Question 1
(Hint: Look in "Patterns- The family tree")
What is the trait that distinguishes primates, rodents/ rabbits, crocodiles, and dinosaurs/
birds from amphibians and earlier lineages?
The difference is that the formers can lay eggs on land rather than in water. The egg is more
complex because there is no water around, and the embryo development is in the amniotic sac
and the amniotic fluid. These animals are the amniotes. They all evolved from some Devonian
amphibians that tried to return to water to lay eggs. Since Cretaceous era, placental mammals do
not lay eggs anymore because the eggs develop in the female's womb instead, and it still has the
amniotic fluid and the amniotic sac. The egg develops within female womb Instead, it does not
have a shell or yolk, but it contains amniotic sac and the amniotic fluid.
Question 2
Would you expect a bird wing and a butterfly wing to be homologous or analogous
structures? Explain.
Analogous structures, this is because they are characteristic whereby two non-related organisms
evolve a body feature where they have the same use. The Butterfly wings and bird wings are not
inherited from the common ancestor of birds and butterflies because such an ancestor has no
wing. Butterfly wings and bird wings do look superficially similar according to their shaped to
allow them to fly.
Question 3
In your own words, list and define the four mechanisms of evolution.
Natural selection, it is an evolutionary change that leads to individuals with certain traits in a
population to have higher survival chances and reproductive rates than others and hence passes
the inheritable genetic features to their offspring.
Genetic drift; it represents random changes that occur in small gene pools which is due to
sampling errors in the propagation of alleles. Examples of genetic drift are the bottleneck effect
and founder effect. In each of the examples, there is a drastic reduction of individuals in a
population hence leading to distortion of the original allelic frequencies.
Gene flow, it refers to the transfer of genes from the gene pool of one population to another
population. Migration of individuals or gametes into different areas can cause a change in the
allelic frequencies in a population. The introduction of new alleles leads to increase in viability
within a population, and there is a combination of new traits.
Mutations, this are the changes that occur in the DNA sequence that is usually within a gene or a
chromosome of a living organism.
Question 4
(Hint: Look in "Mechanisms- Natural selection")
In your own words, give an example in nature of how natural selection works.
An example of natural selection is where in an ecosystem there are giraffes with long necks and
others short necks. If something occurred and low-lying shrubs decreased or died out the giraffes
with short necks will not have enough food. After a few generations, all the giraffes will have
long necks for their survival.
Question 5
In your own words, describe the difference between microevolution and macroevolution.
Microevolution is the process that involves the change in allele frequency that occurs within a
single population while macroevolution is the change that occurs on a scale that transcends the
boundaries of a single population.
Part B: Multiple choice questions
Question 1
In the following phylogenetic tree, which of the following are in the clade that has a therian
mammal ancestor?
monotremes and eutherians
lepidosaurs and archosaurs
monotremes and marsupials
marsupials and eutherians
Question 2
In the following phylogenetic tree, the unique lineage of archosaurs is represented by:
a red line
a green line
a blue line
a black line
Question 3
In the following phylogenetic tree, which of the following is not a shared derived characteristic
of therian mammals?
pouch
holoblastic cleavage
placentation
viviparity
Question 4
(Hint: look in "Mechanisms- Descent with modification")
In a population of beetles which can be either green or brown in color, the gene (allele)
frequency of green beetles in 2009 was measured to be 36% and increased to 52% in 2010. The
gene (allele) frequency of brown beetles in 2009 was measured to be 64% and decreased to 48%
in 2010.
True of False? This population of beetles is evolving.
True
False
Question 5
Which of the following is the best example of the principle of "fitness"?
a white rabbit living on a forested hill side compared to a brown rabbit living
there.
gorilla males with large testicles consistently producing more offspring than gorilla
males with small testicles
the most dominant chimpanzee male in the group eating more often than less
dominant males
a giraffe having thicker,spottier fur than another giraffe
Question 6
Which of the following statements is TRUE?
mutation are non-random
only germline mutations can affect evolution
natural selection is random
mutation always affect the phenotype to the same
extent
Question 7
Hummingbirds feed on flower nectar and often have a beak whose shape is adapted specifically
to only one flower shape, fitting in no other flower species. As a result, this hummingbird may
only feed on that particular flower and is its only pollinator, creating a mutual dependency
between the two species.
This is an example of _facultative mutualism__________.
(spelling counts; lower case letters only, please).
Question 8
A field biologist discovers a population of pocket mice in Nebraska which has a very different
phenotype of the other populations of pocket mice in the area.
Which of the following is the best strategy the biologist should use in order to establish whether
or not she has found a new species?
compare the color, size, shape, and any other physical traits between the various
populations to the newly discovered one and if they look at least 95% the same,
consider them the same species.
check to see what kind of habitat they live in, and if it is the same, consider them the
same species
check to see what they eat, at what time of the year they breed, how many offspring
they generally produce, and what their social structure is, and if it is the same,
consider them the same species
Check to see if they would produce viable and fertile offspring when brought
together to mate. If yes, then consider them the same species
Question 9
The fact that a mule (hybrid offspring of a horse and a donkey) is sterile is an example of:
reduction of gene flow
genetic drift
reproductive isolation
geographic isolation
Question 10
True or False. The mechanisms causing microevolution are different from those of
macroevolution.
true
false
Reference
Mayr, E. (1982). The growth of biological thought: diversity, evolution, and
inheritance. Harvard University Press.
Avise, J. C. (1994). Molecular Markers, Natural History and Evolution: Natural
History and Evolution. Springer Science Media.
Nicoglou, A. (2015). Phenotypic Plasticity: From Microevolution to
Macroevolution. In Handbook of Evolutionary Thinking in the Sciences (pp. 285318). Springer Netherlands.
Rabosky, D. L. (2013). Diversity-dependence, ecological speciation, and the role of
competition in macroevolution. Annual Review of Ecology, Evolution, and
Systematics, 44, 481-502.