Human Evolution

Hominins underwent massive physiological changes as they evolved an migrated out of Africa

Early Milestones

Early hominids were using Oldowan stone tools to access new food sources like meat.

The harnessing of fire

Fire kept nocturnal predators at bay, provided warmth, and critically, allowed for cooking. The rapid evolution resulted in rapid brain growth

Melanin and UV Radiation

Early humans lost thick body hair to regulate temperature via sweatglands.

Melanin acts as a shield, absorbing up to 99% of harmful UV radiation and dissipating it as harmless heat.

Vitamin D and lighter skin

genetic mutations for lighter skin were naturally selected because they allowed the skin to absorb the limited UV radiation available

Climate-Driven Anatomy

Early humans living in the heat evolved narrow bodies with long legs to stay cool and travel efficiently.

Conversely, those migrating to colder climates evolved shorter, wider, and stockier bodies to conserve heat

Prokaryotes

are small, lack a nucleus, and contain circular DNA

Eukaryotes

Are larger, contain a nucleus harboring linear DNA, and have specialized membrane-bound organelles

Chloroplasts

Aeukaryotic cell that already possessed mitochondria engulfed a photosynthetic cyanobacterium. this bacterium retained its ability to convert solar energy into sugars and eventually evolved into the chloroplast.