# Bio second mid-term exam study guide

Name the major characteristics of chordates?
List the distinguishing characteristics of each of the classes of vertebrates
Draw a simple phylogenetic tree indicating how five classes (major clades] of living vertebrates are related.
What evidence indicates that birds are descendents of dinosaurs?
Describe the circumstances that appear to have led to mammal ascendancy and radiation.
Describe the four embryonic membranes surrounding the embryos of dinosaurs and birds
Draw a simple phylogenetic diagram showing the relationships of five major groups of living amniotes, at
least two should be exclusively endothermic.
Lectures 12-15. Population ecology
Lectures 16-17 on energetics and biogeochemical cycles
Lectures 19-21 on community ecology and biogeography
See the syllabus for the relevant chapters in Campbell and study the lecture notes. Again, you should
understand the terms and the examples used in the text and lectures. Also review the population
problems worked through in Sections. There is not enough time to test your arithmetic problem
solving ability in the Midterm as calculators are not allowed so any numerical problems will be basic.
What equation would you use to project the growth rate of a population of an annual plant like ragweed,
which breeds once and then dies leaving only seeds to overwinter?
A group of 10 freshwater snails invade a new lake where conditions are ideal and predators are absent. The
snails grow and reproduce continuously, multiplying at a rapid rate: r = 0.01 per day. What formula would
you employ to predict how long it will take for the population to triple in size? The numerical solution of
this problem is approximately? Be sure to state the units in which your answer is expressed.
A group of four juvenile snails are introduced to a new lake by a duck with mud on its feet. The lake
provides an idea habitat and the snails grow and reproduce continuously; their intrinsic rate of increase is
0.1 per day. How long will it take for the population to reach 12?
Suppose that the human population in 1984 was 5 billion, and that the birth rate was 32 and the death rate
was 12 (the rates being expressed in conventional units, i.e. per 1000). Making the assumption that the
1984 population will continue to grow exponentially, predict the approximate world population in the year
2014. (Credit requires that you show your work)
At what value of N with respect to K should one obtain the maximum sustainable yield of a harvested fish
or wildlife species?
Complete a labeled diagram showing the human demographic transition as it occurred in the USA since
1800.
Draw a labeled diagram contrasting the survivorship curves of r-selected oysters and K-selected elephants.
What’s logical about logistic growth? Did the human population as a whole grow in accordance with
logistic expectations during the period 1900-1950?
Describe the ecological relationships between lynx and arctic hare.
Why don’t Isle Royale wolves eat all the moose?
Define and give an example of Mullerian mimicry, of Batesian mimicry…
Give an example of a density-dependent factor and a density-independent factor, which may influence birth
or death rates of a population of frogs.
List two life history traits of a K-strategist which distinguish it from an r-strategist.

If you were given a conventional graphical model of a predator-prey interaction showing the two zero
growth curves and involving a refuge for one species would you be able to predict the outcome of their
interaction?
Explain Volterra’s prediction of the outcome of a treatment where an insecticide is applied to a pest species
and its wasp parasitoid.
Write the simple Lotka-Volterra equation for the growth of a predator population in the presence of a prey
population.
What is evolutionarily adaptive about a locust irruption?
What was learned from the Hubbard Brook experiment?

Why is the tropical rainforest approximately 18 times more productive than the tropical open ocean?
Each food chain in a food web is usually only a few links long. What is the most likely reason for this?
Why are fierce animals rare?
Describe two ways a predator can reduce the predator-prey distance.
Consider a marine food web with humpback whales and killer whales as the top predators.
a. what organisms are the primary producers in the grazing food chain?
b. what invertebrate organisms are primary consumers in the grazing food chain?
c. For the first trophic level, is net productivity greater than gross productivity (yes/no/either)?
d. Roughly what ecological efficiency would you expect for the transfer of energy between krill and their
predators
Agricultural land is typically much less productive than the vegetation it replaced. State two factors that
contribute to this observation.
What is a biomass pyramid? an energy pyramid? How do they differ in different communities?
Distinguish between net and gross primary productivity in, for example, the chaparral ecosystem.
Are decomposer food chains more significant than grazing food chains?
Hydrothermal vent tube-dwelling worms can grow 2 m long but have no mouth or digestive tract; how do
they get their energy?
Define and give an example of a keystone species. How might this concept relate to the rivet model of
community composition?
How do most plants obtain most of their nitrogen? Name a symbiotic and a free-living nitrogen fixing
prokaryote.
What is the current concentration of carbon dioxide in the atmosphere and how has that value changed
historically?
Describe a case of biological magnification.
Name four trends that characterize many cases of primary ecological succession.
Can you list two defining characteristics of each of four terrestrial biomes?
Describe two ways in which phytoplankton obtain phosphorus in a deep oligotrophic lake.
Why are carnivorous plants typically found in tropical rainforests or acid bogs?
What is the individualistic hypothesis of community composition?
How does continental drift account for the geographic distribution of marsupials today?
List three important generalizations that can be learned from the study of the Pleistocene species and
biota’s.
What are the current best estimates for global temperature and sea level, relative to today’s, when
atmospheric CO2 doubles? What fraction of the earth’s terrestrial biomes will be affected by the climate
changes?
Using a simple labeled diagram explain the species-area predictions of the equilibrium theory of island
biogeography. How does distance effect these conclusions?
Predict how three species (your choice, real or hypothetical) will respond differently to climatic change
over the next 100 years.
Can you define or give an example of…
synapsid eutherian Gause’s principle
mutualism fundamental niche Holarctic
Gondwanaland metapopulation extirpation
Wallace’s line thermocline aposematic coloration
chaparral notochord monotreme
Answers to the above questions will not be posted but you are encouraged to check any questions you
can’t answer with your TA.
Please also use this study guide in preparing for the cumulative Final Exam on March 19.