"determining the age of an object or event in years, usually by measuring the amount of unstable atoms in the sample"
describes an organism that does not need oxygen
an early hominid that evolved more than 3.6 million years ago
"the period in the geologic time scale beginning about 65 million years ago and continuing until the present day"
a cell that contains a central nucleus and a complicated internal structure
describes a species of organism that has died out completely
the solidified remains or imprints of a once-living organism
Geologic time scale
the division of Earth's history into distinct intervals of time
"for a particular radioactive sample, the time it takes for one-half of the sample to decay"
"the family referring specifically to humans and several extinct, humanlike species, some of which were human ancestors"
a period when a large number of species die out at the same time
"the period in the geologic time scale beginning about 248 million years ago and ending about 65 million years ago"
"a species of hominid that lived in Europe and western Asia from 230,000 years ago to about 30,000 years ago"
"a gas molecule that is made up of three oxygen atoms; absorbs ultraviolet radiation from the sun"
"the period in the geologic time scale beginning about 570 million years ago and ending about 248 million years ago"
"the single landmass that contained all the present-day continents 200 million years ago"
the process by which plants capture light energy from the sun and convert it into sugar
"the study of the forces that drive the movement of pieces of Earth's crust around the surface of the planet"
"the period in the geologic time scale beginning when Earth originated, 4.6 billion years ago, and ending when complex organisms appeared, about 540 million years ago"
"a type of mammal that includes humans, apes, and monkeys; typically distinguished by opposable thumbs and binocular vision"
a cell that does not have a nucleus or any other membrane-covered organelles; also called a bacterium
"the first primate ancestors; also a group of living primates that includes lorises and lemurs"
determining whether an event or object, such as a fossil, is older or younger than other events or objects
"fine particles of sand, dust, or mud that are deposited over time by wind or water"