabolic activities, such as breaking down food for energy. Viruses are tiny; smaller than bacteria. They are made up of nucleic acid (DNA and or RNA genome) surrounded by a protein coat, and considered an infectious particle as they need to infect a living cell to have the cell reproduce the virus. In Latin, virus means poison.

Reference: Campbell Biology 9th Edition; Reece, Urry, Cain, Wasserman, Minorsky, and Jackson