Unit 3: Evolution Test Study Guide Answers

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

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

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

**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!*