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MBIO 3401 EXAM 3 NEWEST 2025 ACTUAL
EXAM COMPLETE 100 QUESTIONS AND
CORRECT DETAILED ANSWERS (VERIFIED
ANSWERS) |ALREADY GRADED A+|BRAND
NEW!!### Conditions for Life and Early Life Evidence
**QUESTION: What are the fundamental conditions required to
sustain life?**
Answer: 1. Essential elements, 2. Continual source of energy
(sun), 3. Temperature range permitting liquid water.
**QUESTION: What is another name for "evidence of early
life"?**
Answer: Biosignature.
**QUESTION: What are three biosignatures?**
Answer: 1. Isotope ratios, 2. Stromatolites, 3. Microfossils.
**QUESTION: What is a stromatolite?**
Answer: Layers deposits (cyanobacteria) formed by the growth
of blue-green algae.
**QUESTION: What is prebiotic soup?**
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Answer: Blend of gases forming a broth when exposed to light
or heat then forming the building blocks of life.
**QUESTION: What are the models for the first cells?**
Answer: 1. Prebiotic soup, 2. Early oxidation-reduction
reactions, 3. RNA world.
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### Evolution and Divergence
**QUESTION: How did organisms diverge from each other?**
Answer: 1. Random mutations, 2. Natural selection, 3.
Reductive (degenerative) evolution.
**QUESTION: What is a molecular clock?**
Answer: Method used by researchers that uses mutation rates in
DNA to estimate the length of time that two species have been evolving independently.
**QUESTION: What is the most widely used molecular
clock?**
Answer: The gene encoding the small subunit rRNA (SSU
rRNA).
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**QUESTION: What does DNA sequence alignment
compare?**
Answer: The similarity and identity of amino acids and DNA.
**QUESTION: What are the three domains of life?**
Answer: Bacteria, Archaea, Eukarya.
**QUESTION: What is the criteria for a working definition of a
species?**
Answer: 1. SSU rRNA greater/equal to 95%, 2. Avg. nucleotide
identity of ortholog genes greater/equal to 95%, 3. Shared ecotype between organisms greater/equal to 95%.
**QUESTION: What is vertical gene transfer?**
Answer: Transmission of genes from parent to offspring.
**QUESTION: What is horizontal gene transfer?**
Answer: Acquisition of genes from another organism in the
same generation.
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### Ecological Interactions