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Biology Vocab

Chapter 12

TermDefinition
Relative Dating Estimate of the age of a fossil based on the location of fossils in strata.
Radiometric Dating Technique that measures the natural decay rate of isotopes to calculate the age of material.
Isotope Form of an element that has the same number of protons but a different number of neutrons as another element.
Half Life Amount of time it takes for half of the isotope in a sample to decay into its product isotope.
Index Fossil Fossil of an organism that existed during only specific spans of geologic time across large geographic areas.
Geologic Time Scale Time scale representing the history of Earth.
Era Second largest unit of geologic time, lasting tens to hundreds of millions of years and consisting of two or more periods.
Period Unit of geologic time that lasts tens of millions of years and is associated with a particular type of rock system.
Epoch Smallest unit of geologic time, lasting several million years.
Nebula Rotating cloud of gas and dust.
Ribozyme RNA molecule that ca catalyze specific chemical reactions.
Cyanobacteria Bacteria that can carry out photosynthesis.
Endosymbiosis Ecological relationship in which one organism lives within the body of another.
Paleozoic Era of geologic time (from 544 to 248 million years ago) during which members of every major animal group alive today evolved.
Cambrian Explosion Earliest part of the Paleozoic era, when a huge diversity of animal species evolved.
Mesozoic Era during which dinosaurs roamed Earth (from 248 million years ago to 65 million years ago).
Cenozoic Geologic time period that began 65 million years ago and continues today.
Primate Mammal with flexible hands and feet, forward-looking eyes, and enlarged brains relative to body size.
Prosimian Oldest primate group that includes mostly small, nocturnal primates such as lemurs.
Anthropoid Humanlike primate.
Hominid Primate that walks upright, has long lower limbs, thumbs that oppose the other four fingers, and a relatively large brain.
Bipedal Animal that walks on two legs.
Created by: 58knasims