mod 5 Flashcards
What are the characteristics of index fossils?
Index fossisl are fossils of organisms that lived all over the world (such as throughout the oceans), but only flourished for a relatively short period of time.
Widespread & live for a short period of time
what is the process of urey and miller experiment?
A closed system with several glass chambers was set up
electricity was used to stimulate molecules
upper chambers held methane, ammonia, water vapour and hydrogen gas mimics atmosphere at time
lower chambers represented the ocean and contained water
after a week of continuous electrical charge, water became red and dirty and a number of amino acids were found in water
What are black smokers?
underwater geothermal features found on the ocean floor. dark appearance, caused by the presence of minerals and sulphide deposits expelled from the vents along with hot, mineral-rich fluids. Black smokers typically located in areas where tectonic plates are spreading apart, such as along mid-ocean ridges.
How did the changes to the biosphere affect the Earth’s GEOSPHERE?
- Banded iron formations are layered sedimentary deposits of alternating layers of iron-rich and silica-rich layers.
- They indicate the presence of dissolved oxygen in the ocean, which reacted with dissolved iron when the oxygen was being replenished by the photosynthesizing organisms such as cyanobacteria.
- Silica reacted with silica and created chert, a white layer, contrasting the red, iron-rich layer.
How did the changes to the biosphere affect the Earth’s ATMOSPHERE?
How did the changes to the biosphere affect the Earth’s HYDROSPHERE?
What are some types of fossils?
Cast and Molds
Mineralization
Amber
Trace
How are cast and mold fossils formed?
In many cases, hard body parts (shells or bones) are preserved in sediments but slowly dissolve, leaving perfect “mold” cavities in the rock. The shell is long gone, but it leaves a perfect imprint.
What is the difference between cast and mold fossils?
If the cavity is filled with minerals, it will form a “cast” rather than a mold.
how do black smokers provide evidence for the origins of life?
Hydrothermal vents found were also catalysts, the amino acids found around black smokers formed unique life forms that fed on bacteria that used chemosynthetic processes instead of photosynthetic pathways. The fossils found around black smokers are around 1.3 billion years of age which provides more evidence to the theory that life originated at the bottom of the ocean
What is fossil?
Fossil are the preserved remains or traces of living things and are formed when living things die and are rapid buried by sediments.
Why rapid burial can form fossils?
Burial in sediment project the remains of organism from physical processes that might break it apart and organisms that might consume it. burial also reduces the availability of oxygen for oxygen-powered respiration, which is more efficient and rapid than anoxic processes.
What is panspermia?
theory that life originated somewhere else and travelled to earth on meteorites or asteroids
limitations of the urey and miller experiment
- The experiment failed to explain how proteins were responsible for the formation of amino acids.
- A few scientists have contradicted that the gases used by Miller and Urey are not as abundant as shown in the experiment.
What other conditions can form fossils?
Other conditions that produce well-preserved fossils include the entombment and mummification of whole animals, plant fragment,spores and pollen in tree sap.
