Multiple Choice 1
A life form that evolved during the Paleozoic was ________.
reptiles
Humans appeared in the _______ Era.
cenozoic
Put in order: appearance of humans, dinosaurs as dominant life-forms
1. Dinosaurs as dominant life-forms
2. Appearance of humans
What effect does plate tectonics have on evolution of new species?
Changes in the environment and climate.
How does plate tectonics affect he development of new species?
The continents collide or separate, the sea drains, and mountains build.
The end of the Paleozoic Era might have involved ________.
Mass extinctions of land and sea animals.
The major subdivisions of geologic time are ______.
eons
Put in order: disappearance of Ediacaran Fauna, development of birds, evolution of cyanobacteria
1. evolution of cyanobacteria
2. disappearance of Ediacaran Fauna
3.development of birds
Why do trilobites make excellent index fossils?
Because they were widespread for a short period of time.
Why is little known about 90 percent of Earth's history?
They changed by heat and pressure. They had soft parts.
Large mammals of the Cenozoic Era may have become extinct because of activity by ________.
humans
Geologic time is divided into units based on _______.
Types of life-forms living during certain periods.
What are the two periods in the Cenozoic Era?
Quaternary and Tertiary
Describe some of the changes in the land and its life-forms that occurred at the end of the Paleozoic Era.
There was a mass extinction. Pangaea formed.
What trait has made angiosperms the dominant plant today?
The seeds are protected and enclosed in fruit.
Plate tectonics may affect changes in a species because of movement of plates causes a change in ______.
the environment, climates, Earth's surface
Changes in the exoskeleton of trilobites probably occurred because of ______.
competition for survival, changing environment, and geographic isolation
What are the epochs in the Cenozoic Era?
Holocene, Pleistocene, Pilocene, Miocene, Oligocene, Eocene, Paleocene
Why were reptiles able to evolve from amphibians?
They evolved an egg that had a shell with a water membrane inside that held moisture to the egg.
Contrast the animal life of the Mesozoic Era with that of the early Cenozoic Era.
Mesozoic: marine animals, amphibians, and reptiles
Cenozoic: mammals and birds
Trilobites can be used to study the passage of geologic time because _______.
Their physical features changed through time.
The development of ozone in the stratosphere and oxygen in the atmosphere first made possible the development of _______.
complex organisms
What species lived during the Cenozoic Era?
humans, mammals, angiosperms
Why couldn't complex organisms develop before the establishment of an ozone layer?
Harmful ultraviolet rays would shine on earth and they would not be able to survive.
What is the most significant difference between Precambrian and Paleozoic life-forms?
Precambrian had soft parts and Paleozoic had hard parts.