Chapter 12 Quiz

Sedimentary Rock

The place most fossils form

Permineralization

The process in which minerals carried by water are deposited around a hard surface, creating a fossil

A natural cast or impression

Flowing water removes all the original tissue, forming this

Trace Fossils

Fossils showing the activity of an organism, like footprints

Amber-Preserved Fossils

Fossils trapped in tree resin that hardens after the tree is buried

Preserved Remains

The fossil forming when an organism becomes encased in a material like ice

Relative Dating

Estimating the time an organism lived

Compare the placement of fossils in layers of rock

The way scientists estimate fossil age using relative dating

Radiometric Dating

The process of using unstable isotopes to estimate the age of an organism

Isotopes

Atoms that differ in the number of neurons that decay over time

Half-Life

The amount of time it takes for half of the isotope to decay & be replaced

Eras

Periods of time lasting tens to hundreds of millions of years

Period

Each era consists of two or more of these

Epochs

Periods of time lasting several million years

Mass Extinctions or Explosive Radiations

How scientists determine when a new time period occurs on the Geologic Time Scale

3\.8 billion years ago

The first organisms appeared at this time

Prokaryotic

The first organisms were _______

Endosymbiosis

The first eukaryotic cells evolved through this process

A bacteria another cell absorbed

The first mitochondria evolved from this

Genetic Variation

The biggest advantage of sexual reproduction

Paleozoic Era

The era in which multicellular organisms appeared

Cambrian Explosion

The period in which a diversity of water animals appeared

Middle of the Paleozoic Era

Amphibious animals appeared during this period

Mesozoic Era

Reptiles radiated during this era

Mesozoic Era

The first mammals evolved during this period

Cenozoic Era

Mammals radiated during this period

Mammals, forward-facing eyes, enlarged brains, rotating arms, long lower limbs, and opposable thumbs

Characteristics of primates

Prosimians & Anthropoids

2 main groups of primates

Lemurs

An example of prosimians

Old World Monkeys, New World Monkeys, & Hominoids

Groups of anthropoids

Hominids, Great Apes, & Lesser Apes

Groups of hominoids

Big brains, thin faces, long thumbs, & bipedal

Characteristics of hominids

Australopithecus & homo

Groups of hominids

Homo Sapiens

The species name of modern humans

200,000 years ago

Modern humans evolved this long ago

Use of tools & larger brains

Characteristics of homo sapiens

Era, period, epoch

Measures of time on the geologic time scale from longest to shortest