macroevolution and patterns of diversity

• Macroevolution is a general principle that life gets more diverse and complex with time as there are more opportunities for evolution to occur.
• Diversification after decimation is when increasing diversity is disrupted by extinctions. 
• Cambrian fauna was dominated by trilobites and arthropods that ate mostly mud. 
• Palaeozoic fauna was dominated by corals, brachiopods and predatory cephalopods. Fauna was tiered with different levels of life, reefs were common. 
• Modern fauna is dominated by bivalves, gastropods and vertebrates. Burrowing and predation is very common.