BIOL 1406 Discussion Questions Unifying Concepts in Biology 1 a On the phylogenetic tree shown here label the most recent common ancestor of species 1 and 2 and the common ancestor of all six species included in the tree Circle the tips which represent the six species included in the study b Describe two ways in which other branches could be part of this tree but are just not shown 2 Compare and contrast natural selection with the process that led to the divergence of a wild mustard plant into cabbage broccoli and Brussels sprouts 3 Consider the following statement If the theory of evolution is true then RNA sequences should be very similar in closely related organisms but less similar in organisms that are less closely related On a phylogenetic tree branches that are close to one another represent species that are closely related branches that are farther away represent species that are more distantly related These statements explain the logic behind using molecular sequence data to estimate evolutionary relationships Is this logic sound Why or why not 4 A theory can have 2 meanings one in the context of science and one in the context of English language Define the term theory using both contexts Explain the difference in the two definitions using the cell theory and the theory of evolution by natural selection as examples 5 A friend claims that the food competition hypothesis and the sexual selection hypothesis are not mutually exclusive when explaining why giraffes have long necks that both could be true How would you respond to him her 6 Describe the nature of each of the following and discuss the role of natural selection in each situation a Industrial melanism b DDT resistance in insects c Sickle cell anemia and malaria 7 Discuss the significance of each of the events listed below in the evolution of living things a Primordial reducing atmosphere b Origin of photosynthesis c Increase in atmospheric oxygen and the development of the ozone layer d Origin of eukaryotes 8 List in order from smallest to largest the 13 hierarchical levels of organization identified in chapter 1 and briefly define each level 9 Explain the theory of natural selection 10 Discuss how each of the following provides evidence for evolution A B C D E F G the fossil record the age of the earth the mechanism of heredity comparative anatomy molecular evidence molecular clocks phylogenetic trees 11 Explain the following core themes of biology A B C D the cell theory the molecular basis of inheritance evolutionary change evolutionary conservation 12 Around the world a handful of scientists are trying to create life from scratch and they re getting closer Experts expect success within 3 to 10 years from someone in the now little known field of wet artificial life If an announcement were made how would you determine if these scientists were actually successful In other words in order to be considered truly alive what features or characteristics would have to be present in what they created 13 A typical bacterial cell has about 3 000 genes while a human cell has about 25 000 genes About 1 000 of these genes are present in both types of cells A How do biologists explain the fact that such different organisms have approximately 1 000 genes in common B How do biologists explain the differences between the bacterial genome and the human genome 14 Decide to which kingdom and domain the following organisms belong to multiple answers may exist A Multicellular contain a nucleus in their cells and that live by eating other organisms B Fresh water organisms that have nucleated single cells C Organisms that contain membrane bound organelles D Some time ago a single celled organism without any nucleus was discovered near deep ocean vents E Autotrophic F Eukaryotic producer G Unicellular photosynthetic eukaryotic organism 15 Arrange the following terms to correctly represents the biological hierarchy of organization from lowest to highest Water Hydrogen cellular nucleus heart muscle cells heart muscle tissue human heart