Water and Planetary Habitability

Water resources refers to natural resources of water that are potentially useful as a source of water supply. About 97% of the water on the Earth is mainly salt water and only around 3% is fresh water; approximately around two thirds of this is frozen in glaciers and polar ice caps. The remaining unfrozen freshwater can be found mainly as groundwater, only a small fraction is present above the ground or in the air. Natural sources of fresh water comprises surface water, under river flow, groundwater and frozen water. Artificial sources of fresh water might include treated wastewater (reclaimed water) and also desalinated seawater. On the surface of the Earth, the distribution of water is generally unequal. Fresh water comprises only 3% of the water on the surface; the rest 97 percent is in the ocean. Freshwater is found in glaciers 69 percent of the time, underground 30 percent of the time, and in rivers, lakes and swamps less than 1% of the time. To put it another way, only 1% of the water on the surface of the Earth is usable by humans, while 99 percent of the useful quantity is underground. Because the oceans hold 97 percent of the planet’s water, only 3% is fresh water, or water with low salt content. Greenland’s huge ice sheets and glaciers retain the majority of fresh water as ice. A reservoir is a place where water is stored, such as an glacier, ocean, pond, or even the atmosphere. A water molecule may travel through a reservoir fast or remain for an extended period of time. The residence time of a molecule in a reservoir is measured in seconds. Because the oceans hold 97 percent of the planet’s water, only 3% water is with low salt content or fresh water. Greenland’s huge ice sheets and glaciers retain the majority of fresh water as ice. A reservoir is a place where water is stored, such as an glacier, ocean, pond, or even the atmosphere. A water molecule may travel through a reservoir fast or remain for an extended period of time. The residence time of a molecule in a reservoir is measured in seconds.

Habitable Zones

The orbital region around a star in which an Earth-like planet with liquid water on its surface and the potential to support life can be found. Because liquid water is necessary for all life on Earth, the notion of a habitable zone is founded on the assumption that alien life would require it as well. This is a fairly conservative (but observationally useful) definition, because a planet’s surface temperature is affected by factors such as atmospheric greenhouse gases, reflectance, and atmospheric or oceanic circulation, in addition to its proximity to its star. Internal energy sources like tidal heating and radioactive decay can also heat a planet’s surface to the point where water melts. These energy sources can also keep underground liquid water reserves afloat, allowing a planet to harbour life even if it is beyond of its star’s habitable zone. As for example, Earth comprises a robust underground biosphere , however it is virtually entirely made up of basic species that can thrive in low-oxygen situations. Europa, Jupiter’s moon, has a liquid water ocean tens of kilometres beneath its surface that could support life.

Life On Earth

Life is a feature that distinguishes physical entities that have biological processes, such as signalling and self-sustaining mechanisms, from those that do not, either because such functions have stopped (they have died) or as they never had such type of functions and are classified as inanimate. Plants, fungi, protists, archaea, bacteria and mammals are examples of various types of life. Biology is the study of living things. Earth would not have been a pleasant home for animals for most of its history if it had been devoid of oxygen and abundant in methane. The oldest known living forms were comprises of very minute organisms (microbes) that left traces of their existence in rocks dating back 3.7 billion years. The signals were composed of a form of carbon molecule that is found in living beings. Microbes leaves their evidence in the hard structures (“stromatolites”) they created, which date back 3.5 billion years. Stromatolites form when bacteria form sticky mats that collect and bind sediments into layers. Even when the microorganisms die off, minerals precipitate within the layers, forming long-lasting structures. Today’s rare live stromatolite reefs are being studied by scientists in order to gain a deeper understanding of Earth’s earliest life forms.

The First Animal

The first mammals originated from these clusters of specialised, cooperative cells some 800 million years ago, according to DNA evidence. Sponges were among the first animals discovered. While sponge chemical components have been found in rocks dating back 700 million years, molecular evidence suggests sponges evolved considerably earlier. Although oxygen levels inside the ocean were really low compared to today’s levels, sponges can survive in low-oxygen environments. They require oxygen to metabolise, much like other animals, but they don’t require much because they are not extremely active. They eat by collecting food particles from water that is pushed through their body by specialised cells while they sit stationary. A sponge’s basic body plan comprises of layers of cells around water-filled spaces, which are supported by hard skeletal components. The evolution of increasingly sophisticated and diverse body designs would eventually contribute to the creation of various animal groups.

The instructions for assembling an animal’s body design are stored in its genes. Some genes function like orchestra conductors, directing the activity of most other genes at specific locations and There is information that parts of instructions for complex bodies were included even in the first animals, even if they were not immediately carried out. Sponge skeletons allowed them to become the first reef builders on the planet. times to ensure that the components are correctly assembled.

Conclusion

Living species can be found from the poles to the equator, from the ocean floor to several miles in the air, from cold waters to arid valleys, undersea thermal vents and groundwater hundreds of feet beneath the Earth’s surface. Living species on Earth have varied and adapted to practically every setting imaginable over the last 3.7 billion years or so. Life’s diversity is certainly astonishing, however all living organisms share some commonalities. DNA is the replicator molecule found in all living beings. In addition, all living creatures have some mechanism for turning DNA information into molecules that are utilised to construct cellular machinery from lipids, proteins and carbohydrates.