HISTORY OF LIFE ON EARTH Flashcards
How old is the Earth?
- 6 BILLION YEARS OLD
3. 5 BILLION YEARS AGO (LIFE STARTED TO AROSE ON EARTH)
What processes have produced innermost changes shown by geologic pieces of evidence such as fossils?
- GRADUAL PROCESSES
2. CATASTROPHIC PROCESSES
What do you call to the geologic pieces or the remains of organisms and evidence of life on earth?
FOSSILS
WHY DO WE NEED TO STUDY THE GTS (GEOLOGIC TIME SCALE)
It reminded us of our time and place in the universe
It is a calendar of events of Earth’s history of life where they are arranged in chronological order.
GEOLOGIC TIME SCALE
Where does ancient life forms discovered?
Through layers of rocks life sedimentary rocks or through fossilized/ petrified remains
WHAT ARE THE MAJOR PARTS OF GEOLOGIC TIME SCALE?
EON -> ERA -> PERIOD -> EPOCH
WHAT ARE THE THREE EONS IN THE GEOLOGIC TIME SCALE?
- Phanerozoic eon
- Proterozoic eon
- Archaean eon
It happened 542 million years ago where single-celled organisms came into existence.
The end of this span is the rise of few more complex animals in the oceans such as Jellyfish
There was still no life on land, and the atmosphere was just beginning to accumulate the oxygen requirement for higher-order animals to survive.
Precambrian era
It is an era that began with the Cambrian Explosion a relatively rapid period of speciation kicked off a long period of life flourishing on Earth.
There are a huge number and kinds of living organisms from the ocean that moved towards the land.
It is believed that plants were the first to migrate towards land, followed by invertebrates and many other species also appeared and thrived on land.
The end of this Era comes with the largest mass extinction in the history of life on Earth, wiping out 75 percent of marine life and nearly 70 percent of life on land.
Paleozoic era
It is an era which was also known as the “age of dinosaurs” since dinosaurs were the dominant species of this age.
The climate during this Era was very humid and tropical, which many lush, green plants sprouted all over the Earth.
Herbivores thrive and small mammals came into existence, birds developed evolved from the dinosaurs.
MESOZOIC ERA
This era began 65 billion years ago to the present, this final era on the GTS wherein smaller mammals survived and become dominant.
The climate of this Era is cooler and drier compared to the Mesozoic Era.
This is an “Ice Age” which covered most temperate regions of the Earth with glaciers.
All species of life- including humans evolved into their present-day form throughout this era.
CENEZOIC ERA
