(2) (Of, or pertaining to) An organism that expresses the dominant gene (or allele). (ecology) (Of, or pertaining to) An organism or group of organisms having the most considerable influence or control in its ecological community among other organism.
Relevance. Rating Newest Oldest. Best Answer: Geological Period that lasted the longest: The Precambrian Era The Precambrian Era is the longest geological era beginning 4.5 billion years ago and lasting approximately 4 billion years. The Precambrian era is generally separated into two eons the first of which being the Archaean Eon.
Best Answer: What definition of era are you asking about? I'm supposing you mean eras in the geological time scale (since this is biology, and you're probably referring to the fossil record) In the formal geological time scale, there are ten eras (the Hadean Eon isn't subdivided into eras). These are Eoarchaen, Paleoarchaen, Mesoarchaen, Neoarchaen, Paleoproterozoic, Mesoproterozoic, Neoproterozoic, Paleozoic, Mesozoic, and Cenozoic (which is the current era). The longest would be the Paleoproterozoic Era, which spanned 900 million years. If you count the Precambrian Era (which isn't an era, technically...it is a supereon), then that would be longest, spanning 3958 million years. I would go with Paleoproterozoic Era. That's an official era, whereas Precambrian is just mistakenly called an era when it is actually a much longer span of time.