1. Unit 3: Evolution Test
Study Guide Answers

2. First cells- prokaryotic and heterotrophic
Half life
How do you calculate it? Divide the amount in half
How is the age of a fossil determined? Measuring the amount of a radioactive isotope in the fossil bones
First cells- prokaryotic and heterotrophic
Fossil examples- shells or old bones, traces of dead organic matter, insects trapped in tree sap
Darwin
Where did he travel? Galapagos Islands
What did he learn about finches? They came from a common ancestor but had different beak lengths.
Why does evolution occur? Because of natural selection
Adaptation- process by which an organism becomes better suited to its environment

3. Natural selection- process by which organisms well suited to their environment survive and reproduce
Homologous structures- provide evidence that organisms share a common ancestor
Phenotype frequency= # of individuals with a particular phenotype / total # individuals
Hardy-Weinberg equilibrium- no change in a population
Genetic drift- occurs in small populations; alleles decrease in frequency due to chance
Disruptive selection- eliminates the intermediate phenotype
Directional selection- a change in the frequency in a gene in one direction
Gradualism- hypothesis that evolution occurs at a slow, constant rate

4. Taxonomy- the science of classifying living things
Biological hierarchy
How do we name species? Genus and species
Correct order of hierarchy- Kingdom, Phylum, Class, Order, Family, Genus, Species
Phylogenetic trees- depict evolutionary relationships based on a variety of types of evidence
Bacteria
How are they characterized? As prokaryotic
Describe a bacterial cell. Cytoplam contains a single chromosome; have a cell membrane and cell wall
Prokaryotes- simple; no nucleus; no membrane-bound organelles; do have a region of DNA

5. **Know how to work a Hardy-Weinberg problem!*
Virus
How do they reproduce? Reproduce only in living cells
Why were they first studied? b/c they could not be seen but caused disease
Describe the capsid- protective outer coat of the virus
Why are they not considered living? They can only reproduce in a living host—use your knowledge from the virus webquest
Shapes of bacteria
What is a spiral one called? Spirillium
What is a spherical one called? Cocci
What is a rod-shaped one called? Bacilli
**Know how to work a Hardy-Weinberg problem!*