Around 250 million years ago, Earth's continents were fused into a single landmass and its climate was far more extreme than today. The cause of what followed was a massive, geologically rapid release of volcanic carbon dioxide. During this period, called the End-Permian mass extinction, global temperatures rose sharply within a geologically short span, acidifying oceans and collapsing most marine food chains. The event lasted for tens of thousands of years, until the excess carbon was gradually reabsorbed. Life on Earth survived, indeed it eventually diversified again, but it looked drastically different afterward.

Based on the above passage, the following assumptions have been made:

1. Rapid global warming has a bearing on the planet's biological evolution.

2. The fusing of continents causes the release of huge quantities of volcanic carbon into the atmosphere.

3. Increased warming of Earth's atmosphere can change the composition of its flora and fauna.

4. Present-day human-made global warming will finally lead to conditions identical to those of 250 million years ago.

Which of the assumptions given above are valid?