Why Do Some Animals Get Gigantic?

Animals generally maintain a consistent size over time, but certain conditions can lead to gigantism. Insects and arthropods grew larger 300 million years ago due to increased atmospheric oxygen. Dinosaurs reached large sizes naturally but faced limits due to the square cube law, which they overcame with air sacs in their skeletons. Some land animals returned to water, allowing them to grow larger due to buoyancy and access to oxygen-rich air. Blue whales became the largest animals ever due to nutrient-rich ocean conditions and their ability to breathe air.

Describe how the buoyancy of water helped land animals grow larger.

What role did ocean currents play in the size increase of blue whales?