Dating Methods
_________ is the death of every member of a species.
What is extinction?
Earth formed ________________ billion years ago.
What is 4.6?
The strongest evidence for finding out what species are closely related to other species
What is DNA, or genetic information
A type of rock layer that breaks through another, usually vertically
What is volcanic rock, igneous
Is a record of life forms and geologic events in Earth's history.
What is the Geologic Time Scale?
Life explodes at the beginning of this era.
What is Paleozoic?
A bat wing and a bird wing
The term for how long it takes for half of a substance to decay
What is a half life
The largest division of geologic time are ______________.
What are eons?
Vast numbers of new mammals, birds, and flowering plants appeared while others became extinct.
What is the Cenozoic era?
Sharks and dolphins both have dark upper bodies and light toned under bodies
What are analogous features
A substance has a half life of 400 years, and it is 1200 years old, this percentage of the substance has remained
What is 12.5%
There are _____ eons in Earth’s history.
What is four?
The first mammals, birds, and flowering plants appeared
What is the Mesozoic era?
Sharks and frogs both have spines
What are homologous features
A substance has a half life of ___ years, it is 2400 years old, and 6.25% of the substance remains
What is 600 years
The last of the eons
What is the phanerozoic eon
The first tetrapods, amphibians, and reptiles first appear
What is the paleozoic era
Seeing that a human embryo first develops gill like structures very early on in development is evidence of this
What is evidence that an early common ancestor of humans had gill like structures, such as a fish