1/25/2024 0 Comments Animals and plants are composed ofThis gives them their name, from the Greek εὖ ( eu, "well" or "good") and κάρυον ( karyon, "nut" or "kernel", here meaning "nucleus"). The defining feature of eukaryotes is that their cells have nuclei. Eukaryotes range in size from single cells to organisms weighing many tonsįurther information: Cell (biology) § Eukaryotic cells Nucleus.Eukaryotes represent a small minority of the number of organisms, but, as many of them are much larger, their collective global biomass (468 gigatons) is far larger than that of prokaryotes (77 gigatons), with plants alone accounting for over 81% of the total biomass of Earth. Eukaryotic cells are typically much larger than those of prokaryotes-the bacteria and the archaea-having a volume of around 10,000 times greater. The multicellular eukaryotes include the animals, plants, and fungi, but again, these groups too contain many unicellular species. Many eukaryotes are unicellular the informal grouping called protists includes many of these, with some multicellular forms like the giant kelp up to 200 feet (61 m) long. Eukaryotes can reproduce both asexually through mitosis and sexually through meiosis and gamete fusion ( fertilization).Įukaryotes are organisms that range from microscopic single cells, such as picozoans under 3 micrometres across, to animals like the blue whale, weighing up to 190 tonnes and measuring up to 33.6 metres (110 ft) long, or plants like the coast redwood, up to 120 metres (390 ft) tall. Unicellular eukaryotes are sometimes called protists. In comparison, prokaryotes are typically unicellular. Eukaryotes may be either unicellular or multicellular. A second episode of symbiogenesis with a cyanobacterium created the plants, with chloroplasts.Įukaryotic cells contain membrane-bound organelles such as the nucleus, the endoplasmic reticulum, and the Golgi apparatus. The leading evolutionary theory is they were created by symbiogenesis between an anaerobic Asgard archaean and an aerobic proteobacterium, which formed the mitochondria. Eukaryotes emerged approximately 2.2 billion years ago, during the Proterozoic eon, likely as flagellated cells. This implies that there are only two domains of life, Bacteria and Archaea, with eukaryotes incorporated among the Archaea. The eukaryotes seemingly emerged in the Archaea, within the Asgard archaea. Eukaryotes represent a small minority of the number of organisms, but given their generally much larger size, their collective global biomass is much larger than that of prokaryotes. They constitute a major group of life forms alongside the two groups of prokaryotes: the Bacteria and the Archaea. All animals, plants, fungi, and many unicellular organisms are eukaryotes. The eukaryotes ( / j uː ˈ k ær i oʊ t s, - ə t s/) constitute the domain of Eukarya, organisms whose cells have a membrane-bound nucleus. ( Chatton, 1925) Whittaker & Margulis, 1978
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