remnants, impression, or trace of an animal or plant of a past geologic age that has been preserved in Earth’s crust.
Fossil Record - primary source of information about the history of life on Earth.
Geologic Time Scale
a record of life forms and geologic events in Earth’s history. Divided into Eon, Era, Period, and Epoch.
Eon
the largest division of geologic time scale; half billion - nearly 2 billion years.
88% happened during the PRECAMBRIAN represented by HADEAN, ARCHEAN, AND PROTEROZOIC EONS.
Eons
Hadean
Archean
Proterozoic
Phanerozoic - current geological eon that began approximately 541.0 million years ago.
Era
Division that spans time periods of tens to hundreds of millions of years.
Phanerozoic eon eras:
Paleozoic
Mesozoic
Cenozoic
Periods
division in geologic history with spans of no more than 100 million years.
The Paleozoic Era
meaning ”ancient or old life”. It started more than 540 million years ago. Many organisms that have emerged during this time were invertebrates.
Periods of Paleozoic Era:
Cambrian
Ordovician
Silurian
Devonian
Carboniferous
Permian
CambrianPeriod
following the Precambrian mass extinction, there was an explosion of new kinds of organisms.
sponges evolved and small ocean invertebrates called trilobites were very abundant.
Ordovician Period
oceans were filled with invertebrates of many types.
The first fish evolved. Plants colonized the land for the first time, but animals still remained in the water.
Silurian Period
in the oceans, corals appeared and fish continued to evolve.
Vascular plants appeared. With special tissues to circulate water and other materials.
Devonian Period
The first seed plants evolved. Seeds have a protective coat and stored food to help them survive.
Fish with lobes, and fins evolved. They could breathe air when they raised their heads above water
Carboniferous Period
widespread forest of huge plants left massive deposits of carbon that turned into coal.
The first amphibians evolved to colonized land, but they need to return to water to reproduce.
the first reptiles evolved. They were the first animals that could reproduce on dry land.
Permian Period
major land collided to form a supercontinent called Pangaea.
Temperature was extreme, and the climate was dry.
Mesozoic Era
Also known as the “Age of Reptiles” that started more than 280 million years ago.
Periods of Mesozoic Era
Triassic Period
Jurassic Period
Cretaceous Period
Triassic Period
The first dinosaurs branched off from the reptiles and colonized the land, air, and water.
Huge seed ferns and conifers dominated the forest.
The supercontinent Pangea also started to separate into Laurasia and Gondwanaland.
Jurassic Period
“The Golden Age of Dinosaurs”, earliest birds evolved from reptile ancestors.
Flowering plants also appeared for the first time and new insects also evolved to pollinate the flowers.
Cretaceous Period
dinosaurs reached their peak in size and distribution.
the continents were close to their present locations.
Cenozoic Era
“Age of Mammals”, translates to “ recent life”, started 65 million years ago and continues up to the present.
Periods of Cenozoic era
Tertiary Period
Quarternary Period
Tertiary Period
Earth’s climate was generally warm and humid.
MAMMALS - primate EVOLVED INCLUDING HUMAN ANCESTORS
modern rainforest and grassland appeared
flowering plants and insects were widespread
Quarternary Period
EARTH'S CLIMATE COOLED leading to a series of ice age
created land and bridges between continents allowing land animals to move to new areas
mammals like WOOLY AND MAMMOTHS, adapted to COLD by having thick fur and very large size
Epochs
Smallest division of the geologic time scale.
Epochs of the Quarternary Period
Pleistocene Epoch - hominid line continues to evolve during this period
Holocene Epoch - "Age of Man." the climate has seen some warming and cooling and large mammals have gone extinct. Humans have possibly caused the holocene extinction.