Mass extinction - Answers crisis that affects all forms of life
- at least 30% of earth's species (ALL NOT JUST ONE) must be lost
- must be across a broad range of ecologies, not restricted to any one niche and not just one species
- it must have a short/sudden duration (1 mil years max)
biosphere - Answers thin layer of life on the surface of the planet that interacts with the hydrosphere
(oceans/lakes/rivers) atmosphere and lithosphere
Biostratigraphy
- 5 concepts - Answers - interpretation of geological record in rocks
1. Principle of Superposition
- rock layer at the bottom of a pile of layered rocks will be the oldest and top layer will be the youngest
2. Principle of Original Horizontality
- b/c of gravity, layers of sediment are originally deposited in the horizontal position
- the older it is, the more folded, tilted it becomes
3. Principle of Lateral Continuity
- sediments extend out laterally in space in a continuous formation
- if formation is separated by a valley or if there is a missing portion but both sides have similar rocks,
then they must have been originally continous
4. Principle of Cross-cutting relationships
- rock feature that cuts thru another rock feature is younger of the two
,5. principle of faunal succession
- species evolve thru time so appearance and disappearance of fossils is used to subdivide geological
time
- each fossil has a range through time --> it exists in the geological record from the point that it evolves
to the point it becomes extinct
Which of the following statements is TRUE?
A) The lithosphere does not interact with the biosphere.
B) Ecosystems are only composed of land based creatures.
C) The biosphere is only composed of plants.
D) Plants often form the base of ecosystems.
E) The biosphere is composed of the atmosphere and the hydrosphere. - Answers D
e- biosphere interacts with atmosphere and hydrosphere does not contain them
1. The principle of faunal succession can be used to correlate rocks because ______. (select the MOST
appropriate answer)
A) all sedimentary rocks were originally horizontal
B) the biosphere is composed of ecosystems
C) life and the biosphere have evolved over time
D) dinosaurs evolved in the Mesozoic
E) unconformities may cross-cut older rocks - Answers C
. Which of the following fossil ranges would provide the greatest RESOLUTION in biostratigraphy? A
fossil species that ______.
A) is found throughout the Phanerozoic
, B) is found throughout the Paleozoic
C) evolves and goes extinct in the Cretaceous
D) evolves in the early Mesozoic and goes extinct in the late Mesozoic
E) evolves in the Cretaceous and is still found today - Answers resolution better for smaller range of
years
A - phanerozoic = 500 mil years
B - 240 mil years
C - 72 mil years
D - 180 mil years
E - 138 mil years
ANS: C
How many years ago where dinosaurs alive? - Answers 250-60 mil years ago
Explain how James Ussher and George Cuvier contributed to the geological time scale - Answers james
ussher - archibishop --> calculatd earth to be 6000 years old
- idea of extinction was not accepted b/c that would suggest god's creation was incomplete
george cuvier - examined remains of mammooths and concluded that there were once living species
that had become extinct
How old is the Earth? - Answers 4.6 billion years old
How is earth's time scale divided? - Answers 1. main groups - eons
- precambrain and phanerozoic
- precambrian occupies like 11/12 of the time, phanerozoic is very small
- this is due to proliferation of fossils in the cambrain (beginning of phanerozoic) --> animals with hard
shells more readily form fossils