History of Life Flashcards
Smallest division of the
geological time scale
Epoch
a division of geologic
history with spans of no
more than 100 million
Period
Division that span time
periods of tens to hundred
of million of year
Era
Largest division of the
geological time scale; half
billion - 2 billion of years
Eon
remnant, impression, or trace of
an animal or plant past a geological age
that has been preserved in the Earth’s
crust
Fossils
The complex of data recorded in fossils
worldwide is known as ______ which is
the primary source of information about the
history of life on Earth.
Fossil record
lasted for 4.5 million years; about 88 % of the Earth’s history
Precambrian Eon
The solidification of the earth’s continental and oceanic crust
Hadean Eon (4.6 Billion Years ago)
The evolution of earth’s first life forms
Archean Eon ( 4 Billion Years ago)
The appearance of multi-celled animals and the
gathering of land masses to form continents
Proterozoic Eon (2.5 Billion Years ago)
Known as the oldest fossil
Stromatolite
The era that began with a spectacular burst of life.
cambrian period ( 544-505 MYA)
_____ - prehistoric sponges
_____ - Trilobites
Echinoderms and Arthropods
The ocean were filled with many invertebrates
The first fish evolved
Plants colonized the land for the first time, but
animals still remained in water
ordovician period
(505 - 440 Million years ago)
In the ocean, corals appeared and fish
continued to evolve
On land, vascular plants appeared. With special
tissues to circulate water and other materials.
Silurian Period ( 440-410 Million years ago)
The first seed plant evolved. Seeds have
protective coat and food to help them survive.
Fish with lobe fins evolved. They can breath air
when they raised their heads above water.
devonian period
(410 - 360 Million years ago)
Wide spreading of forest left deposits of carbon that turned into coal
The first amphibians & reptiles colonized land
CARBONIFEROUS period
(360 - 290 Million years ago)
All major land masses collided to form Pangea
Temperature were extreme and climate was dry
Plants evolved with waxy leaves, while animals evolved with leathery skin to avoid water loss.
PERMIAN period (290 - 245 Million years ago)
Age of Reptiles
“ Era of Dinosaurs”
MESOZOIC ERA
(280 Million years ago)
First Dinosaur colonized the land, air, and water
Huge seeds, ferns and conifers dominated the forests, and modern corals, fish, and insects.
The Pangea started to separate into Laurasia & Gondwanaland
Ended with another mass extinction.
TRIASSIC PERIOD
(251 Million years ago)
“Golden Age of Dinosaurs”
Earliest bird and mammal evolved
First flowering plants and new insects (pollinator)
Continents continued to move (Volcanic Activity)
JURASSIC PERIOD
(203.1 Million years ago)
Dinosaurs’ peak in size and distribution
Earth’s climate was warm; the poles lacked ice
Continents were close to their present locations
Ended with extinction of the dinosaurs
CRETACEOUS PERIOD
(145 Million years ago)
Age of Mammals
“ Recent Life”
CENOZOIC ERA (65 Million years ago - present)
Climate was generally warm and humid
Mammals evolved (Increase in size)
Primates evolved (human ancestors)
Modern rainforest and grassland appeared
Flowering plants and insects are numerous
TERTIARY PERIOD/ PALEOGENE & NEOGENE PERIOD
(65 - 1.8 Million years ago)
First rodents, rabbits, primates and carnivores.
Small mammal became larger
Paleocene epoch
(65.5 – 55.8 Million years ago)
Hyracotherium, echinoids abundant
Whale-like mammal, hyena-like mammal
eocene epoch
(56 Million years ago)
Hominoids (Early Apes)
Mesohippus, basic orders of mammals present
oligocene epoch
(33.9 Million years ago)
Major Climatic Changes
Pigs, Camels, Cattles, Deer, Giraffe, Merychippus
Miocene epoch
(23 Million years ago)
Pliohippus, H. Habilis (2.5MYA), H. Erectus (1.8 MY)
Hominids (earliest humans 4.4 MYA), Australopithecus
Pliocene epoch
(5.3 Million years ago)
Climate cooled leading to a series of ice age
Sea levels fell because water froze into glaciers
Created land bridges between continents, allowing land animals to move to new areas
quaternary PERIOD
(1.8 Million years ago - present)
Equus (Horse), Cro-Magnon
Ice-age begins, Neandertals
Extinction caused by over predation and lack of vegetation
Pleistocene epoch
(2.6 Million years ago)
Sumerian Civilizations (0.006 MYA)
Ice Age ends
Agriculture and Development
holocene epoch
(0.01 Million years ago)
Known as the first avian (bird)
Archaeopteryx (its descendant is turkey)
It’s known as the early marsupial
Pseudotribos
First flowering plant
Nanjinganthus
methods estimate whether an object is younger or older than other things found at the site. Does not offer specific dates, it simply allows to determine if one artifact, fossil, or stratigraphic layer is older than another.
Relative dating
methods provide more specific origin dates and time ranges, such as an age range in years. How specific these dates can be will depend on what method is used.
Absolute dating
molten rocks, no lifeforms
- named after hades (greek god of the underworld)
Hadean
rise of cyanobacteria
-stromatolites (cyanobacteria fossil)
Archaen eon
formation of stable continents, the appearance of abundant bacteria and archaea, and the buildup of oxygen in the atmosphere.
Proterozoic Eon
Paleo means __?
Ancient or old
Many organism in this era are invertebrates
Paleozoic Era
During cambrian period there is an abundance of ___ and ___
Oxygen and Calcium
