EARTH & SPACE Astronomical Phenomena Origins of life Extinctions & Fossils

ASTRONOMICAL PHENOMENA A trip to the Sun, located a mere 150 million km away, at a speed of 100km/h, would take more than 170 years. This distance may seem enormous, but it is quite insignificant on the scale of the Universe. Despite a km diameter, our planet is only a tiny dot in space. 1 Astronomical Unit (Au) = 150 million km 1 Light Year (Ly) = 9500 billion km

ASTRONOMICAL PHENOMENA

ORIGINS OF LIFE About 4.6 billion years ago, our solar system was created from a cloud of gas and dust. The Sun formed at the center of that cloud, making up 98% of the solar system’s mass. The other planets and celestial bodies of the solar system formed around the sun.

ORIGINS OF LIFE The oldest fossils of living organisms dates back 3.5 million years. This means that life probably emerged between 3.5 and 3.8 million years ago. The Conditions Essential for the Emergence of Life on Earth are those conditions that made it possible for the synthesis of the first organic molecules and their development into living cells.

ORIGINS OF LIFE The Conditions Essential for the Emergence of Life on Earth are:  The presence of essential chemical elements (carbon, oxygen, hydrogen, nitrogen)  The presence of an energy source (UV rays, electricity from lightning, heat from volcanoes & hot springs)  The presence of liquid water  A very long period of time

EXTINCTIONS The EXTINCTION OF A SPECIES is the disappearance of all individuals belonging to that species. It is caused by the inability of the individuals to adapt to change(s) in their environment. Throughout history there have been 5 mass extinctions.

EXTINCTIONS 1 ST Mass Extinction: Occurred in the Ordovician period of the Paleozoic era. The climate became so cold, 50% of animal species died. 2 nd Mass Extinction: Occurred in the Devonian period of the Paleozoic era. Caused by increase in water temperature, rise in CO2 levels, and glaciation. 3 rd Mass Extinction: Occurred in the Permian period of the Paleozoic era. Caused by glaciation and volcanic activity that triggered sulphuric acid rain. This was the largest extinction, wiping out 96% of marine life and 75% of land species.

EXTINCTIONS 4 TH Mass Extinction: Occurred in the Triassic period of the Mesozoic era. Caused by meteorite impact and volcanic activity destroying 50% of fish and corals. 5 th Mass Extinction: Occurred in the Cretaceous period of the Mesozoic era. Caused by meteorite impact in Yucatan, Mexico. This was the beginning of continental drift (Pangea) and was responsible for the disappearance of the dinosaurs.

FOSSILS A fossil is any remains or trace of an organism that has been preserved for a very long period of time in Earth’s crust. Stratigraphic Layering: