-1stLivingThingsLEC22 Flashcards
What does it means for something to be organic?
It has carbon.
Explain something that Polymerize.
When do small organic molecules do this?
Ex. Plastic
They combine into chains.
When they are concentrated on hot rocks.
What are Protobionts?
They form spontaneously from what?
Clusters of molecules surrounded by a membrane-like structure.
Organic compounds.
What is an example of Protobionts?
Liposomes
What are liposomes? how are they form?
-Membrane-bound droplets.
-when organic lipids are added to water.
・Happens in our salad dressing.
True or False? Liposomes has simple reproduction, they “give birth” to smaller liposomes.
TRUE
Explain the simple “metabolic” reactions that some liposomes carry out.
They break down molecules and gain energy.
What are the 4 steps for creating life?
1) The formation of organic molecules.
2) These joining into polymers.
3) Then collecting into protobionts, with membranes.
4) The origin of self-replicating molecules that made inheritance possible.
What was probably the first genetic material?
RNA
What can RNA do with sections of themselves?
Copy them
RNA sequences can what?
What sequences multipy?
Evolve
Ones that are more stable than others.
Protobionts with self-replicating RNA would have what?
Been better at using resources & multiplied through natural selection.
Once RNA sequences carrying genetic information appeared, what further changes were possible?
The origin of the double-helix DNA.
It is more stable & can be replicated more accurately.
What are index fossils, and what do they allow us to do?
Similar fossils found in the same strata.
Allow us to date strata at different location.
How does radiometric dating work?
When an organism dies, it’s carbon-14 slowly decays (loses neutrons) until it become nitrogen-14. By measuring the nitrogen-14, a fossil’s age can be determine.
When an organism is decaying, carbon is turned into nitrogen, but carbon will never go away. Why?
They have half-lives, so carbon will never reach zero.
What can also provide dating information of fossils?
Magnetism of rocks
When do the magnetic reversals of poles occur, leaving their records in rocks?
Roughly every 400,000 years
Scientists believe that a magnetic pole reversal is imminent and we shouldn’t take it lightly. Why?
The magnetic field is reducing which will leave us vulnerable to solar radiation.
By studying fossils at many sites, geologist have peaced together a Geologic Record of Earth’s history.It is divided into 4 eons, what are they?
Hadean
Archaean
Proterozoic
Phanerozoic
True or false? Each time period ends with major changes in fossils.
TRUE
Hadean
Began 4.5 bya
Earth & solar system was form
Archaean
Began 3.9 bya
Life arose on Earth.
Proterozoic
Began 2.5 bya
Oxygenated atmosphere was developed.
Multicellular life arose.
Phanerozoic
Began 540 mya
Cambrian explosion?
True or False? Fossil record shows many extinctions, & we are in a process of another massive one.
TRUE
What are two mass extinctions that are best known?
The Permian & Cretaceous extinction.
Permian extinction
Happened 248 mya
Killed 96% of marine species
May have been caused by volcanic eruptions.
Cretaceous extinction
Happened 65 mya
Killed half of all known organisms
Thought to been caused by a huge meteor
What opportunities did mass extinction provide?
Adaptive radiation into newly vacant ecological niches.
