Our Evolving Planet. Life Evolves – It Changes. Everything on Earth that has ever lived is connected through, and is the result of, evolution . It’s a process that’s been happening since the first tiny life forms appeared some four billion years ago.
Organic compounds may have been carried to Earth aboard meteorites from outer space.
Scientists who study ancient meteorites have discovered that some contain organic compounds, life’s building blocks.
Such meteorites may well have brought the raw material of life to Earth.
1. Beneath the ocean floor, chemical-rich water is heated by molten rock. This water spews up through openings in Earth’s crust.
2. When the hot water meets cold seawater, dissolved minerals precipitate (they separate out as solids) and accumulate, forming the vent’s chimney.
4. This charge may have caused chemicals to react and combine inside honeycomb-like chambers in the chimney’s walls, forming organic compounds.
3. The hot and cold waters have different chemical make-ups, creating an electric charge inside the chimney’s walls.
Paleozoic EraCambrian and Ordovician Periods - Began 543 Billion Years Ago -
--Arthropods --Sponges --Mollusks
If radiometric dating identifies the rock in layer C as 425 million years old, what can you infer about the age of the fossils in layer C? In layers B and D? Explain.
Silurian & Devonian Periods - Began 443 Million Years Ago -
In the seas, massive reefs— larger than at any other time in history—covered the ocean floor, and fishes.
Permian - Began 290 Million Years Ago -
Volcanic Activity lead to global warming.
50% of Marine Life went extinct
5th Mass Extinction
50% of all Life went extinct
The opening for an ape’s spinal column is towards the back of the skull, so the spine extends backwards and down.The opening for a hominid’s spinal column is at the bottom of the skull, so the spine extends directly down underneath the skull.
An ape’s big toe is splayed off to the side. This thumb-like toe is great for grasping, but not for weight bearing.A human’s big toe is lined up parallel with the other toes, bearing the weight of the body during the “push-off” to the next step.
An ape’s pelvis is tall and narrow.A human’s shorter and wider pelvis makes for more stable walking on two legs.
An ape’s femur (upper leg bone) extends straight down.A hominid’s femur is angled inward, positioning the knees and feet directly under the body’s center of gravity during walking.
5. Foot arches
An ape’s foot is flat.A human’s foot is arched, absorbing shock when the foot falls.
An ape’s canine teeth are relatively large.A hominid’s canine teeth are smaller by comparison.
Homo sapiens VS Neanderthals