Entrance quizes Flashcards
What does secondary contact refer to?
When populations that have been allopatrically isolated re-establish contact with each other
An species that is an alloployploid is said to have arisen…
via the hybridization between members of 2 different species
Which is the type of reproductive isolation that would prevent species fusion between two groups upon secondary contact, because during their period of allopatric isolation, that males and females in each group evolved to mate at different times of the year?
Temporal isolation
What term best describes a group of closely related species recently descended from a common ancestor?
A species cluster
What kind of selection is thought to have contributed to the sympatric speciation of apple host-form and hawthorn host-form of Rhagoletis pomonella?
disruptive selection
Why does the “ring species” example illustrate the limitations of the Biological Species Concept?
Because although the two populations at the Southern end of the Central valley are reproductively isolated, they are not genetically isolated due to genetic exchange via intermediate groups along the ring
Which of the following is NOT an example of a post-zygotic isolating mechanism?
gametic isolation
The biological species concept is based on what central idea?
That individuals belonging to the same species are reproductively compatible
What type of speciation involves the the complete physical separation of groups (e.g. by a wide river)
allopatric speciation
The death of hybrid offspring as embryos or at an early age is a case of
hybrid inviability
Which of the following is NOT something that would result in balancing selection?
When selection favours individuals with traits of one phenotypic extreme
Alleles represent
Different genes
Which factor(s) contribute to the expression of phenotypic variation within populations?
Both environmental & genetic factors contribute to phenotypic variation
What kind of populations are most likely to experience the effects of genetic drift? What tends to happen when a population experiences genetic drift?
Small populations typically experience greater effects of genetic drift, which is associated with a decrease in genetic polymorphisms
When related individuals mate, what is the likely consequence for their offspring?
Offspring are more likely to be homozygous, and are typically of lower fitness than others.
What do the predictions of the the Hardy-Weinberg equilibrium formula represent?
The frequency of genotypes (and phenotypes) in a population that is not evolving
Which is the least likely effect of a mutation if it is expressed phenotypically on an individual’s fitness?
No effect on fitness
What kind of selection is thought to be responsible for the distribution of human baby weights at birth?
Stabilizing selection
What phenomenon does “founder effect” refer to?
When a population is established from a small subset of an original population, it tends to have less genetic variation than what is found their “parent” population’s gene pool.
What kind of variation exists in two or more discrete states, with intermediate forms often being absent?
Qualitative
Which of the following sentences best describes the relationship between Natural Selection and adaptation?
Natural Selection is an process, Adaptation is a outcome.
What do vestigial structures represent?
parts of the body that were once functional in ancestral species, but are no longer functional in their decendents
What is mean when biologists describe an organism as having high “fitness”?
That the organism posesses traits that makes them well suited to their environment, and as a result is more likely to survive and reproduce than others.
Which of the following areas of study did NOT contribute to Darwin’s major insights about the theory of natural selection.
research on DNA replication