Earth Timeline

When did these events occur? 1. Find a length of register tape and label it “Earth’s Timeline” 2. Write 4.56 billion years ago on one end of the tape, and today on the other end. 3. As a group, place the following six events in the timeline: a.Mammals first appear b.Amphibians first appear c.Fish first appear d.Birds first appear e.Reptiles first appear f.Dinosaurs first appear

Earth’s Calendar Earth forms from planetary nebula today

HADEAN EON Of The Underworld 4.6 – 4.0 billion years ago January 1 – February 17 Planet is very HOT Surface is partially molten (melted rock) Frequent collisions with other solar system bodies January 7: Water Cycle Begins Oceans and atmosphere form

ARCHEAN EON Ancient Beginning 4.0 – 2.5 billion years ago February 18 – June 16 High volcanic activity Atmosphere thick with toxic gasses such as ammonia and methane NO OXYGEN March 28: First life on Earth! Cyanobacteria (used photosynthesis)

modern stromatolites Shark Bay, Australia fossil stromatolites Banff, Canada

PROTEROZOIC EON Early Life 2.5 billion – 542 million years ago June 17 – November 18 Earth cools off enough for continents to become stable Lots of simple life (unicellular) July 9: Oxygen builds up and kills most living things Also makes possible life for multicellular organisms and animals

eukaryotic cell prokaryotic cell

PHANEROZOIC EON Visible Life 542 million years ago – today November 18 – December 31 We are in the Phanerozoic Most life of any eon

When did these events occur? Fish arrive? Mammals arrive? Reptiles arrive? Dinosaurs arrive? Birds arrive? Amphibians arrive?

November 20: Fish first appear 530 million years ago Earliest fish may have evolved from worms Did not have jaws Later developed jaws (such as sharks) and a backbone

December 3: Amphibians first appear 370 million years ago Some fish develop lungs so they can breath oxygen from the air Able to lift themselves out of the water using bony fins (which turn into limbs)

December 7: Reptiles first appear 310 million years ago Amphibian bones become thicker and brain size increases over time Some amphibians start spending more and more time on land, growing legs, laying eggs on land Eventually become reptiles

December 14: Dinosaurs first appear 231 million years ago Some reptiles developed an erect posture (a bone structure in which they are more upright) Reptiles with this bone structure became known as dinosaurs

December 16: Mammals first appear 200 million years ago Some reptiles began to develop fur and the ability to regulate their body temperature (this is known as being warm-blooded) These animals also could produce milk and gave birth to live young (no eggs). These were known as mammals

December 20: Birds first appear 145 million years ago A small group of carnivorous dinosaurs eventually began to develop feathers. Teeth gradually disappeared and turned into beaks Bones became more hollow and arms gained flexibility to allow flight These dinosaurs became known as the first birds

When did these events occur? Fish first appear 530 million years ago November 20 Amphibians first appear 370 million years ago December 3 Reptiles first appear 310 million years ago December 7 Dinosaurs first appear 231 million years ago December 14 Mammals first appear 200 million years ago December 16 Birds first appear 145 million years ago December 20

Animal classes in the Phanerozoic Eon MASS EXTINCTION 1 MASS EXTINCTION 2 MASS EXTINCTION 3 MASS EXTINCTION 4 MASS EXTINCTION 5

MASS EXTINCTION 1 Ordovician-Silurian Mass Extinction Ma CO 2 TT 82-88% of all species died Caused by a burst of volcanic activity As rocks broke down, CO2 was taken out of the atmosphere The planet’s temperature dropped and sea levels dropped

Devonian Mass Extinction Ma MASS EXTINCTION 2 CO 2 TT 79-87% of all species died Plants and fish became widespread after the first extinction Plants had gotten much bigger Plants swallowed up a lot of the CO2 in the atmosphere Resulted in powerful roots that broke down rocks, releasing nutrients into the ocean that resulted in a lot of algae The algae released poison

Permian Mass Extinction 252 Ma MASS EXTINCTION 3 CO 2 TT 93-97% of all species died Sharks, amphibians and reptiles arrived after the second extinction The continent Pangaea formed which created hot, dry conditions on land A huge volcanic eruption happed in China and blasted tons of ash and gas into the atmosphere Lasted 600,000 years! Released CO2 into the atmopshere Caused oceans to warm which released frozen methane, creating an even hotter planet

200 Ma Triassic Mass Extinction MASS EXTINCTION 4 CO 2 TT 76-84% of all species died Life took 10 millions years to recover after the third extinction Mammal-like reptiles and dinosaurs arrived The mid-Atlantic Rift opened which increased volcanic activity, releasing CO2 into the atmosphere Mammal-like reptiles and many dinosaurs disappeared

66 Ma Cretaceous Mass Extinction MASS EXTINCTION 5 CO 2 TT Dinosaurs became dominant after the 4 th extinction Eventually more volcanic activity occurred, ejecting CO2 into the atmosphere and raising the Earth’s temp. A massive asteroid hit Earth and launched dust into the atmosphere, blocking out the sun Dinosaurs are wiped out

Patterns of Extinction in the Phanerozoic Eon CO 2 TT TT TT TT TT