Evolution
Additional questions and directions of further study
Lecture 1
1. Evolution is often seen as a supertheory of biology unifying its branches.
Discuss this point.
2. Is it possible that acquired features can be transmitted to the next generation
and therefore become heritable?
3. Does the principle of uniformitarism generally hold?
4. Discuss whether the principle of population growth of Malthus today holds.
How does Malthus view fit to modern ecological models of population growth
and regulation?
5. Is the static Linnean system compatible with a gradual change in species?
6. Is the scala naturae an early evolutionary model?
7. Search the internet for biographies of Ernst Haeckel, George Gaylord Simpson,
Theodosius Dobzhansky, Ernst Mayr, Bernhard Rensch, Ronald A. Fisher,
Motoo Kimura, Stephen J. Gould, and Richard Dawkins.
Lecture 2
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What does an organism prevent from fossilization?
Where are fossilization conditions worst?
Read about the geological mechanisms of continental drift.
A fossilized bone that was deposited between two basalt layers is assumed to
be several million years old. Which absolute dating method should be used to
confirm this hypothesis?
5. What about marine mollusc shells assumed to be several hundred thousand
years old?
6. How far does dendrochronology reach into the past?
7. What other dating methods exist?
8. Discuss possible pitfalls in the radiometric dating methods.
9. Discuss the distinction between absolute and relative dating.
10. Find further examples for a matching between plate tectonics and phylogeny.
11. How will the distribution of continents look like in 50 mya?
Lecture 3
1. Do phylogenetic trees with many roots exist?
2. Does triple and quadruple branching of phylogenetic trees exist?
3. Recently genetic fingerprinting (species barcoding) became popular in
systematics. List pros and cons of this method.
4. There was a long discussion between cladistic and gradualistic orientated
taxonomists. Discuss both views of phylogeny.
5. Why are lungs not an autapomorphic character of amniotes?
6. Look for other applications of Occam’s razor in Biology.
7. Apart from the Jukes Cantor model the Kimura model is often used to infer
evolutionary distances. What is the key assumption of this model?
8. Does the statement that all phylogenetic trees have a single root hold for
bacterial trees as well?
9. Is it possible that a polyphyletic taxon is the common ancestor of a
phylogenetic tree?
Lecture 4
1. Nanobes are reported to grow in the presence of oxygen. Is this probable for
an early form of life?
2. There are many computer programs designed to mimic life (artificial life). They
are able to change themselves during program run. Discuss whether these
programs can be called life.
3. What are the basic features of hydrothermal smokers?
4. Discuss why three or more sexes never evolved.
5. Discuss the implication of the distinction between genotype and phenotype for
the early evolution.
6. Does Spiegelman’s monster confirm the Eigen equation?
7. The evolution to eukaryotes took more than 2000 mya. The evolution from
eukaryotes to the first metazoan took about 1000 mya. The evolution from the
primitive metazoan to man lasted less than 700 mya. Discuss this accelerating
speed in evolution.
8. Why did eukaryote live evolved only once?
Lecture 5
1. Molecular studies indicate that the radiation of metazoan phyla occurred 800
to 1000 mya ago. On the other hand, the first paleontological records date
back 600 mya. How to explain this discrepancy?
2. Discuss the evidence for and against the Porifera and the Placozoa to be the
most primitive metazoan.
3. Discuss the phylogenetic position of the Ctenophora. Is it possible that they
are most closely related to the Deuterostomia?
4. Compare the Ediacaran and the Cambrian fauna. What caused the changes in
faunal composition?
5. The history of earth saw periods of glaciations that seem to occur at regular
intervals of appr. 250 mya. Discuss the evidence and the possible causes of
such regularities.
6. Molecular evidence puts the radiation of land plants into the Ordovician more
than 50 mya before the first paleontological evidence of land plants. Discuss
this discrepancy.
7. Discuss the function of the temporal cranial openings of anapsid, synapsid and
diapsid amniotes. What about the ears of anapsid reptiles?
8. Are hairs adaptations or exaptations for thermoregulation?
9. Each of the paleontological periods can be subdivided into epochs. For
instance the Permian is subdivided into the Lopingian, Guadalopian, and
Cisuralian epochs. Are these and other epochs timely the same at all
continents? What does this mean for our understanding of geological and
biological processes that form faunal compositions and evolutionary processes?
Lecture 6
1. Discuss the possible causes of the adaptive radiation of the
Archosauromorpha in the Triassic period.
2. In mammals genetic diversification preceded morphological diversification by
about 40 mya. Discuss possible reasons and implications for evolutionary
theory.
3. Terrestrial arthropods never developed larger size and brains. Discuss
possible reasons?
4. A similar problem regards cephalopods, which never entered land.
5. Is it possible to reconstruct a Jurassic Park from ancient DNA?
6. What caused the rise of insects during the Cretaceous and Paleogene?
7. Discuss possible causes of the decline in dinosaur diversity during the late
Cretaceous.
