what is the life in the ocean like?
Most animal life during the Cambrian was aquatic with arthropods being the most dominant animals in the ocean.
Cambrian
Most animal life during the Cambrian was aquatic. Trilobites were once assumed to be the dominant life form at that time, but this has proven to be incorrect. Arthropods were by far the most dominant animals in the ocean, but trilobites were only a minor part of the total arthropod diversity. 
in which evolutionary force does competition play the biggest role UNANSWERABLE what is apex predator? An apex predator, also known as an alpha predator or top predator, is a predator at the top of a food chain, without natural predators. how is it conserved? By reintroducing them to nature . what effect does it have on community? Apex predators affect prey species' population dynamics and populations of other predators, both in aquatic and in terrestrial ecosystems. what is its history in evolution? Apex predators are thought to have existed since at least the Cambrian period, around 500 million years ago. what is this aforesaid period? It was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. what are its divisions? The Cambrian is divided into four epochs (series) and ten ages (stages). what are some flora found here? Although there were a variety of macroscopic marine plants no land plant (embryophyte) fossils are known from the Cambrian.
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Cambrian [SEP] Oceanic life
Most animal life during the Cambrian was aquatic. Trilobites were once assumed to be the dominant life form at that time, but this has proven to be incorrect. Arthropods were by far the most dominant animals in the ocean, but trilobites were only a minor part of the total arthropod diversity. What made them so apparently abundant was their heavy armor reinforced by calcium carbonate (CaCO), which fossilized far more easily than the fragile chitinous exoskeletons of other arthropods, leaving numerous preserved remains. The period marked a steep change in the diversity and composition of Earth's biosphere. The Ediacaran biota suffered a mass extinction at the start of the Cambrian Period, which corresponded with an increase in the abundance and complexity of burrowing behaviour.