chapter 17 -1 the fossil recod – Flashcards

Unlock all answers in this set

Unlock answers
question
paleontologists
answer
scientists who study fossils
question
fossil record
answer
information about past life, including the structure of organisms, what they ate, what ate them, in what environment they lived, and the order in which they lived
question
extinct
answer
no longer existing or living
question
relative dating
answer
method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock
question
index fossils
answer
distinctive fossil used to compare the relative ages of fossils
question
half-life
answer
the time required for one half of the atoms of a radioisotope to emit radiation an decay products
question
radioactive dating
answer
the use of half-lives to determine the age of a sample
question
geologic time scale
answer
scale used by paleontologists to represent evolutionary time
question
eras
answer
one of several subdivisions of the time between the Precambrian and the present
question
periods
answer
subdivisions of eras
question
proteinoid microspheres
answer
large organic molecules that form tiny bubbles
question
microfossils
answer
microscopic fossils of unicellular prokaryotic organisms that resemble modern bacteria have been found in rocks more than 3.5 billion of years old.
question
endosymbiotic theory
answer
theory that eukaryotic cells formed from a symbiosis among several different prokaryotic organisms
question
mass extinction
answer
event in which many types of living things become extinct at the same time
question
macroevolution
answer
large-scale evolutionary changes that take place over long periods of time
question
adaptive radiation
answer
process by which a single species or small group of species evolves into several different forms that live in different ways; rapid growth in the diversity of a group of organisms
question
convergent evolution
answer
the process by which unrelated species become more similar as they adapt to the same kind of environment
question
coevolution
answer
process by which two species evolve in response to changes in each other
question
punctuated equilibrium
answer
pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change
question
what is the fossil recored
answer
the fossil record provides evidence about the history of life on earth.it also shows how different groups of organisms,including specie, have changed
question
what do paleontologist do?
answer
They collect fossils and infer what past life forms were like.
question
what does yhe fossil tecord reveal"
answer
...provides evidence about the history of life on earth. It also shows how different groups of organisms, including species, have changed over time.
question
Describe how most fossils are formed?
answer
Most fossils are formed in sedimentary rocks. And the particles are carried by streams and rivers into lakes or seaswhere they eventually settle to the bottoms.
question
How is sedementary rock formed?
answer
It is formed whenexposure to rain, heat, wind and cold breaks down existing rock into small particles of sand, silt, and clay.
question
Why is the fossil record described as an incomplete record of lifes history?
answer
Because the formation of any fossil depends upon the precise combination of conditions. For every organism that leaves a fossil, many more die without leaving a trace.
question
what do paleontologist do when they study fossils?
answer
They unearth the remains of entire organisms. Sometimes they reconxtruct an extinct species from a few fossil bits, the look foranatomical differences and similarities betwwen the fossil and the living organism.
question
Name two techniques that paleontologist use to determine the age of fossils.
answer
...relative dating and radioactive dating
question
Radioactive decay
answer
the spontaneous disintegration of a radioactive substance along with the emission of ionizing radiation
question
What two things do researchers compare to determine when an organism lived?
answer
By comparing carbon 14 which begins to decay when a thing dies to carbon 12 which is not radioactive and does not decay, scientist can determine when a organism lived.
question
What does geologic time represent?
answer
It represents evolutionary time.
question
What does geologic time begin with?
answer
Precambrian time which civers about 88% of the earths history.
question
Identify three eras that geologist use to divide time?
answer
Paleozoic Mesozoic Cenozoic
question
Paleozoic era
answer
Began 544 million years ago and is the period in which many vertebrates and invertebrates lived.
question
Mesozoic era
answer
middle life (245-144 million years ago); rise of mammals and dinosaurs; the rise of birds; extinction of dinosaurs, rise of flowering plants
question
Cenozoic era
answer
the latest of the four eras into which geologic time is subdivided ; 65 million years ago to the present: sometimes called the age of the mammels.
question
What type of dating provides abosulte age for a given fossil?
answer
Radioactive dating
question
How are eras and periods related?
answer
Eras are subdivided into periods which range in lenght frim tens of millions of years toless than two million years.
question
How do fossils form?
answer
Most fossils form when organisms that die become buried in sediments.
question
What geologic era is known as the age of mammals?
answer
Cenozoic
question
Identify the three periods included in mesiozoic era.
answer
Triassic Jurassic Cretaceous
question
Cambrian period
answer
from 544 million to about 500 million years ago
question
Identify the six periods that existed during the paleozoic era.
answer
Cambrian Ordovician Silurian Devonian Carboniferous Permian
question
Identify the two periods during the cenozoic era.
answer
Quaternary Tertiary
Get an explanation on any task
Get unstuck with the help of our AI assistant in seconds
New