Download Evolution Unit 1 Free Response Practice

Class Set ~ Please Return
Big Idea 1 - Evolution
Unit 1 Free Response Practice
Single-Part Questions:
1. Scientific evidence from many different disciplines supports models of the origin of life. In a
sentence or two, explain how Stanley Miller’s classic experiment apply mechanism to the
evolution of life?
2. Natural selection acts on phenotypic variations in population. Some phenotypic variation can
significantly increase or decrease fitness of the organisms and the population. List an example
where phenotypic variation increases a population’s fitness, and in a sentence or two, describe
how this variation proved successful.
3. Natural selection is a major mechanism of evolution. The evolution of drug resistant tuberculosis
(TB) illustrates two facets of natural selection. In a sentence or two, identify and explain these two
facets.
4. Mathematical approaches are used to calculate changes in allele frequency, providing evidence
for the occurrence of evolution in a population. If only Mendelian segregation and recombination
of alleles at fertilization are involved, then the gene pool of a population will remain constant from
one generation to the next, as described by the Hardy-Weinberg principle. In a sentence or two,
list the conditions which must be met for a population to remain in Hardy-Weinberg equilibrium.
5. Speciation may occur when two populations become reproductively isolated from each other. In a
sentence or two, differentiate between allopatric and sympatric speciation and give an example of
each.
6. Speciation and extinction have occurred throughout the Earth’s history. Mammals originated 180
million years ago, but did not change much until their adaptive radiation 65 mya. In a sentence or
two, explain this observation.
7. There are several hypotheses about the natural origin of life on Earth, each with supporting
scientific evidence. In a sentence or two, describe the significance of the discovery of protobionts
to our understanding of the origin of life on Earth.
8. Scientific evidence from many different disciplines supports models of the origin of life. Currently,
life is classified into domains: Bacteria, Archaea, and Eukarya. In a sentence or two, provide two
pieces of molecular evidence that justify a common origin for the three domains.
9. Natural selection, genetic drift, and gene flow can all alter the allele frequencies in a population,
but natural selection is the only evolutionary mechanisms that consistently leads to adaptive
evolution, explain why?
Multiple-Part Questions:
1. The theory of evolution is supported by an overwhelming amount of scientific evidence. In The
Origin of Species, Darwin collected a broad range of evidence to support the concept of descent
with modification. In the years since its publication, new discoveries have filled in many of the
gaps that Darwin identified in his book.
a. List the four pieces of evidence Darwin presented in The Origin of Species and describe how
each contributed to our understanding of evolution?
b. The Origin of Species proposed that evolution occurs by natural selection. To support this
mechanism of evolution, Darwin used examples of artificial selection, as well as, observations
he gathered from nature. What were these four observations?
c. Using examples of artificial selection and observations of nature, Darwin drew two inferences
regarding how natural selection occurred and the evolution of a population was possible. What
were these two inferences.
d. If natural selection leads to adaptation, then why do we find examples of organisms that are
less than ideally “engineered” for their lifestyles?
APBioUnit1FreeResponsePracticeII
page 1 of 2
Class Set ~ Please Return
2. Evolution is one of the unifying themes of biology. Evolution involves change in the frequencies of
alleles in a population. For a particular genetic locus in a population, the frequency of the
recessive allele (a) is 0.4 and the frequency of the dominant allele (A) is 0.6.
a. What is the frequency of each genotype (AA, Aa, aa) in this population? What is the frequency
of the dominant phenotype?
b. How can the Hardy-Weinberg principle of genetic equilibrium be used to determine whether
this population is evolving?
c. Identify a particular environmental change and describe how it might alter allelic frequencies in
this population. Explain which condition of the Hardy-Weinberg principle would not be met.
3. Scientists use the concept of homology in identifying evolutionary relationships among organisms.
Features shared by two groups of organisms are said to be homologous if the similarities reflect
shared ancestry. Homology is found in comparisons of structural, molecular, biochemical,
developmental, physiological, and behavioral characteristics of organisms. For each of the
following hypotheses, explain TWO examples of homology that support each hypothesis.
a. Chloroplasts are related to photosynthetic prokaryotes.
b. Spiders and insects are closely related.
c. Echinoderms (sea stars and their relatives) are closely related to the chordates (the phylum
that includes vertebrates).
d. Reptiles and birds are closely related.
e. Humans and chimpanzees are closely related primates.
4. Phylogeny is the evolutionary history of a species.
a. The evolution of a species is dependent on changes in the genome of the species. Identify
TWO mechanisms of genetic change and explain how each affects genetic variation.
b. Based on the data in the table below, draw a phylogenetic tree that reflects the evolutionary
relationships of the organisms based on the differences in their Cytochrome c amino-acid
sequences and explain the relationships of the organisms. Based on the data, identify which
organism is most closely related to the chicken and explain your choice.
c. Describe TWO types of evidence—other than the comparison of proteins—that can be used to
determine the phylogeny of organisms. Discuss one strength of each type of evidence you
described.
Number of Amino Acid Differences In Cytochrome c Among Various Organisms
Horse
Horse
Donkey
Chicken
Penguin
Snake
0
1
11
13
21
0
10
12
20
0
3
18
0
17
Donkey
Chicken
Pinguin
Snake
APBioUnit1FreeResponsePracticeII
0
page 2 of 2