GEN BIO LESSON 1

• Relative dating  It is the process of determining if one rock or geologic event is older or younger than another, without knowing its specific age.
• Absolute (numerical) dating - It provides more specific origin dates and time ranges, such as an age range in years.
• FOSSILS can only be found in sedimentary rocks. Fossils can’t be found on metamorphic and igneous rocks.
• geologic time scale is the “calendar” for events in Earth's history
• PRECAMBRIAN LIFE - encompasses the vast majority of Earth's history, spanning from about 4.6 billion years ago to around 541 million years ago.
• Hadean Eon - Named after the Greek god and ruler of the underworld, Hades. 
• HADEAN EON - It is unlikely that life could have formed and thrived in the extremely volatile conditions of the Hadean Eon.
• HADEAN EON - Dating back 4.6 billion years, with evidence suggesting the presence of liquid water. 
• ARCHEAN EON - Complex chemical reactions in the young oceans transformed carbon-containing molecules into simple, living cells that did not need oxygen to live. 
• ARCHEAN EON - Appearance of blue-green algae (Cyanobacteria)
• Proterozoic Eon (2.5 – 550)
• Ediacaran period - First appearance of algae and invertebrates and eukaryotic cells.
• First oxygen dependent animals formed, the Ediacara fauna.
• PHANEROZOIC EON - This is the last eon, started from 543 million years ago to present. The eon has been divided into three era: Paleozoic Era, Mesozoic Era and Cenozoic Era
• PALEOZOIC ERA (541 - 251 mya) - Paleozoic era is known as the “OLD or ANCIENT LIFE”, starting from 541 mya and lasted for 251 mya.
• Cambrian Period (542 to 490 mya) -The time when many kinds of

  invertebrates appear.
• The first fish appeared: Agnathans (jawless

  fishes), a first vertebrate
• Cambrian explosion was when most of the major animal groups started to appear in the fossil record, a time of rapid expansion of

  different forms of life on Earth.
• Ordovician Period (490 to 443 mya) - Fungi, plants, and animals colonize the Land.
• ORDOVICIAN PERIOD - First mass extinction due to the deadly temperature
• Silurian Period (443 to 416 mya) - First vascular plants (Rhyniophyta and Cooksonia) originate
• Silurian Period - First bony fishes (osteichthyans) appear.
• Devonian Period (416 to 360 mya) -Bony fishes diversified.The first insect, amphibian, and seed plant

  appeared.
• Devonian Period (416 to 360 mya) - Sudden diversification of metazoan and 2nd mass extinction due to large scale volcanic eruptions, change of temperature, lack of oxygen
• Carboniferous Period (360 to 299 mya)

  Origin of reptiles and Amphibians dominate.
• Permian Period (299 to 251 mya) -Reptiles diversify

  • Major extinction of marine organism

  About 96 percent of all marine

  species

  • Three of every four species on land

  died out. (75%)
• The Mesozoic Era began approximately 248 million years ago and lasted for 65 million years.
• Triassic Period (251 to 200 mya) - Dinosaurs evolve, origin of mammals,

  and gymnosperms (seed producing) dominate.
• Jurassic Period (200 to 145 mya)

  • Dinosaurs abundant, first birds appear,

  gymnosperms dominate.
•  Cretaceous Period (145 to 65 mya)

  Angiosperms (Flower producing) diversify

  • Dinosaurs extinct at the end of this

  period.
• Cenozoic was started from 65 mya to

  present.
• Oligocene epoch

  ▪ Origin of primates

  ▪ Purgatorius, dating back as far as 65

  million years ago (likely emerged by the Late Cretaceous and lived alongside large dinosaurs)
• Eocene epoch

  ▪ Angiosperms dominate
• Paleocene epoch

  
  

  ▪ Mammals, insects, and birds diversify
• Miocene

  
  

  ▪ Golden Age of Mammals

  ▪ Mammals and angiosperms continue

  to diversify.

  ▪ Emergence of early hominids

  ▪ Appearance of several familiar

  mammalian families such as horses,

  elephants, and whales
• Pliocene

  ▪ Bipedal human ancestor appear

  o Ardipithecus ramidus
• Pleistocene epoch

  
  

  ▪ Ice ages and origin of Homo
• Holocene epoch

  ▪ The ice age ended due to an

  increase in temperature.

  ▪ The current time we are living in.
• Pleistocene epoch

  ▪ Ice ages and origin of Homo