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An echinoderm (/ ɪ ˈ k aɪ n ə ˌ d ɜːr m, ˈ ɛ k ə-/) [3] is any deuterostomal animal of the phylum Echinodermata (/ ɪ ˌ k aɪ n oʊ ˈ d ɜːr m ə t ə /), which includes starfish, brittle stars, sea urchins, sand dollars and sea cucumbers, as well as the sessile sea lilies or "stone lilies". [4]
Homo (from Latin homō 'human') is a genus of great ape (family Hominidae) that emerged from the genus Australopithecus and encompasses only a single extant species, Homo sapiens (modern humans), along with a number of extinct species (collectively called archaic humans) classified as either ancestral or closely related to modern humans; these include Homo erectus and Homo neanderthalensis.
This is about the same size as the modern bonobo and female chimpanzee brain; it is somewhat smaller than the brain of australopithecines like Lucy (400 to 550 cm 3) and slightly over a fifth the size of the modern Homo sapiens brain.
A new comparison of the human and chimpanzee genomes suggests that after the two lineages separated, they may have begun interbreeding... A principal finding is that the X chromosomes of humans and chimpanzees appear to have diverged about 1.2 million years more recently than the other chromosomes. The research suggests:
Another feature present in both the Hemichordata and Chordata is pharyngotremy — the presence of spiracles or gill slits into the pharynx, which is also found in some primitive fossil echinoderms . [16] [17] A hollow nerve cord is found in all chordates, including tunicates (in the larval stage). Some hemichordates also have a tubular nerve cord.
The Hominidae (/ h ɒ ˈ m ɪ n ɪ d iː /), whose members are known as the great apes [note 1] or hominids (/ ˈ h ɒ m ɪ n ɪ d z /), are a taxonomic family of primates that includes eight extant species in four genera: Pongo (the Bornean, Sumatran and Tapanuli orangutan); Gorilla (the eastern and western gorilla); Pan (the chimpanzee and the bonobo); and Homo, of which only modern humans ...
Ctenocystoids are likely among the most basal stem-group echinoderms. [1] They have also been interpreted as aberrant blastozoans and as stem-group hemichordates . [ 7 ] [ 8 ] The presence of stereom plates indicates that they most likely belong to the echinoderm total group, rendering a hemichordate affinity unlikely.
The Eocrinoidea are an extinct class of echinoderms that lived between the Early Cambrian and Late Silurian periods. They are the earliest known group of stalked, arm-bearing echinoderms, and were the most common echinoderms during the Cambrian.