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Why did geologists develop the geologic time scale?
The geological time scale is the geologic history of the planet from formation to the present. It starts with large divisions of time called eons and is subdivided into successively smaller units of time based on dominant lifeforms, extinction events, even climate. The development of the geologic time scale was initially based on the observation and reasoning that deeper layers of rock are generally older than less deep layers in what is called the "Law of Superposition".Paleontologists look for index fossils in fossil bearing sedimentary rock. Index fossils are organisms that were widespread, rapidly evolving, and only existed for a short period of time as evidenced by their appearance in the fossil record of specific rock strata. The appearance of a fossil alongside an index fossil gives a rough approximation of the age of the fossil in relative terms as it would appear on the geologic time scale. The appearance of the same fossil alongside index fossils of different geologic ages means that the fossil organism spanned multiple geologic time periods. Associations of specific strata alongside radiographically datable igneous and metamorphic rock determines the absolute age of a fossil.A period of around 4,600,000,000 years, the largest groupings of geologic time are eons, followed in descending order by era, period, epoch, and age.The geologic time scale is very important, especially in fields involving the exploration and retrieval of fossil fuels, which are geologically date range specific.
What makes a species a good index fossil?
An index fossil is used as an indicator of which era/epoch was preserved. The major characteristic necessary to be an index fossil include abundance, widely distributed, but lived for a short period of time.
When did modern humans appear on earth according to fossil records?
According to the fossil records, the modern humans did appear on earth more than 130,000 years ago.
What fossil evidence is considered an intermediate between reptiles and birds?
The oldest bird fossil Archaeopteryx is a transitional form between reptiles and birds and is cited as evidence Describe three additional pieces of evidence for this claim?
What is the definition of range of a fossil species?
The range of a fossil species refers to the span of time during which the species existed on Earth. It is determined by the oldest and youngest known occurrences of that species in the fossil record. The range provides information about the species' period of existence and can be used to study evolution and environmental changes over time.
Abundant fossil evidence did not appear in the geologic record until what geologic era?
Abundant and diverse fossils first appeared in the Cambrian era, although there is fossil evidence throughout much of the Precambrian.
Abundant fossil evidence did not appear in the geologic record until about?
The abundant fossil evidence appeared in the geologic record around 541 million years ago during the Cambrian period when complex organisms started to evolve. This sudden appearance of diverse life forms is known as the Cambrian explosion.
When did abundant fossil evidence appearing the geologic record?
540 Million years ago
When did abundant fossil evidence appear in the geologic record?
Abundant fossil evidence first appeared in the geologic record during the Cambrian Period, around 541 million years ago. This period marked the rapid diversification of multicellular organisms, leading to the Cambrian Explosion, which left behind a rich fossil record of early marine life.
What percent of geologic time is represented by abundant fossil evidence?
The planet Earth is about 4,600 million years old. Fossil evidence becomes abundant in the geological record in the Cambrian Era, which was about 550 million years ago (when hard shelled animals appeared) Therefore (550/4600)*100 = roughly 12% of Geological time contains abundant fossil evidence. However, please note that (non abundant) fossil evidence goes back about 3600 million years, (3600/4600)*100 = roughly 73% of Geologic time.
What evidence do scientist use to place events on the geologic time scale?
they use major fossil records
4. What are the three traits of an index fossil?
There are technically more than three traits and those traits are distinctive, widespread, abundant and limited in geologic time.
When did the first cyanobacteria appear?
Fossil evidence of Cyanobacteria indicates an age of up to 2.8 billion years.
What is the Geologic time with the poorest fossil record?
Precambrian
What does the geologic scale measure?
It measures the age of a fossil.:)
How paleontologists use trilobite fossil as index fossil for various geologic time period?
yeah
geologic time with poorest fossil record?
Precambrian time.
