Download Evolution Open Ended Questions: Answer the following

Evolution Open Ended Questions:
Answer the following questions to the best of your ability: Make sure you read
each question carefully and provide answers to all of the parts of the question. Do
not leave any question blank.
Question:
1. The cladogram seen here represents the modern-day classification system which
includes three domains and six kingdoms. Explain how this cladogram represents both the
unity and diversity of life within the domain Eukarya.
Answer Key:
The cladogram illustrates the concept of common ancestor. In this case, the common
ancestor for the four kingdoms within the domain Eukarya would be found at the base of the
vertical line for the kingdomArchaebacteria, domain Archaea. This common ancestor was a
unicellular prokaryote. Some, the blue-green algae or cyanobacteria, were autotrophs;
others were heterotrophs. Prokaryotic cells evolved into eukaryotic cells, scientists believe
by endosymbiosis. This gave rise to the domain Eukarya which contains organisms
composed of one or more eukaryotic cells. The simplest of organisms, in the
kingdom, Protista may be unicellular, colonial, or multicellular. Some are autotrophic; some
are heterotrophic. As we progress through the other kingdoms in the domain, we see an
evolution of complexity. In the kingdom Plantae, organisms are multicellular autotrophs; in
the kingdom Animalia, they are multicellular heterotrophs. To summarize, all organisms in
this kingdom have eukaryotic cells (unity) while their body organization, complexity, and
food getting mechanisms all vary (diversity).
Keywords:
Eukarya, eukaryotic, unicellular, multicellular, autotroph, heterotroph, common ancestor,
prokayotic, ,
The evolution of the peppered moth over the last two hundred years has been studied in
detail. Originally, the vast majority of peppered moths had light coloration. However,
because of widespread pollution during the Industrial Revolution in England, the dark
colored moths became much more common.
2. What specifically caused the shift in phenotype of the moths? Please explain in detail.
Answer Key:
The light colored peppered moths were well camouflaged on the trees which also had
lichens growing on them. When the Industrial Revolution took place, the pollution killed the
lichens and also darkened the tree bark with soot from the pollution. Before the Industrial
Revolution, dark colored peppered moths existed, but were not common because they were
not well camouflaged and were easy targets for predators. After the trees became polluted,
the darker moths were well camouflaged and the light colored moths were not. Since the
light colored moths became more visible, predators were able to find them more easily. This
increased predation caused a decline in the number of light colored moths. The dark colored
moths now had a longer life span and therefore increased reproduction to pass on their
coloration to successive generations.
Keywords:
Industrial revolution, camouflage, pollution, reproduction, bark
3. The illustration shows homologous structures among a human arm, a seal forelimb, a
bird wing, and a bat wing. Explain how the structures are evidence of evolution.
Answer Key:
Each of the examples show similarities in their forelimb structures. The organisms may have
developed differently and independent of one another but developed from a common
ancestor.
Keywords:
ancestor, homologous, evolution
4. How does natural selection provide a mechanism for evolution to occur?
Answer Key:
In order for natural selection to occur, there must be natural genetic variation within
species, which is caused by sexual reproduction. With the exception of identical twins, no
two organisms which undergo sexual reproduction are exactly alike genetically. Some
individuals will have genetic traits that are more suited to live in their particular
environment, and these advantaged individuals will likely live longer and have more
reproductive success than less suited individuals. This means that the advantaged
individuals' genes will be more common in the population. Eventually, over long periods of
time, there will be a genetic shift toward the traits of the advantaged individuals. Traits
exhibited by the disadvantaged individuals will likely disappear or become far less common
after many generations.
Keywords:
genetic variation, sexual reproduction, traits, individuals, advantaged, disadvantaged,
reproduce, survive
5. Chance events that cause allele frequencies to change result in genetic drift. Genetic drift
becomes very important when the population size decreases. One type of genetic drift is
the bottleneck effect. Explain how the bottleneck effect changes the population size and
leads to changes in allele frequencies and evolution.
Theory of Evolution
(BIO.B.3.1.2) New Species
(BIO.B.3.1.3) Mutagenic Variations
Answer Key:
The bottleneck effect occurs when an event or a catastrophe drastically reduces the number
of organisms in a population. The random survivors (the bottleneck) of the catastrophe will
not represent all of the alleles of the original population. The survivors reproduce and their
genetic characteristics will be seen in the offspring while characteristics of the original
population will not be necessarily present. Allele frequencies changed and evolution
occurred.
Keywords:
bottleneck effect, evolution, genetic drift
6. In the early 20th century, scientists began to use radiometric dating to determine the
absolute age of fossils. Before this technology was available, scientists used relative
dating to determine the relative age of fossils. Explain the process of relative dating of
fossils.
Theory of Evolution
(BIO.B.3.2.1) Theory Of Evolution
Answer Key:
Relative dating of fossils involves the Law of Superposition. Fossil age can be placed in
sequential order in which events occurred by examining rock strata. The exact age of the
fossil can not be determined this way.
Keywords:
fossils, relative, dating, superposition, layer, sequence