BIO 1: Exam 4 Essay Questions
Four of these questions will be on the exam and you will choose to write on three out of the four. Each of the three
questions will be worth 10 points on the exam.
1. A) Describe the two principles of evolution that Charles Darwin proposed: 1) Common Descent with Modification and 2)
Natural Selection.
B) Describe what microevolution and macroevolution are.
2. Explain how 1) fossil evidence, 2) evidence from comparing anatomy, 3) evidence from comparing embryos 4) evidence
from molecular biology, and 5) evidence from quickly evolving organisms support the occurrence of evolution.
3. The five agents of microevolution are 1) mutation, 2) gene flow, 3) genetic drift, 4) sexual selection, and 5) natural
selection. Describe how each brings about change in allele frequencies in a population.
4. Two outcomes of genetic drift are the 1) bottleneck effect and 2) founder effect. Describe what each effect is.
5. Using what you learned from the videos “The Making of the Fittest: Natural Selection and Adaptation” and “The
Making of the Fittest: Natural Selection in Humans” answer the following questions:
A) What are mutations dependent on to determine whether they are good or bad?
B) Is evolution a random process? Explain.
C) In a malarial environment what individuals are at a disadvantage and why? What individuals are at an advantage
and why?
D) Using your own words, briefly explain why sickle cell anemia is still prevalent and why in particular in people
of African descent.
6. Using what you learned from the video “The Making of the Fittest: Got Lactase?” answer the following questions:
A) What is the name of the main sugar in milk and what is the name of the enzyme that humans use to break down
this milk sugar?
B) What happens to most young mammals when they stop drinking milk and what is the only mammal species in
which some adults can still drink milk without getting sick?
C) What was found in the DNA of many Europeans and Africans and what did it allow these people to do?
D) What might explain why they each independently evolved this ability?
E) How and why did lactase persistence provide a selective advantage to those that had the trait?
7. Define the following reproductive isolating mechanisms that can stop a population from interbreeding and possibly lead
to the formation of a new species: 1) geographic, 2) ecological, 3) temporal, 4) behavioral, 5) mechanical, 6) gametic,
and 7) hybrid inviability/infertility.
8.
Using what you learned from the three Evolution of Human Beings videos answer the following questions:
A) How are chimps related to humans? Are chimps our ancestors?
B) What is believed to be a reason why walking evolved?
C) State what Homo erectus were the first to do and how did that affect their brains?
D) In general, how did brain size change from Homo habilis to Homo sapiens?
E) Explain why 1 – 4 % of the genes from all living humans outside sub-Saharan Africa (todays Europeans and
Asians) is of Neanderthal origin.
F) According to the math, what is true about every human alive today?
G) Where does our most ancient mitochondrial DNA come from and from whom?
9. State the two main life history patterns of populations and list 4 characteristics that species using each pattern tend to
have. (4 characteristics for each pattern)
MORE QUESTIONS ON BACK
10. A) Describe the three reasons, that we discussed, that explain why predator/prey interactions are important to have in a
community.
B) Give an example of a predator that we discussed. And describe the cascading effects that occur when the predator is
present versus no longer present in the community.
11. A) Name and describe the two outcomes of competition.
B) Name and describe the three types of symbiosis that interacting organisms display.
12. Using what you know about how energy is transferred through an ecosystem:
A) Describe why there is a stepwise decline of energy as it is transferred up the food chain.
B) Describe why there are more herbivores (lower level consumers) than carnivores (higher level consumers).
C) State which type of consumer is more “expensive” for an ecosystem to support and describe why that is.
D) Describe why certain animals at lower trophic levels can be much larger in size than carnivores.
13. A) The three types of extinction that we discussed were 1) background extinction, 2) mass extinction, and 3)
ecologically extinct. Describe what each type is.
B) State three causes of species loss and briefly describe how they can negatively affect species.
14. Read the online article “Counting the Last Fish” and answer the following questions:
A) Describe two specific reasons, that the article discusses as to, why overfishing has occurred in our oceans.
B) Describe what the term “fishing down the food web” means.
C) Describe two specific approaches, that the article discusses, that can help resolve our overfishing problem.