Changes in Nature 18th October
- What are Geologic Time Periods?
The geological time is a system of chronological measurement, that relates to stratigraphy time. It is used by geologists, paleontologists, and also other Earth scientists to describe the timing and relationships between events that have occurred throughout Earth’s history.
- Name them
- Why are they important to scientists?
Time is a very important in geology, this is because the exact timing of spatially separated events allows us to reconstruct the surface and surface conditions of the ancient earth. Scientist are discovering more about time and also geology that's why this is important.
Geologic Time Periods 19th October
Period + What happened
Earth forms 4.6 Billion years ago.
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Precambrian Earliest
- 1st organisms single called, oxygen present
- Later, multi celled organisms
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Cambrian 540 million years ago (Paleozoic)
- Lots of different organisms
- Earliest animals with backbone
- Lots of carbon dioxide
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Ordovician 490 million years ago (Paleozoic)
- Lots of animals without skeletons
- Early shellfish, trilobites, nautilus, starfish + fish
- 1st green plants and fungi
- End of Ice age
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Silurian 443 million years ago (Paleozoic)
- 1st advanced plants
- Jawed fish with armour
- more shellfish
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Devonian 416 million years ago (Paleozoic)
- 1st ferns
- 1st fir trees with seeds
- 1st wingless insects
- 1st amphibians
- Some animals from earlier periods die out.
- Most climate cool
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Carboniferous 354 million years ago (Paleozoic)
- Swampy land
- 1st "coal" forest (trees --> coal over millions of years)
- Early sharks, large trees
- 1st reptiles and vertebrates
- Trilobites disappearing
- Glaciers form
- Winged insects
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Permian 290 million years ago (Paleozoic)
- Land masses have formed 1 continent "Pangaea"
- Glaciers disappear (warming up)
- Lots of reptiles
- 1st cone bearing trees
- Beetles and flies appear
- Lots of life in oceans
- 251 Million years ago = 95% life --> extinct
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Triassic 248 million years ago (Mesozoic)
- Dinosaurs appear
- First mammals and crocodiles appear
- Modern corals and fish
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Jurassic 206 million years ago (Mesozoic)
- Lots of different dinosaurs
- Ferns and cone bearing plants
- Mammals common but small
- First birds and lizards
- Land mass, Pangaea breaks up into Gondwanaland and Laurasia
- High carbon dioxide levels
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Cretaceous 144 million years ago (Mesozoic)
- Lots of dinosaurs including Tyrannosaurs
- New types of insect
- Flowering plants appear and become plentiful
- Modern Crocodiles and sharks
- Early birds appear
- Gondwanaland breaks up
- Rocky mountains appear
- Carbon dioxide similar to today
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Paleogene 65-23 million years ago (Cenozoic)
- Modern Plants
- Lots of different mammals
- Dinosaurs extinct
- Primitive whales
- First Grasses
- Rapid changes in mammals
- Climate cools
- Ice age begins and ends during this period
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Neogene 23-5.3 million years ago
- Modern climate
- Modern mammals and birds
- Horses evolve from dog like animal
- Lots of grasses
- First Apes
- Southern Alps of NZ appear
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Quaternary 1.8 million years ago (Present)
- Anatomically moderns humans
- Human stone age culture
- Ice age comes and goes
- Sahara forms from grassland
- Humans begin algriculture
- Stone age --> Bronze age 3300 BC --> Iron age 1120 BC
- Industrial revolution leads to rise in carbon dioxide levels
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- Dinosaurs appear
- First mammals and crocodiles appear
- Modern corals and fish
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Jurassic 206 million years ago (Mesozoic)
- Lots of different dinosaurs
- Ferns and cone bearing plants
- Mammals common but small
- First birds and lizards
- Land mass, Pangaea breaks up into Gondwanaland and Laurasia
- High carbon dioxide levels
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Cretaceous 144 million years ago (Mesozoic)
- Lots of dinosaurs including Tyrannosaurs
- New types of insect
- Flowering plants appear and become plentiful
- Modern Crocodiles and sharks
- Early birds appear
- Gondwanaland breaks up
- Rocky mountains appear
- Carbon dioxide similar to today
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Paleogene 65-23 million years ago (Cenozoic)
- Modern Plants
- Lots of different mammals
- Dinosaurs extinct
- Primitive whales
- First Grasses
- Rapid changes in mammals
- Climate cools
- Ice age begins and ends during this period
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Neogene 23-5.3 million years ago
- Modern climate
- Modern mammals and birds
- Horses evolve from dog like animal
- Lots of grasses
- First Apes
- Southern Alps of NZ appear
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Quaternary 1.8 million years ago (Present)
- Anatomically moderns humans
- Human stone age culture
- Ice age comes and goes
- Sahara forms from grassland
- Humans begin algriculture
- Stone age --> Bronze age 3300 BC --> Iron age 1120 BC
- Industrial revolution leads to rise in carbon dioxide levels
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