How can we help?

You can also find more resources in our Help Center.

45 terms

Biology Chapter 12 All

Biology Chapter 12 Whole Chapter for Test
STUDY
PLAY
permineralization
occurs when minerals carried by water are deposited around a hard structure.
natural casts
form when flowing water removes all of the original bone or tissue, leaving just an impression in sediment.
trace fossils
record the activity of an organism; they include nests, burrows, imprints of leaves, & footprints.
amber-preserved fossils
organisms that become trapped in tree resin that hardens to amber after the tree gets buried underground.
preserved remains
form when an entire organism becomes encased in material such as ice or volcanic ash or immersed in bogs.
sedimentary
most rocks form in ______ rock.
permineralization
the most common fossils result from _________.
relative dating
_______ _______ estimates the time during which an organism lived by comparing the placement of fossils of that organism with the placement of fossils in other layers of rock.
radiometric dating
_______ _______ is a technique that uses the natural decay rate of unstable isotopes found in materials in order to calculate the age of that material
isotopes
________ are atoms of an element that have the same number of protons but a different number of neutrons.
half-life
______ is the amount of time it takes for half of the isotope in a sample to decay into a different element or its produce isotope.
4.5 billion
How old is earth in years?
index fossils
fossils of organisms that existed only during specific spans of time over large geographic areas.
geologic time scale
the _____ _____ ___ is a representation of the history of Earth.
Eras
________ last tens to hundreds of millions of years and consist of two or more periods.
Periods
_______ are the most commonly used units of time on the geologic time scale, lasting tens of of years; each ______ is associated with a particular type of rock system (same word).
Epochs
________ are the smallest units of geologic time and last several million years.
nebula
a _________ is a cloud of gas and dust in space.
Ribosymes
____________ are RNA molecules that can catalyze specific chemical reactions.
5700
Carbon 14 has a half life of roughly ____ years.
Nitrogen
Carbon 14 decays into what other element?
45,000
Carbon 14 may be used to date objects up to ______ years old.
meteorites
Scientists use _________ to determine the age of the earth.
fusulinids
An example of an index fossil are the extinct marine invertebrates known as _________.
ancient life
Paleozoic means _______ ________.
middle life
Mesozoic means _____ ______.
recent life
Cenozoic means ______ ______.
Hadean Eon
The time on earth that was very hot (the first 700 million years)
2
Most scientists agree that free oxygen was not abundant until about __ billion years ago.
RNA
Recent studies show that ___ may have been the genetic material on early earth instead of DNA.
Ribozymes
______ can catalyze their own replication and synthesis.
cyanobacteria
bacteria that can carry out photosynthesis.
stromatolites
_______ are domed, rocky structures made of layers of cyanobacteria and sediment.
Endosymbiosis
a relationship in which one organism lives within the body of another, and both benefit from the relationship.
asexually
The first prokaryotes and eukaryotes could only reproduce _______.
sexual reproduction
___ ___ may have been the first step in the evolution of multicellular life.
Cambrian Explosion
The earliest part of the Paleozoic era when a huge diversity of animal species evolved.
carboniferous
Most of the coal used in the US formed during the ______ period of the Paleozoic era.
Mesozoic era
The era known as "The age of Reptiles"
Cenozoic
Which era are we currently in?
Quaternary
What period are we currently in?
Primates
_____ make up a category of mammals with flexible hands and feet, forward looking eyes, and enlarged brains relative to body size.
prosimians
_______ are the oldest living primate group and most are small and active at night.
anthropoids
the humanlike primates; are further subdivided into the New World monkeys, Old World monkeys, and hominoids.
Hominids
_____ walk upright, have long lower limbs, thumbs that oppose the other 4 fingers, and relatively large brains.