Looking back through time at the Earth Flashcards
(26 cards)
What can be used to date the age of the Earth?
Radiometric dating - using radiocarbon, uranium-thorium, uranium-lead etc.
What is thought about RNA and DNA?
It is thought that RNA was formed first as it is self-replicating and is much simpler. It is thought that DNA formed from RNA.
What is the Edracaran Fauna and in what time was it present?
580-524 million years ago. It included soft-bodied gelatinous organisms that rely on diffusion.
Give examples of species found in the Edracaran Fauna.
Sponges, cridana, pikaia, marella.
What is the Ordovician and what time was it present?
488-494 million years ago. Sea levels rose and marine transgressed into a shallow shelf. It was initially very hot and began to cool to present-day temperatures. 4x as many genera.
What are some examples of species found in the Ordovician?
Crinoids, brachipods, cephalopods.
What is the Silurian period and when did it occur?
444-416 million years ago. It was a warm and stable climate with warm, shallow seas. There were also storms that started occurring.
What organisms were present in the Silurian period?
Bony fish, jawed fish, sea scorpions and arthropods on land. Also simple plants.
What was the Devonian period and when did it occur?
416-359 million years ago. Warm oceans but the overall temperature was reduced as plants removed carbon dioxide from the air.
What organisms were present in the Devonian period?
Reefs, land vertebrates, fish evolved into tetrapods.
What is the Carboniferous period and when did it occur?
359-299 million years ago. A period in which a mild temperature became cooler and there were alternating phases of glaciation and melting. Vegetation covered the sea bed - did not rot and led to coal being deposited.
What organisms were present in the Carboniferous period?
First reptiles, many other animals such as giant horsetails, giant scorpions, giant amphibians and mamnmal-like reptiles.
When did the Earth’s crust form?
4.54 billion years ago.
What were the earliest prokaryotes?
Cyanobacteria.
What is the idea about the evolution of eukaryotes involving endosymbiosis?
That the eukaryotes formed from endosymbiosis of bacteria - the bacteria became the organelles of the eukaryote????
What was the Cambrian explosion?
After the Edracaran Fauna when organisms formed with skeletons, three dimensional bodies, organs, muscles and eyes.
What was the Tommotian?
Period after the Cambrian explosion where there were small, shelly fossils.
What was the Permian period and when was it?
299-251 million years ago. Pangaea - huge continental interior was very dry with massive extremes.
What type of organisms were present in the Perimian period?
Ancestors of mammals, lepidosaurs, turtles and archosaurs.
What was the Permo-Triassic Mass Extinction?
The stage inbetween the Permian and Triassic period where most of marine species became extinct, along with all of trilobites and euryptertids, radiolaria.
What was the Triassic period and when was it present?
It was 250-200 million years ago when Pangaea split from the east by Tethys. It was hot and dry with red bed sandstones and evaporites.
What types of organisms were present in the Triassic period?
Gymnosperms and ginkgophyta, modern corals, reptile groups and dinosaurs.
What was the Jurassic period and when was it?
200-145 million years ago when Pangaea broke into Laurasia and Gondwana. It had warm weak seasons.
What organisms were present in the Jurassic period?
Conifers, tgree ferns, plesiosaurs, pliosaurs, archosaurs, birds.
