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A multicellular organism is an organism that consists of more than one cell, unlike unicellular organisms. [1] All species of animals , land plants and most fungi are multicellular, as are many algae , whereas a few organisms are partially uni- and partially multicellular, like slime molds and social amoebae such as the genus Dictyostelium .
Previous land-based life would probably have required other chemicals to attenuate ultraviolet radiation. [42] 580–542 Ma Ediacaran biota, the first large, complex aquatic multicellular organisms. [64] 580–500 Ma Cambrian explosion: most modern animal phyla appear. [65] [66] 550–540 Ma
Eukaryogenesis, the process which created the eukaryotic cell and lineage, is a milestone in the evolution of life, since eukaryotes include all complex cells and almost all multicellular organisms. The process is widely agreed to have involved symbiogenesis , in which an archeon and a bacterium came together to create the first eukaryotic ...
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 ...
The origin of the eukaryotic cell, or eukaryogenesis, is a milestone in the evolution of life, since eukaryotes include all complex cells and almost all multicellular organisms. The last eukaryotic common ancestor (LECA) is the hypothetical origin of all living eukaryotes, [ 70 ] and was most likely a biological population , not a single ...
Before early Cambrian diversification, [b] most organisms were relatively simple, composed of individual cells or small multicellular organisms, occasionally organized into colonies. As the rate of diversification subsequently accelerated, the variety of life became much more complex and began to resemble that of today. [12]
The researchers theorize that the lake likely teamed with life before its top permanently froze over long ago, and that these microbes are the living descendants of those ancient life forms. But ...
Photosynthetic organisms appeared between 3.2 and 2.4 billion years ago and began enriching the atmosphere with oxygen. Life remained mostly small and microscopic until about 580 million years ago, when complex multicellular life arose, developed over time, and culminated in the Cambrian Explosion about 538.8 million years ago. This sudden ...