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Bacteria are prokaryotic microorganisms that can either have a bacilli, spirilli, or cocci shape and measure between 0.5-20 micrometers. They were one of the first living cells to evolve [9] and have spread to inhabit a variety of different habitats including hydrothermal vents, glacial rocks, and other organisms.
Stupendemys appears in the fossil record as the largest freshwater turtle, first modern elephants, giraffes, zebras, lions, rhinoceros and gazelles appear in the fossil record 3.6 Ma Blue whales grow to modern size. 3 Ma Earliest swordfish. 2.7 Ma Paranthropus evolves. 2.5 Ma Earliest species of Arctodus and Smilodon evolve. 2 Ma
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. [1] [2] [3] The similarities among all known present-day species indicate that they have diverged through the ...
Parasite virulence is the level of harm a host endures due to a virus, bacteria, or parasite. [1] The way a host lives contributes heavily to how their body will react to pathogens. If an organism lives a moderately healthy lifestyle, including its diet, physical activity, and decreased stress, its chances of fighting off infectious diseases ...
A microorganism, or microbe, [a] is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells.. The possible existence of unseen microbial life was suspected from ancient times, such as in Jain scriptures from sixth century BC India.
Host–parasite coevolution is a special case of coevolution, where a host and a parasite continually adapt to each other. This can create an evolutionary arms race between them. A more benign possibility is of an evolutionary trade-off between transmission and virulence in the parasite, as if it kills its host too quickly, the parasite will ...
The ARMAN are a group of archaea discovered in acid mine drainage in the early 2000s. The classification of archaea, and of prokaryotes in general, is a rapidly moving and contentious field. Current classification systems aim to organize archaea into groups of organisms that share structural features and common ancestors. [22]
A fish parasite, the isopod Cymothoa exigua, replacing the tongue of a Lithognathus. Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. [1]