Podcast
Questions and Answers
The first fossil evidence of life is found in ______, which are layered sedimentary rocks formed by ancient cyanobacteria.
The first fossil evidence of life is found in ______, which are layered sedimentary rocks formed by ancient cyanobacteria.
stromatolites
The ______ theory explains that eukaryotes originated from prokaryotes that lived in a symbiotic relationship.
The ______ theory explains that eukaryotes originated from prokaryotes that lived in a symbiotic relationship.
endosymbiotic
Similarities in enzyme and transport systems between prokaryotes and ______ support the endosymbiotic theory.
Similarities in enzyme and transport systems between prokaryotes and ______ support the endosymbiotic theory.
mitochondria
In the geologic time scale, eons indicate a duration of hundreds of million ______.
In the geologic time scale, eons indicate a duration of hundreds of million ______.
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Natural selection works by selecting ______ that confer specific traits or behaviors.
Natural selection works by selecting ______ that confer specific traits or behaviors.
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A ______ is a change in the gene sequence that can affect allele frequency.
A ______ is a change in the gene sequence that can affect allele frequency.
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Genetic drift stems from the chance occurrence that some individuals have more ______ than others.
Genetic drift stems from the chance occurrence that some individuals have more ______ than others.
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Present prokaryotes and endosymbionts have similar ______ structures, which support the endosymbiotic theory.
Present prokaryotes and endosymbionts have similar ______ structures, which support the endosymbiotic theory.
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Study Notes
Earth and Early Life Forms
- Stromatolites: Layered sedimentary rocks formed by ancient cyanobacteria. These are the earliest fossil evidence of life.
Endosymbiotic Theory
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Explains that eukaryotes originated from prokaryotes in a symbiotic relationship.
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Evidence Supporting Endosymbiotic Theory:
- Prokaryotes have similar enzyme and transport systems to those of mitochondria and plastids.
- Binary fission, a prokaryotic reproduction method, is similar to the splitting mechanisms of endosymbionts.
- Both possess circular DNA and similar protein types (with few or no histones)
- Endosymbionts have machinery to transcribe and translate DNA into proteins similar to prokaryotes
- Prokaryotes and endosymbionts share similar ribosome structures.
Divisions of Geologic Time
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Geology Time Scale: A record of Earth's history, from 2.5 billion years ago (mya) to the present.
- Eras: Long spans of time (hundreds of millions of years)
- Hadean Eon
- Archaean Eon
- Proterozoic Eon
- Phanerozoic Eon
- Eras: Long spans of time (hundreds of millions of years)
Mechanisms of Evolution
- Evolution: The process by which changes in plants and animals happen over time.
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Natural Selection:
- Works by selecting alleles that confer beneficial traits or behaviors.
- Based on the variation in the abundance of certain alleles within a population.
- Mutation: A change in the DNA sequence of a gene that can change one allele into another, potentially affecting the phenotype (observable characteristics). Neutral mutations have no effect on fitness, while harmful mutations are removed, and beneficial ones spread.
- Genetic Drift: Changes in allele frequencies due to random events, like some individuals having more offspring than others.
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Description
Test your knowledge on the early life forms on Earth, including stromatolites and the endosymbiotic theory. Explore the evidence supporting the origins of eukaryotes and the divisions of geologic time. This quiz covers key concepts and historical timelines relevant to Earth's life forms.
