BIOL 1503 Exam 1 questions
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Evolution - CORRECT ANSWER>>>>change over time of the genetic composition of a
population; descent of modern organisms with modification from preexisting organisms
evolutionary adaptation
Evolution states that organisms descended from ____________ organisms. -
CORRECT ANSWER>>>>ancestral
Adaptation - CORRECT ANSWER>>>>accumulation of inherited characteristics that
enhance organisms ability to survive in specific environment
Favorable Adaptation - CORRECT ANSWER>>>>adaptations that help the organism
survive and reproduce
Catastrophism - CORRECT ANSWER>>>>the principle that events in the past occurred
suddenly and were caused by different mechanisms than those operating today
Describe the evidence that supports catastrophism. - CORRECT ANSWER>>>>Each
strata (layer of rock) represents some sort of catastrophe that destroyed many of the
species living at the time. Catastrophism is confined to local regions which were later
repopulated by new species.
Uniformtarianism - CORRECT ANSWER>>>>the principle that mechanisms of change
are constant over time
What do scientists who support uniformtarianism believe? - CORRECT
ANSWER>>>>The scientists believe that the same geological processes are operating
today as in the past and at the same rate.
Explain the mechanism for evolutionary change proposed by Jean Baptiste de Lamarck.
- CORRECT ANSWER>>>>1. Use and Disuse: bodies of living organisms are modified
through the use or disuse of parts
i.e. Giraffes:
Back in the day, scientists figured out that giraffes had shorter necks and legs. The
giraffes would stretch their legs and necks. The giraffes became longer and taller, and
passed the trait to the next generation
Inheritance of acquired characteristics: these modifications are inherited by offspring;
organisms have the innate desire to become more complex
,Natural Selection - CORRECT ANSWER>>>>the unequal survival and reproduction of
organism due to environmental forces, resulting in the preservation of favorable
adaptations
What are the requirements for natural selection to occur? - CORRECT ANSWER>>>>1.
Variability: variation in traits in a population
2. Heritability: traits have to be inheritable - passed from one generation to the next
3. Differential reproductive success: traits must allow the population to survive and
reproduce better - favorable traits
True or False: Natural selection "selects" from what is available in the gene pool. -
CORRECT ANSWER>>>>True
Explain why new characteristics are not created on demand. - CORRECT
ANSWER>>>>Natural selection only works on the variability already in the population.
The favorable traits are the ones that survive more and reproduce more and have a
disproportionate effect on the next generation.
Explain the mechanisms behind natural selection. - CORRECT
ANSWER>>>>Individuals with heritable characteristics experience competition among
each other for finite resources. These facts result in those individuals who are more
suited for their environment produce more offspring than those who are not well-suited,
and, over time, these favorable traits increase in frequency within the population.
How does natural selection explain the unity of life? - CORRECT
ANSWER>>>>Organisms share many characteristics, indicating that a common
ancestor lived in the remote past.
How does natural selection explain the diversity of life? - CORRECT ANSWER>>>>It is
hypothesized that the ancestral organisms lived in various habitats, so they
accumulated adaptations that fit them to certain ways of life.
Describe the two inferences Darwin made from his observations that led him to propose
natural selection as a mechanism for evolutionary change. - CORRECT
ANSWER>>>>1. Individuals whose inherited traits give them a higher probability of
surviving and reproducing in a given environment tend to leave more offspring than
other individuals.
2. This unequal ability of individuals to survive and reproduce will lead to the
accumulation of favorable traits in the population over generations.
The widespread use of DDT in the mid-1900's put pressure on insect populations to
evolve resistance to the insecticide. As a result, large populations of insects today are
resistant to DDT.
A. Darwinian
B. Lamarckian - CORRECT ANSWER>>>>B. Lamarckian
, Many bacterial strains that infect humans today are resistant to a wide range of
antibiotics. These resistant strains were not so numerous or common prior to the use of
antibiotics. These strains must have appeared or evolved in response to the use of
antibiotics.
A. Lamarckian
B. Darwinian - CORRECT ANSWER>>>>A. Lamarckian
Distinguish between artificial selection and natural selection. - CORRECT
ANSWER>>>>artificial selection: the selective breeding of domesticated plaints and
animals to encourage the occurrence of desirable traits -- purposefully done by human
intervention
natural selection: a process in which individuals that have certain inherited traits tend to
survive and reproduce at higher rates than other individuals because of those traits --
occurs naturally in nature
Explain why an individual organism cannot evolve. - CORRECT
ANSWER>>>>Evolutionary processes acts on individuals, but populations evolve. The
effect of evolution is seen and measured in populations - it is a change in gene
frequency over time through the generations.
Describe the observations of soapberry bugs that supported Carroll and Boyd's
hypothesis that changes in a population's food source can result in evolution by natural
selection. - CORRECT ANSWER>>>>The soapberry bugs in Florida's natural food
source were bloom vine plants (puffy plants). The soapberry bugs would use their beaks
to suck the nutrients out of the seeds. Another species of plant was introduced, and it
was much more compact (the seeds were closer to the surface). Since it doesn't require
as long as a beak length to feed on the plant, we see a decrease in the length of the
beak. Those who fed more effectively tended to reproduce more.
Explain how drug resistance develops in bacteria and viruses. - CORRECT
ANSWER>>>>i.e. HIV Virus
Patients at time zero have a low percentage of resistance to the 3TC. After the drug is
administered, we change the selective pressure, and those who were not resistant to
the drug die off and those who were resistant reproduce and become more plentiful.
Over time, resistance goes up to nearly 100% resistance to 3TC, making the drug
ineffective.
How do we get around this problem?
Drug cocktails: we take three to four different drugs, affecting the bacteria in different
ways.
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