Download evolution COB questions

Stephanie Bobbitt
Evolution COB Questions
Chapter 22
1.
a. catastrophism: boundaries between strata corresponded to the time of a catastrophe (flood,
drought, etc.) that wiped out many species in a particular area; Georges Cuvier had this idea
after examining fossils in strata
b. gradualism: a very slow, continuous process brings change; James Hutton’s explanation of
geologic features that uses modern mechanisms for comparison
c. uniformitarianism: geologic processes are the same now as in the past; Charles Lyell law of use
and disuse: body parts become bigger and stronger when often used, others deteriorate;
Lamarck
2. occurrence of evolution explains life’s unity and diversity and natural selection is the mechanism of
evolution; Darwin’s main ideas: individuals have unequal abilities to survive and reproduce, natural
selection occurs through interactions between the environment and differences between organisms in a
population, natural selection allows a population to better adapt to its environment
3. differential reproduction: organisms with traits that the environment favors will produce more
offspring; increases frequency of favored traits (evolution)
4. Lyell’s book about uniformitarianism helped convince Darwin that like geologic features’ slow
adaptation is similar to that of species; Malthus wrote an essay about human population (human
suffering is a consequence of the human population being able to increase fast than the resources) that
made Darwin recognize the struggle for resistance
5.
6. natural selection must happen through interactions between organisms and environment, so there must
be more than one organism to interact with; evolution is measured as changes in proportions of
variations in a population over lots of time
7.
a. comparative anatomy: forelegs, wings, flippers, and arms are variations that evolved from a
common ancestor – homologous structures; humans will probably have back or knee problems
because knee joint and spine came from 4 legged mammals; vestigial organs: remains of
structures that had function in ancestor, ex: snake has pelvis and leg bones from walking
ancestors
b. comparative embryology: all vertebrate embryos have pharyngeal pouches in throat that develop
into homologous structures with different functions
c. molecular biology: all life uses DNA and RNA, and the genetic code is essentially universal
d. biogeography: distribution of species; species are more closely related to nearby species than to
species that live similarly, but farther away; sugar gliders are marsupials because their ancestors
were, not just because they need to glide; islands have animals similar to those on other nearby
land
e. fossil record: oldest known fossils are of prokaryotes – works with the idea that prokaryotes are
the ancestors of all life, sequence of species is consistent with fossil findings
8. It is hard to examine only hereditary aspects when outside environmental factors can change an animal,
hard to prove that certain traits are actually passed onto next generation
Chapter 23
1.
a. modern synthesis: integrates many discoveries/ideas; theory of evolution that emphasizes
populations are the units of evolution, natural selection is the main mechanism of evolution, and
gradualism is what allows small changes over time to cause big change; all ideas are coherent
with Darwin’s ideas
b. gene pool: total genes in a population, includes all alleles at all gene loci in all individuals; each
allele in the pool has a relative frequency
2.
a. big population size, no migration, no net mutations, random mating, no natural selection
b. Hardy-Weinberg equilibrium: processes of meiosis and random fertilization maintaining the
same allele and genotypic frequencies (like a deck of cards being shuffled, but is still the same
deck)
c. these assumptions will not apply, but good basis for studying population evolution/control
group
3.
a. microevolution: tiny change in gene pool that causes evolution (natural selection)
b. macroevolution: cumulative changes over geologic time that result in biodiversity; speciation
(population has changed so much that it cannot mate with ancestral individuals, a new species)
must occur
4.
a. genetic drift: change in population’s allele frequencies because of chance, gene pool is not
exactly shown through the genetics of the next generation, larger drift when population is
smaller; mechanisms include:
b. bottleneck effect: only a small amount of a population survives a disaster that kills most of that
population – the survivors may not have a gene pool identical to before the disaster, reduces
variability
c. founder effect: some individuals go to an isolated/new habitat to live; this group does not reflect
the genetics of the gene pool of the larger population
5.
a. natural selection: alleles passed to next generation are not proportionate to frequencies of
current generation (some individuals will produce more offspring than others); certain traits
may make an individual more likely to survive and reproduce
b. gene flow: genetic exchange because of migration of fertile organisms or gametes between
populations (ex: wind blows pollen from a population of all white flowers to a population of
different-colored flowers – increases frequency of white allele)
c. mutation: change in organism’s DNA, individually is insignificant, but all mutations at all loci
can be significant
6.
a. polymorphisms: 2+ forms of a discrete character are in a population; ex: ABO blood groups have
4 morphs – type A, type B, type AB, and type O; smaller variations
b. environmental factors: geographic variation: differences in gene pools between populations or
subgroups, clines can change certain traits
c. mutations: changes in nucleotide sequences of DNA that results in new alleles – altered traits;
shorter generation span = more mutations
d. sexual reproduction: shuffles and randomly deals alleles, crossing over can occur
7. cline: graded change in a trait across a geographic axis; changes traits within a population; ex: body size
of some species of birds and mammals increases with increasing latitude (less surface area to volume –
conserve body heat in colder environments)
8. random change is unlikely to improve the genome (similar to blindly firing a gunshot through car hood
will improve engine performance); mutations usually will not affect an organism if the mutation even
survive
9.
