BIOL 1503: FINAL EXAM QUESTIONS AND ANSWERS A+ GRADED. Buy Quality Materials!
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BIOL 1503: FINAL EXAM QUESTIONS AND ANSWERS A+ GRADED. Buy Quality Materials!
Explain the mechanism for evolutionary change proposed by Darwin and Wallace (i.e., natural selection).
Individuals with heritable characteristics experience competition among each other for finite resources. T...
BIOL 1503: FINAL EXAM QUESTIONS AND
ANSWERS A+ GRADED. Buy Quality Materials!
Explain the mechanism for evolutionary change proposed by Darwin and Wallace
(i.e., natural selection).
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.
Define evolution.
change over time of the genetic composition of a population; descent of modern
organisms with modification from preexisting organisms evolutionary adaptation
Explain the statement "It is the population, not the individual that evolves."
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.
List the five conditions that must be met for a population to remain in Hardy-
Weinberg equilibrium.
1. No mutations from one generation to the next
2. Large population size: describes an infinite population size
3. No gene flow: no migration between the populations
4. No natural selection
5. Random mating: equal mating opportunities
Describe the significance of mutation in the generation of genetic variability.
Changes in nucleotide sequence of DNA are the source of new alleles and genes and is
the ultimate source of variation.
Explain the role of population size in genetic drift.
Genetic drift is the process of change in the genetic composition of a population due to
chance or random events rather than by natural selection, resulting in changes in allele
frequencies over time. If a population is small, there is is less variation between the
organisms. If a catastrophe occurs, the population will not be able to recover as quickly
because the alleles will not be as diverse.
Distinguish among directional, disruptive, and stabilizing selection.
Directional selection: natural selection in which individuals at one end of the phenotypic
range survive or reproduce more successfully than do other individuals
Disruptive selection: natural selection in which individuals on both extremes of a
phenotypic range survive or reproduce more successfully than do other individuals with
intermediate phenotypes
,Stabilizing selection: natural selection in which intermediate phenotypes survive or
reproduce more successfully than do extreme phenotypes
Distinguish between allopatric and sympatric speciation.
Allopatric speciation: gene flow is interrupted or reduced when a population is divided
into two or more geographically isolated sub-populations
Sympatric speciation: speciation takes place in geographically overlapping populations
List the reproductive barriers that may lead to speciation and identify whether
they are a prezygotic or postzygotic barrier. Give examples of each.
Prezygotic:
-Habitat isolation: two species that occupy different habitats within the same area may
encounter each other rarely
i.e. garter snakes
Garter snakes live in the same geographic area, but one species live in water and one
is terrestrial.
-Temporal isolation: species that breed during different times of the day or year cannot
mix their gametes
i.e. skunks
Each species of skunk live in the same geographic area, but mate at different times of
the year.
-Behavioral isolation: courtship rituals that attract mates and other behaviors unique to a
species are effective reproductive barriers
i.e. boobies
Boobies only mate after a courtship display unique to their species.
-Mechanical isolation: mating is attempted, but morphological differences prevent its
successful completion
i.e. snails
The shells of two species of snails have spirals that are in opposite directions that do
not allow them to mate.
-Gametic isolation: sperm of one species may not be able to fertilize the eggs of another
species
i.e. sea urchins
This species releases eggs release sperm and egg into the water to fuse, but each
species gametes have different protein receptors that prevent reproduction.
Postzygotic:
-Reduced hybrid viability: the genes of different parent species may interact in ways that
impair the hybrid's level of development or survival in its environment
i.e. salamanders
Those who hybridize often produce frail offspring.
-Reduced hybrid fertility: even it the hybrids are vigorous, they may be sterile
i.e. mules
When male donkeys and female horses mate, they produce mules, which are a sterile
species.
-Hybrid breakdown: some first generation hybrids are viable and fertile, but when they
mate with one another and the parent species, the next generation are either feeble or
, sterile
i.e. plants
Explain the endosymbiotic theory for the evolution of the eukaryotic cell.
The endosymbiotic theory is a relationship between an anaerobic cell and an aerobic
cell. It is the theory that mitochondrion and plastids, including chloroplasts, originated as
prokaryotic cells engulfed by an ancestral eukaryotic cell. Eventually, the host cell and
the engulfed cells evolved into a single eukaryotic cell. The engulfed cells were possible
undigested prey or internal parasites or mutualists. Scientists hypothesize that a
heterotrophs engulfed the prokaryotic mitochondria and plastids, able to use the
nutrients from photosynthesis from these prokaryotes. However, the world was
becoming increasingly aerobic, so the host cell most likely used the oxygen to its
advantage -- aerobic respiration. These cells would become one organism over time.
The evidence that supports this theory is found with the structure and function of the
chloroplasts and mitochondrion. Each structure has its own DNA (circular DNA), which
is very similar to the structure of today's prokaryotes. The double membrane structure of
each organelle is also very similar to the structure of prokaryotes. In addition,
mitochondria and chloroplasts also have their own ribosomes to make their own
proteins, which are very similar in structure to those found in prokaryotes.
Describe the timing of key events in the evolution of the first prokaryotes through
the evolution of humans.
Explain the hierarchical classification system and list the different levels of the
system.
Hierarchical Classification is the hierarchy of increasing inclusive categories. The major
taxonomic categories from most inclusive to least inclusive is species --> genus -->
family --> order --> class --> phylum --> kingdom --> domain. Ways to remember include
Keep Pipes Clean OF GaS or Kindly Professors Cannot Often Fail Good Students.
List the derived characteristics that distinguish prokaryotes from other life forms.
-Capsule: sticky layer of polysaccharide or protein, may cover the cell wall of many
prokaryotes
-Fimbria: allow prokaryotes to stick to their substrates of other individuals in a colony
-Sex pilus: the filamentous projections (pili) on the surface of a bacterium that are
important in
conjugation
-Nucleoid: an irregularly-shaped region within the cell of prokaryotes which has nuclear
material
without a nuclear membrane and where the genetic material is localized
-Plasmid: small circular DNA rings
-Flagellums: a tail-like projection that protrudes
Distinguish, with prokaryotic examples, among photoautotrophs,
chemoautotrophs, photoheterotrophs, and chemoheterotrophs.
List the derived characteristics of members of the Kingdom Protista that
distinguish them other life forms.
Identify the major groups of land plants based on their derived characteristics.
Kingdom Plantae
-Bryophytes (nonvascular plants)
------>Phylum Hepatophyta (liverworts)
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