Bio 102 Unit Test 1 Flashcards
only quiz answers from SI
Darwin originally defined evolution as
descent with modification
Observation that must be explained in a unifying theory
about life?
Many basic characteristics are shared by all living things.
True statement about Charles Darwin
He proposed natural selection as the mechanism of evolution.
During his voyage around the world, Darwin was inspired to think about evolution by
a. the unique organisms he saw in the Galápagos Islands
b. fossils he collected
c. studying adaptations of organisms to their environments
d. the works of others such as Lamarck
In Darwin’s view of descent with modification,
natural selection can improve the match between an organism and its
environment
The breeding of plants and animals for particular traits by humans is called
artificial selection
The smallest unit that can evolve is a
Population
Which of the following is an example of the process of evolution?
Herbivory
According to the theory of evolution, anatomical and molecular homologies should
produce similar patterns of evolutionary relatedness
How did some strains of Staphylococcus aureus become resistant to antibiotic drugs
Some members of the bacteria population must have had genetic variation
that made them resistant to antibiotics, and these bacteria had greater
reproductive success than sensitive individuals.
Seemingly dissimilar organisms such as hummingbirds, humans, and whales have similar
skeletal structures. This most directly suggested to biologists that
dissimilar organisms might have evolved from a distant, common ancestor
Animals that possess homologous structures probably
evolved from the same ancestor
On an evolutionary tree
homologous characteristics form a nested pattern
c. scientists are sure of the correct placement and relation
Which of the following is an example of convergent evolution?
Dolphins and sharks have a similar streamlined body shape.
Vestigial organs are
remnants of structures that were useful to an organism’s ancestors but that
are now nonfunctional or show reduced function
All known organisms translate genetic information to produce protein molecules via the
same genetic code. This finding strongly supports the hypothesis that
all organisms are descended from a single common ancestor
Evidence from molecular biology supports the theory of evolution by demonstrating that
closely related organisms have more similar DNA and proteins than more
distantly related organisms
What did Darwin observe about species on islands?
They are often closely related to species from the nearest mainland or
neighboring islands.
To describe evolution as a “scientific theory” means that
it is a broad model that is supported by many observations and much
experimental evidence
How do we define evolution?
change in a population’s allele frequencies over generations.
Allele frequencies can be altered b
a. genetic drift
b. gene flow
c. natural selection
Which of the following mechanisms can form entirely new alleles?
Mutation
Sexual recombination includes the shuffling of chromosomes in
____ and fertilization.
meiosis
Which type of mutation plays the most important role in increasing the number of genes
in the gene pool?
Duplication
Which of the following would seem to be an example of neutral variation?
Human fingerprints
What is the importance of neutral variation in evolution?
Neutral variation increases genetic variation, allowing a population to carry
more alleles that may help it respond to environmental change.
In the Hardy-Weinberg equation, p2 represents
The expected frequency of homozygous dominant individuals in the
population
In the equation for Hardy-Weinberg equilibrium, 1 represents
the sum of the frequencies of the genotypes for a particular gene locus
Which of the following sets of conditions is required for Hardy-Weinberg equilibrium?
Random mating, no natural selection, and a large population
An earthquake hits a small island. All but a small group of closely related lizards are
eliminated, and the survivors spread out over the island. This is an instance of
bottleneck effect
Which of the following scenarios would most likely result in the microevolution of a
population of humans?
A colony of humans on the moon is isolated from Earth.
Which of the following is the best example of gene flow?
Wind blows pollen from one population of plants to another and
cross-fertilization occurs.
Which of the following most accurately measures an organism’s fitness?
how many fertile offspring it produces
Antibiotic resistance in bacteria is an example of which of the following?
Directional selection
Stabilizing selection
favors intermediate variants in a population
Which type of selection maintains stable frequencies of two or more phenotypic forms in
a population?
Balancing selection
Selection that acts over evolutionary time to preserve traits that increase an individual’s
ability to mate is known as
sexual selection
A number of mosquito populations today are resistant to insecticides that were once quite
effective. Biologists think that insecticide resistance evolved in mosquitoes because
a few mosquitoes were probably resistant to the insecticide before it was ever
used, and these individuals were more likely to survive and reproduce in the
presence of insecticide
When gene flow between two populations ceases, the potential for
__________
exists.
speciation
At which point in the adaptation of a population is it clear that speciation has occurred?
Gene pool changes establish reproductive barriers between two populations.
Prezygotic barriers
prevent fertilization of gametes from members of closely related species
Which reproductive barrier actually prevents individuals of closely
related species from copulating successfully?
Mechanical isolation
an example of a postzygotic reproductive barrier?
Two fruit flies of different species produce sterile offspring.
Which of the following conditions is necessary for speciation to occur?
Reproductive isolation
evolutionary mechanisms does not contribute to the process of
allopatric speciation?
Gene flow
A new species can arise in a single generation
if a change in chromosome number creates a reproductive barrier
In a hybrid zone, which of the following would tend to lead to reinforcement?
a. Reduced hybrid viability
b. Hybrid breakdown
c. Sexual selection
d. Reduced hybrid fertility
In the case of the Lake Victoria cichlids, sympatric speciation has been shown to be
driven by
sexual selection
How many genes must change in order to form a new species?
There is no set number of genes or loci that produces a new species. Genetic
and environmental factors interact.
The time interval between speciation events is typically
Times between speciation events vary widely and depend on generation
times, causes of speciation, environmental factors, and chance.
The early atmosphere on Earth is thought to have lacked which of the following gases?
Oxygen
Currently scientists think the early atmosphere probably consisted of
N2, H2O, CO2, NH3, CH4, and H2
The Miller and Urey abiotic synthesis experiment (and subsequent, similar experiments)
showed that
simple organic molecules can form spontaneously under conditions like those
thought to prevail early in Earth’s history
Abiotically produced vesicles display which of the following rudimentary qualities
necessary for life?
The ability to perform simple reproduction and metabolism
Many researchers now believe that the first self-replicating molecules were
RNA
Single-celled prokaryotes had Earth to themselves for approximately
1.5 billion years
The correct order of the geologic eras, from most ancient to most recent, is
Paleozoic, Mesozoic, Cenozoic
Ancient cyanobacteria were very important in the history of life because they
produced atmospheric oxygen
What prokaryotic adaptation occurred during the oxygen revolution and opened up the
possibility for energy-demanding multicellular life-forms?
Cellular respiration
What evidence supports the hypothesis that mitochondria and plastids evolved from
prokaryotic endosymbionts?
The first and third responses are correct.
