Ainimals is multicellular, eukaryotic organisms o the kinrick Animalia (forby cried Metazoa). Aw ainimals are motile, meanin thay can muiv spontaneously an independently, at some pynt in thair lifes. Thair body plan hidnerly becomes fixed as thay develop, tho some unnergang a process o metamorphosis later on in thair lifes. Aw ainimals is heterotrophs: thay maun ingest ither organisms or thair products for sustenance.
Maist kent ainimal phyla appeared in the fossil record as marine species in the Cambrian explosion, aboot 542 million year syne. Ainimals is dividit intae various sub-groups, some o whilk is: vertebrates (birds, mammals, amphibians, reptiles, fish); molluscs (clams, eysters, octopuses, ink-fish, snails); arthropods (meggie-mony-feets, jennie-hunder-feets, insects, speeders, scorpions, keavies, lapsters, saund-clapper); annelids (yirdwirms, gells); spoonges; an loch-livers.
References[eedit | eedit soorce]
- Harzsch, S.; Müller, C. H. (18 Mey 2007). "A new look at the ventral nerve centre of Sagitta: implications for the phylogenetic position of Chaetognatha (arrow worms) and the evolution of the bilaterian nervous system". Frontiers in Zoology. 4: 14. PMC 1885248. PMID 17511857. doi:10.1186/1742-9994-4-14.