Topic 9: The Origin Of Life Flashcards
Adaptation
The ability to change over time in response to the environment
What is a virus
A parasitic entity that exploits an organism to do basic functions.
What do viruses have
Nucleic acids to replicate, mutate and respond to natural selection
What do viruses lack?
Metabolism, homeostasis, and cant reproduce
Do we consider viruses to be alive
No
Three eons of geologic records
Archean, proerozoic and phanerozoic
______ includes the last half billion years and ecompassesses multicellular eukaryotic life
Phanerozoic
List the three eras of the phanerozoic eon
Paleozoic, mesozoic and cenozoic
_____ provides evidence of evolutionary history
Fossils
Fossil records are _____ and ____
Biased, incomplete
Why are fossils biased and incomplete?
- not all organisms were fossilized
- require burial sediment to form
- some organisms were fossilized under some conditions
Types of fossil records
Cast, replacement, trace or preserved fossil
Fossil type formed when minerals fill space in sediment where organisms decays, making a mold of the organism
Cast
Fossil type where fossils have their tissues replaced by minerals
Replacement (petrified fossils)
Fossil that record evidence of behaviour such as footprints, burrows, feces
Trace
Fossil type that retain orginial organic materual (carbon films, amber, frozen, etc)
Preserved
Two ways to determine the age of a fossil
Relative dating and radiometric dating
Relative dating
Analyzing and comparing positions of sedimentary strata. Helps tells which fossil came first, second, third
Challenges to relative dating
- Sediments become tipped or shifted during land movements
- gaps in the sediment
- does not provide the absolute age of a fossil/ how long it was created
Radiometric dating (absolute dating)
Analyzing the radioactive decay and the half life of isotopes (example carnbon 14 and carbon 12, potassium dating)
Plate tetonic theory
Theory that earths crust is composed of large plates that have been moving slowly through continential drift around 3.4 billion years ago
______ causes tectonic plates to collide, separate or slide past eachother
Continential
Interactions between different plates/ continential drift cause:
Mountains, islands, earthquakes
Tectonic boundaries are sites of…
Volcanoes, earthquakes
What are the three consequences during than phanerozoic era
1.) Formation of pangea reduced shallow water habitats , colder and drier climate inland, deepining of ocean basins
2.) influenced biodiversity through mass extinction, change in climate, speciation
3.) distribution of fossils show evidence of geological movement
One way extinction generally occurs
When a species can not adapt properly or respond to changes in the environment
What are mass extinctions a result of
Disruptive global environmental changes
Most fossil records show that most species are extinct. True or false
True
Permian mass extinction
Most severe extinction event that happened between paleozoic and mesozoic era, hypothesied cause was due to volcanic activity, little fossil records
Cretaceous mass exctinction
Separates mesozoic anfrom cenozoic, only 20% of families went extinct , hypothesized cause was through a meteorite impact
What is the 6th extinction and what is the cuase of
Holocene extinction is caused by human activity of overpopulation and overconsumption
Mass exctinction can lead to _____ radiation
Adaptive
What is adaptive radiation
Rapid speciation and diversification of adapted species. Occurs when there is a change in the environment that makes new ecological niches available
3 things that adaptive radiation may arise
1) mass extinction
2) evolution of novel characteristics
3) colonization of new regions
How can adaptive radiation arise from mass extinction?
Eliminating species makes more resources available and paves the way for adaptive radiation
What is evolution of novel characteristics
Adaptive radiation and arise of new species such as photosynthetic prokaryotes, land plants, insects, etc
How did life most likely begin
The conditions of early earth caused chemical reactions that gave a arise to molecules of life
Stages that started life
1) abiotic synthesis of small organic molecules (inorganic to organic)
2) organic molecules into organic polymers
3) packaging molecules into protocells
4) origin of self-replicating molecules
Two possible wats or how organic molecules arised
1) terrestrial origins: organic molecule synthesis driven by energy soruces such as UV light and electric discharges
2) extraterrestrial orgin: formation of organic molecules due to extraterrestrial objects coming to earth
Hypothesized causations of abiotic synthesis
The atmosphere rich in methane and ammonia, near volcanic sites, deep sea hydrothermal vents in both reducing and non reducing environments
What is the cause of spontaneous polymerization of organic molecules
Wetting and drying cycles of water on hot surfaces may have caused concentration of small organic molecules into polymers. Minerals trigger polymerization
Protocell
Fluid like vesicle with a lipid bilayer membrane structure that formed spontaneously
Earliest genetic material is hypothesized to be
RNA
Wha was the great oxygenation event
Accumulation of oxygen in the atmosphere due to prokaryotes. Some prokaryokes evolved to be aerobic and anaerobic