8. Mammals are phylogenetically older than diapsid reptiles and assumed to be
ecologically and intellectually smarter. Why didn’t they radiate during the
Mesozoic era?
9. Evolution had an extraordinary fondness for beetles and Hymenoptera. Why?
10. Marine diversity remained appr. constant since the Cambrian explosion.
Discuss possible reasons.
Lecture 10
1. There has been a long and ongoing discussion about the interpretation of the
fundamental theorem. Search the internet for different opinions about the
meaning of the theorem.
2. Does inbreeding result in lower or higher genetic variability?
3. What are cytoplasmatic genes and how can they cause intragenomic conflicts?
4. An example of the heterosis effect is sickle cell anaemia. Clarify the
mechanism why sickle cell anaemia is very abundant in some African
populations.
5. Does classical population genetics predict high or low levels of polymorphism?
Does the prediction fits to reality?
6. If all phylogenetic trees have single roots, genealogical trees must also have a
single root. What does this mean for the evolution of man?
7. What are evolutionary bottlenecks? Do they influence evolutionary speed?
8. Does the Foley equation predict that every taxonomic lineage necessarily will
go extinct?
9. Neutral theory predicts high levels of polymorphism at higher population sizes.
Bottleneck effects act a very low effective population sizes. Discuss the
evolutionary implications of both mechanisms.
10. Describe analytically the change in gene frequency if the recessive allele is
lethal.
11. Does adaptive evolution proceed more rapidly in larger or in smaller
populations?
Lecture 11
1. Most species have a great variation in reproductive success. Does this
variation promote evolutionary change? How does variation in reproductive
success influence effective population sizes?
2. Is it possible that natural selection decreases mean population fitness?
3. The rise of Lepidoptera was surely triggered by the rise of nectar containing
flower plants during the Cretaceous and Paleogene epochs. However,
Coleoptera, parasitic Hymenoptera, and Diptera are mostly non-pollinating.
Discuss possible causes for their adaptive radiation within the last 100 mya.
4. One method to infer evolutionary trends and constraints is the study of taxon
body size distributions. Many such size distributions are skewed to the right;
that means the number of smaller species exceeds the number of larger
species. Search the internet for examples of body size distributions and
discuss possible mechanisms for skewed distributions.
5. The phrase adaptation is used for heritable phenotypic traits. What about
behavioural adaptations? If they are learned we might speak of cultural
adaptations? What do you think about such a terminology?
6. Van Valen’s rule told that lineages have to evolve permanently just to survive.
What does this mean for the herbivore – plant interactions? Who won this
evolutionary arms race?
7. Herbivores of trees have much shorter generation times than their hosts?
Does this mean that trees are always the losers in the host – parasite
coevolutionary race?
8. Plant herbivore and parasite – host coevolution can be modelled using the
Lotka - Volterra equations for competitive interactions and using predator prey models. What does this mean for the change of gene frequencies of
parasites ad hosts in time?
Lecture 12
1. Looking at the various species concepts. Do you think ‘the species’ is a useful
concept in evolutionary studies?
2. Discuss possible causes for the high biodiversity of East African freshwater
fish diversities.
3. “Species” are often genetically not isolated. What does this mean for effective
population sizes? Is cross species gene transfer common?
4. Discuss the theory of punctuated equilibrium in terms of adaptive landscapes.
5. Discus possible genetic mechanisms that result in a saltational mode of
evolution.
6. Discuss the major evolutionary trends and constraints presented in the lecture.
7. Looking at the distribution of mass extinction through time it seems that they
occurred at more or less regularly time intervals. Think of a test to infer
whether this is true.
8. Mass extinctions are often followed by higher rates of speciation and radiation
of formerly recedent lineages. What factors might trigger such a pattern?
9. There has been a controversy around the question whether sympatric
speciation occurs. Discuss pros and cons.
10. Does premating isolation occur before or after postmating isolation? What
does this mean for speciation times?
11. Does evolution need hopeful monsters?
12. The background extinction rate of marine taxa declined over time. However
total marine biodiversity seems to be stable since Cambrian. Discuss the
implications for mean speciation rates. Think of possible mechanism that
caused both trends.
Lecture 13
1. What does the fact that species and higher taxonomic levels are not units of
evolution tell about the reality of these taxonomic entities?
2. Richard Dawkins proposed the meme as the unit of cultural evolution. Discuss
the pros and cons of this concept.
3. Stephen J. Gould wrote that sociobiologists were telling ‘just so stories’.
Discuss how to decide whether behavioural traits in man are adaptive or
transmitted by culture and learning.
4. Analyze the retaliator and the bourgeois game in more detail and infer the
ESS.
5. Search the internet for more information about selective infanticide and sex
ratios in man.
6. Termites are not haplo-diploid. Nevertheless all species are eusocial. Discuss
possible pathways to eusociality in termites.
7. Look for examples of social behaviours in arthropods and lower vertebrates.
Are there social molluscs?
8. What does Nasonia vitripennis need to adjust her sex ratio to the local
situation?