Biology 2 │ Geological Time Scale

• A record of the life forms

  and geological events in

  Earth’s history

  Geologic Time Scale
• physical subdivision of the rocks

  found in the Earth's geology and the time and order of events they represent

  Relative Time
• the measurement taken from the

  same rocks to determine the amount of time that has expired

  Absolute Time
• Absolute Dating is exemplified by when you give your age
• relative dating is exemplified when you look at two adults and recognize that one is older than another but you do not know when they were born
• last for billions of years

  Eons
• last for hundreds of millions of years

  Eras
• last for tens of millions of years

  Periods
• last for less than ten million years

  Epochs
• Pre Cambrian Period is also known as?

  Supereon
• Pre Cambrian is composed of?

  Hadean, Archean, Proterozoic Eon
• Precambrian Life covers approximately _% of the earth’s

  history

  88
• Started with the planet’s creation about 4.5

  billion years ago from dust and gas orbiting the sun and later transformed to liquid rock enveloped with hot, non-breathable gases mostly composed of carbon dioxide, nitrogen, and sulfur


  Precambrian Life
• during Precambrian Life, single-celled ________ existed

  cyanobacteria
• sponge which life era started to exist?

  Precambrian Life
• Precambrian Life (Proterozoic Eon)

  • Greatly affected by the movement of the tectonic plates forming the supercontinent?

  Rodinia
• Precambrian (Proterozoic Eon)

  Earth’s core and atmosphere cooled down and brought about

  Ice Ages
• Oxygen production by the primitive

  cyanobacteria caused a drastic change in the chemical composition of the earth’s atmosphere.

  True
• • Many species of bacteria and protists were

  killed by higher concentrations of oxygen,

  while new types of organisms evolved.

  True
• During Proterozoic Eon, _______ ______ , the first multicellular

  organisms, dominated

  aerobic eukaryotes
• Phanerozoic Eon, consists of 3 eras:

  1. Paleozoic
  2. Mesozoic
  3. Cenozoic
• Paleozoic Era consists of 7 periods:

  1. Cambrian
  2. Ordovician
  3. Silurian
  4. Devonian
  5. Mississipian
  6. Pennsylvanian
  7. Permian
• Cenozoic Era consists of 3 periods:

  1. Paleogene
  2. Neogene
  3. Quaternary
• Paleogene Epoch:

  1. Paleocene
  2. Eocene
  3. Oligocene
• Neogene Epoch:

  1. Miocene
  2. Pliocene
• Quaternary Epoch:

  1. Pleistocene
  2. Holocene
• Paleozoic Era

  • Known as “Old Life”

  • Started more than 540 millions of

  years ago and lasted for more than

  300 million years
• This era began with the breakup of

  supercontinent Rodinia into the

  continents Gondwana and Laurentia?

  Paleozoic Era
• Climate warmed near the end of the

  first half of the Paleozoic?


  True
• During the latter half of Paleozoic Era, landmasses

  began moving together, forming a

  single supercontinent called Pangaea.
• Paleozoic Era (Cambrian Period), which occurred

  ~542-488 million years ago, ushered

  the most massive occurrence of

  evolution and divergence of the

  species.
• It is believed that most of the animal

  phyla in existence today had their

  origins during this time, often referred

  to as the Cambrian explosion
• Trilobite is one of the most

  dominant species during

  the Cambrian period; an

  arthropod that was among

  the first animals to exhibit a

  sense of vision
• The cause of the Cambrian

  explosion is still debated upon theories, like the rising atmospheric oxygen levels and

  large increases in oceanic calcium

  concentrations that preceded the

  Cambrian period may have

  created a suitable environment for

  animal life

  TRUE
• Paleozoic Era (Ordovician Period)

  • Plant life first appeared on land.

  • This change allowed formerly

  aquatic animals species to invade

  land, feeding directly on plants
• Paleozoic Era (Ordovician

  Period)

  • Bryophytes– mosses; most

  likely closely related to the

  first plants that colonized land
• TRUE OR FALSE

  Paleozoic Era

  •Throughout the remainder of the

  Paleozoic era, continual changes in

  temperature and moisture due to

  continental plate movements

  TRUE
• Paleozoic Era encouraged the development of new adaptations to terrestrial

  existence in animals, such as

  limbed appendages in amphibians

  and epidermal scales in reptiles
• largest mass extinction in

  history also occurred, wiping out

  approximately 90% of all marine

  animal species and 70% of land

  animals?

  Permian Period
• •Possible causes of mass extinction for Permian Period

  1. Lower sea levels when the

  continents were rejoined as

  Pangaea

  2. increased volcanic activity

  3. climate changes