Chapter 23: History Of Life Flashcards
Stratigraphy
- Study of rock layers
- Layers reveal patterns of evolution and age of fossils
- Fossils toward the top are younger and are more similar to modern organisms
Radiometric dating
-measures the amount of radioisotopes and daughter element, tells the age of material
Fossil record
- how long animals and plants lived in the past
- how they are related to each other
Magnetic field
Related the age of rocks to patterns in earths magnetism
- magnetic poles move and can reverse themselves
- iron on rock can align w/ magnetic north and preserves the record of magnetic field at the time
What is continental drift? How does it explain environmental change and the distribution of organisms/fossils?
- continental drift is land masses changing position overtime due to plate tectonics moving
- altered ocean patterns, heat in the atmosphere, and formed mountains
- explains why same fossils are found in different continents
Why is continental drift considered a driving force of evolution
Animals had to adapt to the change of environment in order to survive
What are plate tectonics? How does it tie into continental drift?
-mechanism to continental drift
-sea floor spreading/ rifts: new rocks comes from earth interior and pushes the old rock outward
Subduction zones/trench: old rock plunged into trench and remelts into earths interior and one plate is pushed under the other
How does a change in the geology of earth affect the environment? How does it affect organisms
- it affects ocean circulation/ patterns,global climates, glacial patterns
- glaciers form(glacial advance) causes cooler climates
- glaciers melt releases water causes warmer climates
- change in ocean depth/sea level
- animals have to adapt
Climate vs weather/ causes of current climate shift
- weather are daily events at a specific location(changes fast)
- climate is long term and averages over seasons at a specific location (changes slowly)
- current climate is rapid change organisms don’t have time to adapt, temperatures fluctuate due to negative impacts on environment
Major climate/ environmental disruptions/ how do they change environment
-volcanoes: the larger the eruption the more effect on life. They block sunlight from plants(affects the food chains) lower global temp, Change in weather patterns
Meteor impacts: brought new elements to earth, caused the K-T extinction
What is the K-T(Cretaceous-Tertiary) extinction event? How did it change the environment and what is the evidence?
- meteor that killed the dinosaurs by blocking sunlight heated debris caused massive fires across earth and tsunamis
- the evidence is there is an iridium layer that can be found by Mexico, layer of soot w/ composition, SUDDEN DISAPPEARANCE OF ORGANISMS not found in the fossils or strata
What are the 2 eons
Precambrian and Phanerozoic
Precambrian: Snowball earth, seas and continents were covered by ice life was confined to warm areas limited diversity
Phanerozoic: we live in this period oxygen concentrations increased, continents formed many species appeared(Cambrian explosion)
Order of era and periods
Eras: Paleozoic, Mesozoic, Cenozoic
Periods: (first to last) Cambrian Ordovician Silurian Devonian Carboniferous Permian Triassic Jurassic Cretaceous Tertiary (ice age) Quaternary (current)
Cambrian
- life is in the ocean
- restricted to microorganisms
- most diverse were crustacean arthropod (trilobite species)
Ordovician
- land has no multicelular life
- evolutionary radiation of marine life (mollusks and brachiopods)
- was ended bu the Ordovician mass extinction( massive glaciers formed, 75% of population extinct)
