life’s timeline
DESCRIPTION
Life’s Timeline. Earth is Born. aka The Precambrian Era. The First 100 million years. Cosmic junk hits Giant collisions melt the planet Density stratification. Hydrogen cyanide Carbon Dioxide Carbon Monoxide Nitrogen Hydrogen Sulfite Water. TOXIC!!!. The First Atmosphere. - PowerPoint PPT PresentationTRANSCRIPT
Life’s TimelineLife’s
Timeline
Earth is
Born
aka The
Precambrian
Era
The First 100 million years
• Cosmic junk hits • Giant collisions melt
the planet• Density stratification
The First AtmosphereThe First Atmosphere
– Hydrogen cyanide– Carbon Dioxide– Carbon Monoxide– Nitrogen– Hydrogen Sulfite– Water
– Hydrogen cyanide– Carbon Dioxide– Carbon Monoxide– Nitrogen– Hydrogen Sulfite– Water
• TOXIC!!!• TOXIC!!!
4 b.y.a.
• 1st solid rocks• Lots of volcanos• Cosmic junk bombards surface
• Too hot for liquid H2O!
• 1st solid rocks• Lots of volcanos• Cosmic junk bombards surface
• Too hot for liquid H2O!
3.8 b.y.a.3.8 b.y.a.
• Cool enough for liquid water• Storms cover Earth in water• Oceans form• Lots of dissolved iron in oceans
• Cool enough for liquid water• Storms cover Earth in water• Oceans form• Lots of dissolved iron in oceans
3.6 – 3.5 b.y.a.3.6 – 3.5 b.y.a.
• Bacteria-like life forms common in oceans – Evidence: microfossils!
• Bacteria-like life forms common in oceans – Evidence: microfossils!
2.2 b.y.a.2.2 b.y.a.
• Photosynthetic bacteria producing Oxygen– Oxygen + Iron in oceans = RUST
appears!– Rust falls to ocean floor = oceans turn
blue-green– Oxygen builds up in atmosphere…
• Photosynthetic bacteria producing Oxygen– Oxygen + Iron in oceans = RUST
appears!– Rust falls to ocean floor = oceans turn
blue-green– Oxygen builds up in atmosphere…
Atmospheric O2 Accumulates
Atmospheric O2 Accumulates
• Ozone forms protective layer! • Sky turns blue!• Cells DIE OR MOVE to oxygen-free
habitats (Their descendants are still there!)
• New cells use oxygen!
• Ozone forms protective layer! • Sky turns blue!• Cells DIE OR MOVE to oxygen-free
habitats (Their descendants are still there!)
• New cells use oxygen!
• Prokaryotic cells evolve interior membranes e.g. nuclei!!!
• Endosymbiosis leads to Eukaryotic cells with– Mitochondria– chloroplasts
• Prokaryotic cells evolve interior membranes e.g. nuclei!!!
• Endosymbiosis leads to Eukaryotic cells with– Mitochondria– chloroplasts
2 b.y.o2 b.y.o
• Eukaryotic cells continue to evolve Sexual Reproduction!!!– Evolution SPEEDS UP!!!, as sexual
reproduction allows allele shuffling so that offspring are not identical to their parents.
• Eukaryotic cells continue to evolve Sexual Reproduction!!!– Evolution SPEEDS UP!!!, as sexual
reproduction allows allele shuffling so that offspring are not identical to their parents.
Later…Later…
A few hundred-million years later…
A few hundred-million years later…
• Evolution of MULTICELLULAR ORGANISMS!!!
• Evolution of MULTICELLULAR ORGANISMS!!!
Earth as a ToddlerEarth as a Toddler
The Paleozoic EraThe Paleozoic Era
The Cambrian Period: 544-505 m.y.a.
The Cambrian Period: 544-505 m.y.a.
• Diversification• Firsts:
– Tough body parts (outer skeletons, shells)– Animals
•Invertebrates: jelly fish, worm, sponge•Brachiopods: (2 shells) Trilobites
• Diversification• Firsts:
– Tough body parts (outer skeletons, shells)– Animals
•Invertebrates: jelly fish, worm, sponge•Brachiopods: (2 shells) Trilobites
The Ordovician and Silurian Periods:505-410 m.y.a.
