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A life form (also spelled life-form or lifeform) is an entity that is living, [1] [2] such as plants , animals , and fungi . It is estimated that more than 99% of all species that ever existed on Earth, amounting to over five billion species, [3] are extinct. [4] [5] Earth is the only celestial body known to harbor life forms. No form of ...
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. [1] This includes the study of body fossils, tracks ( ichnites ), burrows , cast-off parts, fossilised feces ( coprolites ), palynomorphs and chemical residues .
Adolf Seilacher has suggested that in the Ediacaran, animals take over from giant protists as the dominant life form. [99] The modern xenophyophores are giant single-celled protozoans found throughout the world's oceans, largely on the abyssal plain. Genomic evidence suggests that the xenophyophores are a specialised group of Foraminifera. [100]
With few exceptions, animals consume organic material, breathe oxygen, are able to move, reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described —of which around 1 million are insects —but it has been estimated there are over 7 million ...
The order Primates consists of 505 extant species belonging to 81 genera. This does not include hybrid species or extinct prehistoric species. Modern molecular studies indicate that the 81 genera can be grouped into 16 families; these families are divided between two named suborders and are grouped in those suborders into named clades, and some of these families are subdivided into named ...
Coelenterata is a term encompassing the animal phyla Cnidaria (corals, true jellies, sea anemones, sea pens, and their relatives) and Ctenophora (comb jellies). The name comes from Ancient Greek κοῖλος (koîlos) 'hollow' and ἔντερον (énteron) 'intestine', referring to the hollow body cavity common to these two phyla.
A team of international researchers has challenged the long-held belief that complex life forms first emerged on Earth 635 million years ago, presenting findings that show life may have existed ...
Possible senolytic agents are under preliminary research, including some which are in early-stage human trials. [6] [7] [clarification needed] The majority of candidate senolytic compounds are repurposed anti-cancer molecules, such as the chemotherapeutic drug dasatinib and the experimental small molecule navitoclax.