a. differential reproduction: organisms with traits that the environment favors will produce more
offspring; increases frequency of favored traits (evolution)
b. relative fitness: contribution of genotype to next generation compared to contribution of
alternative genotypes for the same locus
10.
a. directional selection: common during environmental change or migration; shifts frequency
curve for variations in phenotypic character by favoring rare individuals; ex: size of black bears
increased during glacial periods and decreased during interglacial periods
b. diversifying selection: environment changes to favor individuals on both extremes of phenotypic
range; ex: big and small beaks are favored in finches – intermediate beaks would not crack big
or small seeds
c. stabilizing selection: favors the intermediate variants, reduces variation; ex: common human
birth weight is in the range of 3-4 kg, otherwise they might not survive
11. sexual selection: divided into intrasexual (competition among individuals of one sex for a mate) and
intersexual selection (individuals of one sex are choosy in selecting a mate; mates may have features
that only help in this selection, even if they could sacrifice survival)
12. evolution is limited by historical constraints (structures are designed after ancestral structures),
adaptations are often compromises (hands and flexible limbs of humans are helpful, but are more likely
to sprains, tears, etc.), not all evolution is adaptive (wind does not always blow insects that are best
suited for the new environment), selection can only edit existing variations (only favors fittest
variations, may not be best)
Chapter 24
1. species: a group of organisms that can interbreed successfully
a. prezygotic barriers: impede mating or hinder the ova fertilization; examples: habitat isolation
(two species live in different habitats within the same area, like water vs. land), behavioral
isolation (mate will only respond to certain signals sent by a possible mate that only individuals
of a certain species do, like differences in song), temporal isolation (species that breed during
different times of day, season, year, etc.), mechanical isolation (anatomically incompatible, like
male and female copulatory organs do not fit together), gametic isolation (gametes do not fuse
to make a zygote, like gamete must have certain molecules to adhere to complementary
molecules on other gamete)
b. postzygotic barriers: prevent zygote from developing into fertile adult; examples: reduced hybrid
viability (genetics are incompatible), reduced hybrid fertility (offspring are sterile, like a mule),
hybrid breakdown (offspring are fertile, but offspring of next generation are not)
2. allopatric speciation: speciation occurs in populations that live geographically separate
a. conditions for: geologic processes (ex: mountain range) can form separations between a
population; population is small and isolated, so genetic drift and natural selection cause more
changes
b. conditions against: population is big, separate locations are very similar
3. adaptive radiation: evolution of many diversely adapted species from a common ancestor; species in
one location can move somewhere else and develop into another species and move back to first place or
other place, etc.; island biogeography: species can evolve on separate islands and travel between islands
4. sympatric speciation: opposite of allopatric speciation; speciation occurs in populations with geographic
overlap; less common in animals because polyploidy is less common in animals and very common in
plants, and polyploidy is a main mechanism that allows sympatric speciation to occur
5. punctuated equilibrium: species diverge during times of rapid change followed by periods of no
speciation, not slowly and gradually like in gradualism
6. the eye has evolved from some pigmented cells to a complex camera-type eye – evolution is limited by
ancestral restraints – a new eye cannot be completely rebuilt, it must evolve from a previous eye
7. allometric growth: relative growth rates of different body parts during development that gives a body a
shape
a. mosaic evolution: different features evolve at different rates
8. when a HOX gene mutates/duplicates, the extra set may take on new roles like developing a backbone,
creating a vertebrate (macroevolution)
Chapter 25
1. max extinctions: some change/event in environment causes many of the species to go extinct
a. causes: continents merging, temperature changes, volcanic eruptions, changing amounts of
oxygen present, asteroid or comet collision, etc.
2. systematics: study of biological diversity in an evolutionary context; includes taxonomy (systematics is
more inclusive than taxonomy)
3. monophyletic clade: an ancestral species and all of its descendents
4. polyphyletic clade: no common ancestor
5. molecular clock: timing methods based on some genomic regions evolve at a constant rate
a. uses: measuring absolute time – dating the origin of HIV: calibrate clock by comparing DNA
sequences in HIV gene at different times
Chapter 26
1. was not a lot of oxygen in the atmosphere of early earth because most of the oxygen we have now comes
from photosynthesis and photosynthetic organisms did not appear until later / oxygen came from
photosynthetic organisms (cyanobacteria) when they split water
2. Miller-Urey experiment: simulation of the early earth – warm flask of water with H20, H2, CH4, and
NH3 had sparks discharged into it, condenser cooled atmosphere and water and compounds rained into
water, and after time, solution in flask became murky brown and contained organic compounds that
compose organism proteins
3. RNA is 1st genetic material: RNA can act as genetic material and catalyst (ribozymes); RNA has a variety
of shapes, RNA can make proteins
4. protobionts: aggregates of abiotically produced molecules
a. posses: maintain different internal environment, metabolism, excitability
b. lack: ability to precisely reproduce, refined enzymes