Development of the Biosphere Flashcards
How did today’s biosphere originate and develop?
What did the Urey Miller experiment demonstrate?
Certain organic molecules can form spontaneously under natural conditions (from non-life)
How was the Urey Miller experiments conducted?
Water, methane, ammonia and hydrogen gas was placed in a vacuum chamber. Electrical sparks were used to simulate lightning. The water was then cooled and tested for organic compounds (chromatography)
What molecules were found in the Urey Miller experiment?
Amino acids. In later recreations, more amino acids and organic materials such as adenine were found.
How are black smokers formed and how can it create organic molecules?
Black smokers forms at mid-ocean ridges where seawater seeps into newly-formed crust. This dissolves minerals in the vent, and black chimneys are formed due to precipitates of insoluble materials. This causes unique chemistry and conditions completely independent of the sun, which is not found in surface waters.
What is Panspermia?
Panspermia is the theory that the organic molecules responsible for the development of life or even the first cells themselves arrived on meteorites to the early Earth. However, it does not explain their origins, but the origins to Earth.
How is it proposed that volcanic hot springs are the origin of organic molecules?
The hot spring/freshwater hypothesis is that the interactions between multiple hot springs with varying conditions and chemistry may have formed new molecules
How did photosynthetic life originate on the Earth?
First appeared in the Archaean Eon in cyanobacteria
How are stromatolites evidence of the origin of certain types of life?
They are formed by the molecules released by layers of cyanobacteria which builds up. This can indicate periods of high and low oxygen causing cyanobacteria to flourish
How are animals of the Edicaran characterised?
- Fractional asexual reproduction
- Sexual reproduction
- Microbial mats
- Horizontal tunneling
- Bilateral symmetry
- First confirmed animals
- Avalon explosion
What was the main difference between Ediacaran and Cambrian fauna?
Easily fossilisable parts were only present in the Cambrian
What was the Cambrian Event/”Explosion”? Why was it caused?
A punctuated equilibrium event that occurred after the Ediacaran extinction. Animals had to look for new food sources leading to predation
What is an example of Ediacaran fauna and what are its traits?
Dickinsonia: soft-bodied, range of complexity, lived in shallow/marine waters
What is an example of Cambrian fauna and what are its traits?
Anomalocaris - exoskeleton ‘armor’ to defend from predators, burrowing and ambushing techniques, development and eyes and teeth
