8/30 Fossils

Question 1

Paleobiology
Study of:
* _______________ organisms
* Macroevolution, large scale changes in morphology
and diversity
* Discover, describe, and name new __________________

Answer 1

1. ancient
2. Fossils

Question 2

Fossil Record
* Provide _____________
___________ of life in
past
* __________ source of
data about
evolutionary history of
many organisms

Answer 2

2. physical evidence
3. primary

Question 3

Fossils form when organisms are buried by sediments
or preserved in oxygen-_________ environments

-Highest strata
contain most
__________ fossils
-Lowest strata
contain
___________ fossils

Answer 3

1.poor
2.recent
3.oldest

Question 4

• _______________________ like bones, teeth, shells of animals, and wood, leaves, and pollen of plants
• Soft remains ______________ consumed by scavengers or decomposed by microorganisms

Answer 4

1. Hard Structures
2. quickly

Question 5

Fossilization
* Dissolved minerals replace some parts molecule by
molecule, leaving fossil made ________________
* Some form as molds, casts, or impressions in material later turned to ______________________

Answer 5

1.of stone
2.solid rock

Question 6

Fossilization
* ____________ of ____________ prevents decomposition
* Even soft bodied organisms are preserved (ex. plants,
insects, lizards, frogs in amber)
* Others in ______________, frozen soil, coal, tar pits

Answer 6

1.absence of oxygen
2. glacial ice

Question 7

Provides incomplete portrait
of life in the past
* ________________ fossil species
described
* _______ % of all species
* Most common fossils are from
– hard-bodied
– ___________________
– _______________ organisms
– lived near swamps or
shallow seas where
sedimentation is ongoingconda install python=3.7

Answer 7

1. 300,000
2. <1%
3. widespread
4. abundant

Question 8

Fossil Record
* Many ____________ by
pressure of rocks
* ________________ in
geological disturbances
(ex. volcanoes,
earthquakes)
* On earth’s surface, rain
and wind can _________
them

Answer 8

1.deformed
2.destroyed
3.erode

Question 9

Relative Dating
* Give relative
______________________
* Lower layers older than
upper layers
Drawbacks
* Not always deposited in
________________ fashion
* Provide no information
on __________ in years
* Can be large gaps in
geologic record

Answer 9

1.approximate age
2.horizontal
3.age

Question 10

Absolute Dating
* Isotopes and _________________ decay
* Radioisotopes break down at _____________ rates
* _________________ by chemical reactions or
environmental conditions
* Measure relative amounts of
radioisotope
* Compare ratio with the isotope’s
half-life (time it takes for half of
given isotope to decay)
* Estimate age of rock

Answer 10

1.radioactive
2.steady rates
3.unaffeted

Question 11

Fossil Record
Provide abundant information about life in past!
* Fossilized skeletons, shells, leaves, flowers
* _______ and appearance of ancient plants and animals
* Reconstruct vegetation and climate of ancient sites
* How structures ____________________
* Extinction of evolutionary linages
* Geographical _____________________

Answer 11

1.Size
2.modified
3.distributions

Question 12

Historical Biogeography
* Continental drift facilitated in _______________ of distinct
evolutionary lineages in different regions of the world

Answer 12

diversification

Question 13

Isolation of __________________ fostered distinctive biotas

Answer 13

continents

Question 14

Radiocarbon Dating
All ___________ atoms have ____ protons in nucleus
but nucleus may contain 6, 7, or 8 neutrons

Answer 14

carbon
6

Question 15

Carbon-12
* Carbon with 6 protons and 6 neutrons. Stable
nucleus. _____% of all natural carbon is 12C
Carbon-13
* Carbon with 6 protons and 7 neutrons. Stable
nucleus. _____% of all natural carbon is 13C
Carbon-14
* Carbon with 6 protons and 8 neutrons. Unstable
radioactive isotope. About 1 in 10 12 carbon
atoms in atmosphere is 14C

Answer 15

1) 99
2) 1

Question 16

Radiocarbon Dating
* Plants take in cabon-14
through _______________
* Animals eat plants and
take in _______________
* When an organisms dies,
we stop absorbing
carbon-14 and amount
of carbon-14 decrease
through beta decay

Answer 16

1.photosynthesis
2.carbon-14