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Bio Exam 3 Study Guide


A Flash Card Set For My Third Exam In My College Biology 101 Class
  
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    • Fossils in the deepest layers of rock are usually the
 
most primitive in a particular lineage.
  • Darwin’s visit to the Galapagos Islands was the ‘laboratory model’ of his concept of
 
evolution.
  • Darwin’s view was that natural selection acts on the
 
variations found in populations.
  • Adaptations are
 
any traits that make individuals more successful in a particular environment.
  • Unique traits, like the hemoglobin of llamas and camels may show relationship, not
 
unique adaptation to harsh, but different environments.
Populations evolve; individuals...
 
do not.
  • Mutation produces alleles as
 
new genetic variation.
  • Variation can be introduced into populations by
 
migrants, crossing over, and sexual reproduction.
  • Neutral mutations ____ ____ ____ ____ an organism.
 
neither harm nor help
  • Directional selection causes one extreme phenotype
 
to have greater success.
  • Stabilizing selection causes extreme phenotypes
 
to be at a disadvantage.
  • Stabilizing selection produces what in the reproduction of humans and some bird species?
 
an optimum, average birthweight in humans of about 7 pounds and a modal clutch size in some bird species of 6 eggs.
  • In a stable, unchanging environment, selection may be
 
absent or undetectable.
  • Disruptive or diversifying selection favors
 
extreme phenotypes.
  • When males compete for mating opportunities, sexual selection often produces
 
males that are twice as large as females.
  • The HbS allele is more frequent in African populations than in the U.S. because
 
heterozygotes (HbA/HbS) have a reproductive advantage in an environment including malaria.
  • The ‘founder effect’ is produced by
 
introducing a small group onto an island.
  • The ‘bottleneck effect’ occurs when
 
an epidemic drastically reduces the breeding population.
  • ‘Genetic drift’ of allele frequencies is more likely when
 
population numbers shrink.
  • _____ are random, heritable, and potentially useful, but unpredictable by location.
 
Mutations
  • Natural selection does not always favor the big and strong;
 
adaptations must match the environmental requirements.
  • Artificial selection is a strictly _____ endeavor.
 
human
  • The fossil record is incomplete for many reasons;
 
fossilization was/is a rare event.
  • Fossils could include
 
tracks, burrows, teeth, skeletons, or casts.
  • Radioisotope dating of fossils uses
 
the ratio of isotope to daughter product in volcanic rocks.
  • Major changes and trends within and between lineages are described by
 
‘macroevolution.’
  • Life on earth probably originated prior to ___ BYA during the _____ eon.
 
3.5 BYA during the Archean eon.
  • Convergence to a similar body shape by sharks and penguins is caused by
 
similar selection.
  • Wings of bird and butterfly are analogous, not homologous, and show
 
convergence of form.
  • Earlier life forms, such as fossil reptiles, would have ____ primitive limbs than living vertebrates.
 
more
  • Genes for embryonic development are ‘conservative’ (change little) because
 
they act early.
  • Phylogenetic relatedness would not be indicated by mere
 
similarities of ecology.
  • Neutral mutations occur at a constant rate and their accumulation is useful as a
 
‘molecular clock.’
  • Natural selection may never act on mutations which
 
are neutral.
The different ‘kinds’ of organisms are also known as different
 
‘species.’
  • The common quality of all separate species is their ______ ______ from other such kinds.
 
‘reproductive isolation’
  • Members of the same species can, at least potentially, mate and produce
 
fertile progeny.
  • The result of the process of speciation is
 
complete reproductive isolation.
  • Migration or ‘gene flow’ would not promote
 
evolutionary change.
species which use external fertilization are less likely to develop
 
reproductive isolation.
  • Stable gene frequencies (genetic equilibrium) is not an
 
‘isolating mechanism.’
  • Genetic divergence by drift or barriers and accumulated mutations can lead to
 
speciation.
  • Isolating mechanisms happening before fertilization are
 
‘prezygotic.’
  • If the hybrid is inviable, the mechanism is a
 
‘postzygotic’ or acting after the zygote has formed.
  • The usual mode of ‘allopatric speciation’ requires
 
physical separation or geographic isolation.
  • Plants may undergo ‘sympatric speciation’ by forming
 
‘polyploids’ in a population.
  • Divergence from common ancestors (phylogeny) is usually represented by a
 
‘phylogenetic tree.’
  • Phylogeny also refers specifically to the _____ _____ among individuals.
 
‘evolutionary relationships’
  • Evolutionary innovations are acquired during rapid divergences called
 
‘adaptive radiations.’

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