Animals
The organ level of organisation in animals can be first detected in flatworms and the more advanced phyla. The less-advanced taxons (like Placozoa, Porifera and Radiata) do not show consolidation of their tissues into organs.
Read more about this topic: Organ (anatomy)
Famous quotes containing the word animals:
“Man’s unique reward, however, is that while animals survive by adjusting themselves to their background, man survives by adjusting his background to himself.”
—Ayn Rand (1905–1982)
“There is no instant of time when one creature is not being devoured by another. Over all these numerous races of animals man is placed, and his destructive hand spares nothing that lives. He kills to obtain food and he kills to clothe himself; he kills to adorn himself; he kills in order to attack and he kills to defend himself; he kills to instruct himself and he kills to amuse himself; he kills to kill. Proud and terrible king, he wants everything and nothing resists him.”
—Joseph De Maistre (1753–1821)