History of life on Earth Flashcards
1
Q
When “eras” are grouped together, this will create the longest geologic subdivision called an “eon.”
A
Eon
2
Q
When “periods” are compacted together according to their characteristics
A
Era
3
Q
The concept of geologic time scale, basic unit of geological time during which a specific kind of rock system is produced.
A
Period
4
Q
Some “periods” have their own subdivision
A
Epoch
5
Q
Two main eons
A
- Phanerozoic eon
- Precambrian eon
6
Q
This is the most recent among the eras of the Phanerozoic Era; this era marks the age of mammals and the first human evolution.
A
Cenozoic era
7
Q
This era marks the beginning of dinosaurs, mammals, birds, and plants due to mass extinction.
A
Mesozoic era
8
Q
The explosion of diverse marine life and the largest mass extinction of marine organisms
A
Paleozoic era
9
Q
characterized by Earth’s initial formation—from the accretion of dust and gases and the frequent collisions of larger planetesimals
A
Hadean eon
10
Q
the evolution of earth’s first life forms
A
Archean eon
11
Q
modern plate tectonics became active, and the ancient cores of the continents moved over wide areas of the globe
A
Proterozoic eon
12
Q
- No continents
- Vas amount of carbon dioxide in the atmosphere
- began 3.8 billion years ago and ended 2.5 billion years ago
A
Archean eon
13
Q
- Era of old life
- plants became prevalent
- first vertebrate animals colonized the land
- divided into six periods: Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian
- started with a breakup of one supercontinent into
the continents of Gondwana and Laurasia
A
Paleozoic era
14
Q
- famed for its explosion of abundant and diverse life forms
- life had diversified into many ways of living
- some creatures had evolved hard parts such as shells
- geologist find beautiful fossils of soft and squishy creatures like Burgess Shale site
- no life on land and in little or none in freshwater
- began 545 million years ago and ended 495 million years ago
A
Cambrian period
15
Q
- few animals and plants began to explore the margin of the land but nothing colonized beyond these beachheads
- ended with a mass extinction
- began 495 million years ago and ended 443 million years ago
A
Ordovician period
16
Q
- reefs got their act together, grew really big and created a completely new type of ecosystem for marine life.
- a period of extensive seas
- bony fish made their first appearance
- On land, plants became more established
- began 443 million years ago and ended 417 million years ago
A
Silurian period
17
Q
- Age of fishes
- sea levels were high and the global climate was warm
- Growth rings from coral living
- began 417 million years ago and ended 354 million years ago
A
Devonian period
18
Q
- famed for having the highest atmospheric oxygen levels
- plants grew and died at such a great rate
- called the coal measures after its proliferation of coal- breaking rocks
- In North America, this period is divided into two epochs: Mississippian and the Pennsylvanian
A
Carboniferous period
19
Q
- started with an ice age and ended with the most devastating mass extinction the Earth has ever experienced
- all the continents of the world finally coalesced into one supercontinent
- The oxygen level plummeted too from 35% to around 15%
- began 290 million years ago, ended 248 million years ago
A
Permian period
20
Q
- Middle life
- era of dinosaurs that lasted for almost 180 million years ago
- Age of Reptiles
- divided into Triassic period, Jurassic period and
Cretaceous period
A
Mesozoic era
21
Q
- was characterized by heat, vast deserts and warm seas
- even the polar regions were warm
- very first mammals and dinosaurs evolved
- giant supercontinent Pangaea began to break apart.
- the period ended as it had begun, with an extinction event
- began 248 million years ago and ended 205 million years ago
A
TRIASSIC PERIOD
22
Q
- life was quick to recover
- became host to the most diverse range of organisms that Earth had yet seen
- First birds and some of the dinosaurs
- continental break-up during this time gave rise to the sea that would eventually widen to become the Atlantic Ocean.
A
JURASSIC PERIOD
23
Q
- with the most famous mass extinction in history
- the existing birds, mammals and plants diversifies
- Atlantic Ocean grew much wider as North and South America drew apart from Europe and Africa.
- Indian was formed at this time
- began 142 million years ago, ended 65 million years ago
A
Cretaceous period
24
Q
- era of recent life
age of the mammals
- era of recent life
- divided into three periods and seven epochs:
1. Paleogene period (Paleocene, Eocene, and Oligocene epochs)
2. Neogene period (Miocene and Pilocene epochs)
3. Quarternary period (Pleistocene and Holocene epochs)
A
Cenozoic era
25
- time of dense forests and evolutionary experiments
- island continent of India moved north and collided with Asia
- At the end of the epoch, an abrupt rise in temperature across the planet made the climate much wetter and caused a sea level rise.
- began 65 million years ago and ended 54.8 million years ago
Palaeocene epoch
26
- began as a time of global warming, with temperatures across the planet soaring.
- became cooler and drier
- As the India continued to drift northwards, pushing against the Eurasian continent, the mass of rocks thrust up between them formed the Himalayas
- many species of grass evolved
- began 54.8 million years ago and ended 33.7 million years ago
Eocene epoch
27
- saw the start of the global cooling
- Worldwide, this was the time when grasslands began to expand and forests-especially tropical ones-shrank correspondingly
- Open landscape and many fast-running prey and
predator species arose as a result.
Oligocene epoch
28
- apes arose and diversified
- by the end of this epoch, the ancestors of humans had split away from the ancestors of the chimpanzees to follow their evolutionary path
- kelp forests made their first appearance
- grasslands continued to expand and forests dwindle in extent
- began 23.8 million years ago and ended 5.3 million years ago
Miocene epoch
29
- very similar to Earth today as North and South America had been drifting
- As the world cooled in the late Pilocene, ice at the North Pole became thrived
- human lineage split away from the chimpanzees’ early on in this epoch
- began 5.3 million years ago and ended 2.6 million years ago
Pliocene epoch
30
- expansion of the deserts and the action of glaciers grinding up rocks meant that dust storms.
- began 2.6 million years ago and ended 11.7 thousand years ago
Pleistocene epoch
31
- current geological epoch which started 11,500 years ago
- Ongoing phase of Earth’s history
- period that humans evolved
Holocene epoch