The Ordovician and Silurian Periods:505-410 m.y.a.
• Firsts:– Backbones!!! first vertebrates: jawless
fishes– Insects! (invertebrates)– Land Plants! (low to ground in damp areas)
• Firsts:– Backbones!!! first vertebrates: jawless
fishes– Insects! (invertebrates)– Land Plants! (low to ground in damp areas)
The Devonian Period:410-363 m.y.a.
The Devonian Period:410-363 m.y.a.
– Ferns and dry-land plants– SHARKS!!!
• jaws, bones, and scales
– LAND ANIMALS!•1st AMPHIBIANS!!!
– Ferns and dry-land plants– SHARKS!!!
• jaws, bones, and scales
– LAND ANIMALS!•1st AMPHIBIANS!!!
The Carboniferous and Permian Periods:363-245 m.y.a.
The Carboniferous and Permian Periods:363-245 m.y.a.
– REPTILES!!!– Huge Winged Insects!– Vast Forests! (giant ferns)
– REPTILES!!!– Huge Winged Insects!– Vast Forests! (giant ferns)
The PermianMASS EXTINCTION:
End of the Paleozoic
The PermianMASS EXTINCTION:
End of the Paleozoic
• Extinct:– 95% of ocean life– Many amphibians, land animals and
plants
• Survivors: some fish and reptiles…
• Extinct:– 95% of ocean life– Many amphibians, land animals and
plants
• Survivors: some fish and reptiles…
The Mesozoic EraThe Mesozoic Era
Age of the ReptilesAge of the Reptiles
The Triassic Period:245-208 m.y.a.
The Triassic Period:245-208 m.y.a.
• Mass Extinction of – fishes, insects, reptiles, cone-bearing
plants
• DINOSAURS!!! (225 m.y.a.)
• MAMMALS! (late Triassic)• Evolved from reptiles• Very small
• Mass Extinction of – fishes, insects, reptiles, cone-bearing
plants
• DINOSAURS!!! (225 m.y.a.)
• MAMMALS! (late Triassic)• Evolved from reptiles• Very small
The Jurassic Period:208-145 m.y.a.
The Jurassic Period:208-145 m.y.a.
• Dominant Players: Dinosaurs (on land)
• BIRDS!!!– Archaeopteryx
• Evolved from dinosaurs
• Dominant Players: Dinosaurs (on land)
• BIRDS!!!– Archaeopteryx
• Evolved from dinosaurs
The Cretaceous Period:145-65 m.y.a.
The Cretaceous Period:145-65 m.y.a.
– Land: Dinosaurs (T. rex) – Air: Birds, Flying Dinosaurs– Water: Turtles, Crocodiles, Dinosaurs,
Fish, Invertebrates
• Firsts:– Leafy Trees, FLOWERS!!! (fruits)
– Land: Dinosaurs (T. rex) – Air: Birds, Flying Dinosaurs– Water: Turtles, Crocodiles, Dinosaurs,
Fish, Invertebrates
• Firsts:– Leafy Trees, FLOWERS!!! (fruits)
The MesozoicMASS EXTINCTION
The MesozoicMASS EXTINCTION
– Over 50% of all plants and animals– All Dinosaurs
– Over 50% of all plants and animals– All Dinosaurs
The Cenozoic EraThe Cenozoic Era
The Age of MammalsThe Age of Mammals
The Tertiary Period:65-1.8 m.y.a.
The Tertiary Period:65-1.8 m.y.a.
• Warm, mild climate
– Whales, Dolphins– Grazing mammals– The earliest Human Ancestor (3.5
m.y.a.)
• Warm, mild climate
– Whales, Dolphins– Grazing mammals– The earliest Human Ancestor (3.5
m.y.a.)
The Quaternary Period:1.8 m.y.a. - Present
The Quaternary Period:1.8 m.y.a. - Present
• ICE AGES– oceans falls 100m– 20 k.y.a. – warms up – oceans rise again
• Firsts: HUMANS (~150 k.y.a.)
• ICE AGES– oceans falls 100m– 20 k.y.a. – warms up – oceans rise again
• Firsts: HUMANS (~150 k.y.a.)
Life’s Timeline
Life’s Timeline