Qtr. 1 Lesson 4: Emergence Of Humankind Flashcards
What is the Prehistoric Period?
The Prehistoric Period refers to the period in Earth’s history before the existence of humans.
The early history of Earth is measured in _______.
geologic time
A major division of geologic time is the _______ which encompasses several million years.
eon
The earliest eons were the _____, _____, and ______. These three geologic time periods cover the length of time from the Earth’s formation 4.5 billion years ago until about 600 million years ago.
Hadean, Archaean, & Protozeroic eons
The fourth and current geologic eon is the _______, which began approximately 541 million years ago (Mya) with what experts consider an “explosion of life” on the planet.
Phanerozoic Eon
The _______ resulted in the most intense and widespread burst of life on the planet.
Cambrian Explosion
The period from the first emergence of life forms to the emergence of the dinosaurs as the dominant life on the planet was called the _______.
Paleozoic Era (541 to 251 mya)
Cambrian (541 to 485 mya) to the Ordovician (485 to 443 mya) Periods, all the life on the planet were confined within the oceans.
True
The earliest life forms consisted of ancient worms and tiny, jawless fishes. These were the first ______ - animals with simple spinal cords which were the ancestors of vertebrates or creatures with a backbone.
chordates
The ________ are creatures with jointed exoskeletons. The most well-known of these were the trilobites-creatures with flat, segmented, plated bodies.
arthopods
During the Silurian Period (443 to 419 mya), primitive insects such as centipedes and arachnids also began to appear.
True
During the Devonian Period (419 to 358 mya) the fishes underwent their greatest development, and oceans were filled with a diverse array of marine life.
True
During the Devonian Period, several species of bony Jawed fish appeared. Prehistoric sharks also emerged, as well as the bony, scaled fish that became the ancestors of modern day fish.
True
During the Carboniferous Period (358 to 299 mya), a vast lowland swamp forests covered the land. These lush forests further decreased the carbon dioxide in the atmosphere and enriched it with oxygen. The oxygen rich environment resulted in the emergence of gigantic creatures.
True
During the Carboniferous Period, _______ were the dominant land species.
amphibians
When the Permian Period occured (299 to 252 mya), reptiles became the most dominant species on land.
True
It was in this geologic period that the earliest ancestors, called the therapsids-reptiles, of the mammals emerged.
Permian Period (299 to 252 mya)
The _______ at the end of the Permian Period gave way to a new era in geologic time.
“Great dying”
This era is often called the Age of Reptiles, as several reptile species became the dominant life forms on the planet.
Mesozoic Era (252 to 66 mya)
The Mesozoic Era was divided into three periods: _____, _____, and _____.
Triassic, Jurassic, & Cretaceous
During the middle of Triassic Period, the supercontinent of Pangaea began to separate, forming the landmasses of _____ and _____.
Laurasia & Gondwanaland
During this period, the dinosaurs became the dominant land animals on the planet.
Jurassic Period (201 to 145 mya)
During the Jurassic Period, many of the land-dwelling dinosaurs fall into three main groups: _____, _____, & _____.
Herbivorous sauropods; carnivorous theropods; and winged pterosaurs
During the Cretaceous Period (145 to 66 mya), new species of dinosaurs emerged, such as the Iguanodon, Triceratops, and Tyrannosaurus rex.
True
