Week 4- History of Life on Earth II - Mesozoic and Cenozoic Era Flashcards
Life in Geologic Eras
Precambrian Era
Paleozoic Era
Mesozoic Era
Cenozoic Era
Known as ‘Middle Life’, started more than 252 mil. yrs. ago and lasted until 66 mil. yrs. ago.
Mesozoic
Has 3 geologic periods: Triassic, Jurassic, and Cretaceous.
Considered as the Age of Dinosaurs and Age of Conifers.
Mesozoic
In this period, which lasted from 252 mil. yrs. ago until 201 mil. yrs. ago, its terrestrial environment was dominated by the therapsids, sometimes referred to as “mammal-like reptiles,” and the thecodonts, ancestors of dinosaurs and
crocodiles, both of which appeared during the Late period of this time, together with lizards, turtles, flying pterosaurs, and the first true
mammals.
Triassic Period
In the oceans, mollusks, including ammonites, belemnites, and gastropods, became a dominant group. Fishes, sharks, and marine reptiles such as plesiosaurs, nothosaurs, and ichthyosaurs also swam the Mesozoic seas
Triassic Period
In this period, which lasted from 206 mil. yrs. ago until 144 mil. yrs. ago,
Jurassic Period
The__________ terrestrial
environment was dominated by Sauropods, which is characterized by their long necks and tails, and Theropods, which are bipedal
carnivorous dinosaurs.
Jurassic
Feathered dinosaur first appeared and the first true coral was formed.
Jurassic Period
For plant life, cycads has
dominated the continents
Jurassic Period
In this period, which lasted from 144 mil. yrs. ago until 65 mil. yrs. ago,
Cretaceous Period
was dominated by the dinosaurs
still, particularly by duck-billed Hadrosaurs and horned ceratopsians.
Cretaceous Period
-New species have appeared
like the infamous Tyrannosaurus rex.
-This is also the time when flowering trees has emerged and also the placental mammals.
Cretaceous Period
Known as ‘Recent Life’, started more than 66 mil. yrs.
ago and is continuing today.
Has 2 geologic periods
Considered as the Age of Birds and Mammals.
Cenozoic
2 geologic periods of Cenozoic
Paleogene and Neogene
5 Mass Extinction
Ordovician-Silurian Extinction: 440 million years ago.
Devonian Extinction: 365 million years ago.
Permian-Triassic Extinction: 250 million years ago.
Triassic-Jurassic Extinction: 210 million years ago.
Cretaceous-tertiary Extinction: 65 Million Years Ago.
a mass extinction event took place 200 million years ago, eliminating about
80% of Earth’s species, including many
types of dinosaurs.
The Triassic Mass Extinction
This was probably caused by colossal
geological activity that increased carbon
dioxide levels and global temperatures, as
well as ocean acidification.
The Triassic Mass Extinction
a mass extinction event occurred 65 million years ago, killing 78% of all species, including the remaining non-
avian dinosaurs.
The Cretaceous Mass Extinction
This was most likely caused by an asteroid
hitting the Earth in what is now Mexico,
potentially compounded by ongoing flood
volcanism in what is now India.
The Cretaceous Mass Extinction
Organisms found in Triassic Period
Land:
Therapsids and thecodonts
Lizards
Turtles
Flying pterosaurs
First True Mammals
Water:
Mollusks
Fishes
sharks
Marine reptiles (plesiosaurs, nothosaurs, and ichthyosaurs)
Organisms found in Jurassic Period
Sauropods
Therapods
plant: Cycads
Organisms found in Cretaceous Period
Dinosaurs:
duck-billed Hadrosaurs
horned ceratopsians
Tyrannosaurus rex.
Plants: flowering trees
The condylarths-ancestors of modern hoofed herbivores
Rodents - multituberculates
The first Primates
Opossum-like Marsupials
First Hares/Rabbits
Creodonts – catlike and doglike animals
Paleocene (66-56 mya)
Ancestral Bats
Ancestral Elephant
Cetaceans and Sirenians
Eohippus-the first horse
Perissodactyls – odd-toed ungulates
Artiodactyls – even-toed ungulates
Eocene (55-34 mya)
Mesohippus and Miohippus
Mastodons (Mammoth Ancestor)
Parapithecus (New World Monkeys)
Indricotherium (largest mammal)
Primitive Beavers
Oligocene (33-23 mya)
Multiple forms of Horses
First Dogs and Bears
First Hyenas
First Saber-tooth Cats
Dryopithecines – humanlike apes
Modern whales
Ancestral seals and walruses
Miocene (23-5.3 mya)
First hominids-australopithecines
Ground sloths
Glyptodonts
Beginning of Ice age – temperature begins to cooldown
Pliocene (5.3-2.5 mya)
Wooly Mammoths, Wooly Rhinoceros and Saber-tooth Tiger in temperate climates
Elephants, Mastodons, Bison, hippopotamus, Hogs, Deer, Horses in tropical climates
H. habilis, H. erectus and other Homo species
Great Ice Age
Pleistocene (2.5 mya-12 kya)
Human History
Holocene (12 kya - Present)
Periods in Quaternary
Pleistocene (2.5 mya-12 kya)
Holocene (12 kya - Present)