But these mutations are organized, in a way. For example, let's say that 10,000 years after the most recent common ancestor, one of the mtDNA branches experienced a mutation. From that point on, that line of mtDNA would include that alteration. Another branch might experience a mutation in a different location. This alteration would also be passed on.
The pelagic zone can be contrasted with the benthic and demersal zones at the bottom of the sea. The benthic zone is the ecological region at the very bottom of the sea. It includes the sediment surface and some subsurface layers.Marine organisms living in this zone, such as clams and crabs, are called benthos.epending on the depth, the water column, rather like the Earth's atmosphere, can be divided into different layers. The pelagic zone occupies 1,330 million km 3 (320 million mi 3) with a mean depth of 3.68 km (2.29 mi) and maximum depth of 11 km (6.8 mi).
The abyssopelagic zone is located from 4,000 m to directly above the ocean floor and is a completely dark area home to colorless and blind animals. The deepest subzone is the hadopelagic zone, a name that originates from the Greek underworld Hades and refers to the ocean water in submarine trenches.Scientists generally classify the epipelagic and mesopelagic zones into what is known as the photic zone-or where light penetrates the water.nimals of The Epipelagic Zone. The zone best known to humans is where people can easily go scuba diving and many marine mammals are found. This area is packed with ocean life because of the sunlight that penetrates the surface.