Tracing Evolutionary History Flashcards
when was Earth formed
4.6 billion years ago
characteristics of Earth
- thick atmosphere
- high UV radiation
- high volcanic activity and atmospheric electricity
define a stromatolite
layered sedimentary formations that are created by photosynthetic cyanobacteria
stromatolites formed by ______ date back to ______ ______ years ago.
- prokaryotes
- 3.5 billion
what is necessary for cellular life?
- synthesis of amino acids and nitrogen bases
- joining of polymers to make proteins/nucleic acids
- packing molecules into protocells
- origin of self-replicating molecules that made inheritance possible
What was the Oparin-Haldane hypothesis?
conditions on early Earth could have generated organic molecules
describe the abiotic synthesis of organic molecules
h2o -> water vapor -> atmosphere (charged by lightning) -> condensed -> presence of essential amino acids in sample
What other hypothesis have been generated for the origin of organic molecules on Earth?
space and under the sea
Formation of the first cells likely occurred through ______ ______ of _____ and ____ _____ ____.
- abiotic synthesis
- protocells
- self replicating RNA
formation of first cells also could’ve happened by ______ _______ that acted on protocells containing ________ _____.
- natural selection
- self-replicating molecules
the abiotic synthesis of protocells and replicating RNA contains what steps?
- abiotic synthesis of polymers
- formation of protocells
- self-replicating RNA
describe abiotic synthesis of polymers
nucleotides form nitrogenous bases
describe formation of protocells
- lipids condense in water
- naturally form vesicles
- absorb nucleotides and molecules
describe development of self-replicating RNA
through RNA polymerase or similar ribosomes
define macroevolution
evolutionary change at the species level
macroevolution encompasses:
- origin of a new group through speciation events
- impact of mass extinctions (life diversity) and its recovery
define radiometric dating
-used to establish a geological record of Earth’s history through the decay of radioactive isotopes
define a half-life
time it takes for half of an isotope’s concentration to decay
what is an archive of evolutionary history
the fossil record
how have geologists established a geologic record?
ages of rocks/fossils and based on fossil record sequence
In the geological record, how are eras and periods separated and what causes these separations?
how- by major transitions in life-forms
caused- by extinctions
first fossil cells…
3500 mya
photosynthesis
2700 mya
first eukaryotes…
1800 mya
diversity of soft-bodied animals…
600 mya
first land plants and fungi
470 mya
first angiosperms
125 mya
end of cretaceous entinction
66 mya
the history of Earth has been shaped by
plate tectonics
what is the supercontinent and about how many years ago did it exist?
- pangaea
- 250 mya
what affected the distribution and diversification of organisms?
the formation and split of pangaea
what is an example of the microevolutionary pattern that occurred when pangaea split?
gondwana vs. laurasia
the 3 turtles, marsupials
in what ways does Techtronic activity imperil life
- causes the formation of mountain ranges
- produces volcanoes and earthquakes
list the 2 major extinctions and what they’re known for
- permian -extreme volcanic activity
2. cretaceous -impact of an asteroid
fossil record shows that it takes _____ _____ _____ for the diversity of life to return to previous level after an extiction.
5-10 million years
what formed the chicxulub crater?
the asteroid that caused the cretaceous extinction (66 mya)
extinction can result in
adaptive radiation
adaptive radiation occurs when…
- colonization of new areas
- appearance of evolutionary innovations
