Topic 9: Origin of Life, Prokaryotes, and Protists Flashcards
What are the 6 features of life? (Definition of Life)
- Organization
- Metabolism
- Response to Stimuli
- Homeostasis
- Adaptation
- Reproduction
What is metabolism ?
A system of management of energy and materials via chemical reactions.
What are the three eons of the Geological Record?
Archaean, Proterozoic, and Phanerozoic
What does Precambrian refer to?
Archaean and Proterozoic Eons
What are the 3 sub categories of Phanerozoic?
Paleozoic, Mesozoic, and Cenozoic
What makes an Eon Boundary?
they each correspond to mass extinction
What is the Fossil Record?
Sedimentary Rocks that provide direct evidence of evolutionary history.
What’s wrong with the fossil record?
It is biased and incomplete.
What are the 5 types of fossils?
Mold, Cast, Replacement (petrified), Trace, Perserved.
Mold Fossils
When a hollow space (impression) remains after the organism decays or dissolves.
Cast Fossils
Forms when minerals fill the hollow space, creating a solid replica.
Replacement Fossils
Original tissues are replaced by minerals, preserving the detailed structure of the organism.
Trace Fossils
Provide evidence of an organisms behaviour, such as tracks, burrows, or feces.
Perserved Fossils
Retain most of the original organic material of the organism.
how do we determine the Age of a Fossil?
Relative Dating and Absolute Dating.
Relative Dating
Sedimentary strata layered can indicate relative age of fossils to one another, but cannot get. exact date.
What is an index (indicator) fossil?
A widespread common fossil that has a known age and can be used to reference other fossils found in strata.
Absolute Dating (Radiometric dating)
Radioactive decay of isotopes of various elements provide a means of determining the age of fossils or rocks. (The decay has a known constant rate to give indications)
Half Life
The time required for 50% of atoms in a given amount of isotopes to decay.
What are the three major land formation caused by Continental Drift?
Pangaea, Laurasia, and Gondwana.
Continental Drift
Tectonic plates to collide, separate, or slide past each other creating mountains, islands, and earthquakes. They can majorly effect Earths physical geography/climate and biodiversity.
Mass Extinctions
Result of disruptive global environmental changes. More than 50% of Earths species became extinct.
What were the most important of the 5 main mass extinctions?
Permian and Cretaceous.
Permian Mass Extinction (The Great Dying)
Caused by volcanic activity and gradual environmental changes.
Created the formation of Pangea and defines the boundary between Paleo and Meso Eras.
Cretaceous Mass Extinction
Caused by meteorite impact, which caused dust clouds that blocked out the sun.
Killed the non-avian dinosaurs and separates the Meso and Ceno Eras.
6th Mass Extinction (Holocene Extinction)
A human caused extinction that is ongoing as it decreases biodiversity faster than ever. Driven by population growth and overconsumption.
Adaptive Radiation
Following mass extinctions, this is the rapid evolution of diversity in a set of taxa from an ancestral species. Allows for the Evolution of Novel Characteristics and the Colonization of New Regions.
Evolution of Novel Characteristics
A new trait in a group leads to creation of own new niches/advantages.
Colonization of New Regions
Environments with little competition.
What are the four hypothesized steps of the events leading to life?
- Abiotic Synthesis of Small organic molecules
- Polymerization of Small organic polymers
- Formation of Protocells
- Emergence of Self-replicating Molecules
- Abiotic Synthesis of Small organic molecules
The formation of organic compounds from inorganic precursors through abiotic processes
- Polymerization of Small organic polymers
Small organic molecules can undergo polymerization reactions.
- Formation of Protocells
In water, certain organic molecules can spontaneously form hollow vesicles with a lipid bilayer - creating a protocell.
- Emergence of Self-replicating Molecules
Natural selection produced self-replicating RNA.
What was the first life?
Prokaryokes
Stromalites
The oldest fossil evidence of life.
Great Oxygenation event
When O2 began accumulating in the atmosphere and oceans.
What was the major development that CAUSED the Great Oxygenation event?
Photosynthetic prokaryotes (cynobacteria) evolved to use the sun’s energy to fix CO2 into O2.
