5.3 – 1.8 MILLION: PLIOCENE

• Continents & oceans in current position
• North & South America connect via Isthmus of Panama, altering global temperatures & currents;
• Huge Gibraltar waterfall refills Mediterranean Sea;
• Climate cool, dry and seasonal;
• All modern plants & animals families present, land & sea;
• Grasslands, deciduous trees & shrubs spread as tropical forests recede;
• Land bridges cause migration & mixing of animal species;
• Carnivores thrive & diversify;
• First hominids – australopithecines – appear;
• Many upright, tool-using hominids by end of epoch.