Chapter 3 Flashcards
Natural selection is the consequence of
variation; inheritance; differential reproductive success
The 2000-2004 drought in California
shortened the growing season of the mustard plant; led to earlier flowering in the mustard plant; created selective forces that changed the characteristics of the mustard plant
Researchers studying variations in oldfield mouse coat color found that the light coat color of many beach populations was due to a
mutation in the Mc1R protein, which reduces the ability of alpha-MSH to bind; mutation in the regulatory region of the Agouti gene, which increases ASP expression; reproduction in eumelanin production
Natural selection sorts on
phenotypic, not genotypic, differences in a population
Genes affect traits
by producing a norm of reaction
Natural selection is a process by which
the characteristics of populations change over time
When evolutionary biologist study the process of natural selection, they focus on
how a trait of interest changes of time; how a trait of interest remains constant over time
A species’ life history strategy refers to
a schedule and manner of investment in SURVIVORSHIP over the lifetime of an individual;
a schedule and manner of investment in REPRODUCTION over the lifetime of an individual
The formal definition of “fitness” in evolutionary biology
pertains to relative reproductive success
A trait that serves one purpose today but evolved under different selective conditions is
called an exaptation
The guppy behavior studies presented in your test, including the experiments on transferring guppies between high predation and low predation sites, illustrate the
Rapidity with which natural selection can operate; significant differences in behavior that have evolved between populations over 10,000 years; significant differences in behavior that have evolved within populations due to predation stress
Considering the phylogenetic evidence that feathers evolved prior to flight, what might have been the original function of feathers?
heat retention; facilitating tactile sensation; waterproofing; shielding from sunlight
The antagonistic pleiotropy hypothesis proposes that
the same gene(s) that code for beneficial effects also code for deleterious effects in other contexts
Gene sharing is
one way that a new molecular function can arise; is a form of molecular exaptation
An exaptation is a
trait originally selected for one function but later co-opted for another
How can we explain the exquisite complexity of some complex traits, such as the vertebrae eye?
Each intermediate step toward the evolution of complex traits was itself adaptive; Intermediate stages of complex traits were functional and selected for in the past but were selected for a function other than that observed today
Evolutionary change in one species that affects the selective conditions for a second species is know as
coevolution
The term for a simultaneous action of natural selection on each side of the host-pathogen interaction is known a a(n)
evolutionary arms race
Why aren’t organisms perfectly adapted to their environments?
There are physical constraints that cannot be overcome;
An organism’s surroundings do not present a stationary target to which natural selection can optimize its phenotype; the process of natural selection lacks forsight
The results of the Lenski and Travisano experiment on cells in 12 replicate lines of E. coli illustrate the fact that
Evolution by natural selection is sometimes significantly affected by chance events, such as random mutations, and the order in which they happen; Evolution by NS is often a predictable, repeatable process
According the figure “Droughts and flowering time,” which of the following statements is true? Part 1
Descendant populations of the mustard plant growing after the severe 2000-2004 drought flowered earlier in the season that those from pre-drought populations
According the figure “Droughts and flowering time,” which of the following statements is true (about hybrids)?
Hybrids flowered at intermediate times
According to the figure about plant height and elevation, plants with genotype 1
Grow tall at high and low elevations but are short at medium elevations
In principle, the variations in oldfield mouse coat color illustrated in the figure above could result from
Genetic differences; environmental differences; differences in diet; exposure to sunlight
The experiment on early work on predation, coat color, and fitness in the oldfield mouse demonstrates
a selective advantage to mice with coats that match the color of their environment
According to the figure about “high, medium, low-predation pressure and school size,” which of the following is true? Part 1
Group size increases as predation pressure increases
According to Lenski and Travisano’s E.coli cell line graph, which of the following is true
Average cell volume increased substantially over the first 2000-3000 generations
According to the figure about “high, medium, low-predation pressure and school size,” which of the following is true? Part 2
The percentage of fish found in larger groups increases as predation pressure increases
According to Lenski and Travisano’s E.coli cell line graph, which of the following is true? Part 2
After only 500 generations, natural selection had already increased fitness in the evolving strains; Average fitness INCREASED substantially over the first 2000 to 3000 generations
According to the Norm of Reaction Curves figure, which of the following statements is true?
ALL THE ABOVE:
genotypes don’t code for a fixed leaf size
genotypes don’t code for a fixed leaf area
Genotypes code for a number and area of leaves that depends on the intensity of light to which the given plant is exposed
