BIOL 1108
Exam 2- BIOL 1108: Principles of Biology II (Latest 2026/ 2027
Update) Review| 100% Verified Questions & Answer| Grade A.
Cambrian Explosion (the Rise of Animals) - ANS sudden increase in marine animal life;
rapid radiation of animal taxa in the oceans
How long ago did the Cambrian Explosion happen? - ANS 541 million years ago
Number of Mass Extinctions - ANS 5 (The Big Five)
What caused most of the mass extinction events? - ANS "rapid" climate change which
alters atmospheric or ocean chemistry
How long ago did the Permian extinction happen? - ANS 252 million years ago
How many species were lost during the Permian extinction? - ANS 95%
Possible causes of the Permian extinction - ANS asteroid impact, volcanic activity
How long did the Permian extinction last? - ANS 20,000 - 200,000 years
The Permian extinction is an example of ____. - ANS large scale adaptive radiation
How long ago did the Cretaceous extinction happen? - ANS 66 million years ago
How many species were lost during the Cretaceous extinction? - ANS 75%
What likely caused the Cretaceous extinction? - ANS asteroid strike
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What did the Cretaceous extinction start? - ANS The Age of Mammals
K-T boundary - ANS layer of iridium-rich material between rocks of the Cretaceous
period and rocks of the Paleogene period that provides evidence of a meteorite impact
The Sixth Extinction - ANS current mass extinction is caused by humans, transformation
of the landscape, overexploitation of species, pollution, and the introduction of alien
species
7 Requirements for life - ANS 1. Homeostasis
2. Organization (cells)
3. Growth
4. Metabolism
5. Response
6. Adaptation
7. Reproduction
Which experiment tried to recreate life? - ANS Miller-Urey Experiment (1953)
What was the result of the Miller-Urey Experiment? - ANS -organic compounds
produced (hydrocarbons and amino acids)
-concluded that life can not be created; it is much more complicated than just chemicals
What would the earliest cells have needed to survive? - ANS 1. electron or proton
gradients to create ATP for energy
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2. energy to fuel reactions
3. protection from harmful radiation
LUCA - ANS Last Universal Common Ancestor
How long ago did LUCA exist? - ANS about 3.5 billion years ago
When did the Archaea and Eukaryotes common ancestor exist? - ANS at least 2 billion
years ago
Genomics - ANS analyzing and comparing entire genomes of organisms
Genome - ANS the entire genetic profile of a species (all the genes at once)
Genomics of Bacteria and Archaea - ANS 1800 bacterial genomes
843 archaean genomes
355 common genes
What are some of the common genes shared between bacteria and archaea? - ANS - ion
exchange (H2, iron metabolism)
- DNA repair
- No genes to create an ion gradient (has to depend on environment)
-ATP synthase
Domain Characteristics: Nucleus - ANS Bacteria: absent
Archaea: absent
Eukarya: present
BIOL 1108