Natural Selection
How might gene flow influence adaptability and survival potential among geographically isolated subpopulations experiencing different environmental pressures?
By promoting outbreeding depression due to incompatible gene combinations from different environments
Through continuous backcrossing, it maintains high levels of fitness by eliminating deleterious alleles from all populations
By strictly conserving locally adapted genes, it ensures homogeneity and consistent adaptation strategies across all subpopulations
It can introduce new alleles that may enhance adaptability under changing conditions or create maladaptive effects depending on compatibility with local adaptations
What would be an expected outcome if a lethal recessive allele persists at low frequencies within a large sexually reproducing population?
The recessive lethal alleles would quickly disappear as individuals carrying them die before reproduction.
Natural selection acts against carriers of this lethal recessive gene reducing its presence each generation until it disappears completely.
The allele hides in heterozygous carriers who do not express the lethal phenotype but can pass the allele onto offspring.
All members of future generations would eventually become homozygous for this lethal recessive allele due to genetic drift.
In an island bird population, which scenario best illustrates how gene flow can impact variation within that population?
Emigrating birds remove common alleles from the gene pool without changing allele frequencies significantly or altering overall variation markedly.
A stable migratory pattern maintains existing allele frequencies by consistently introducing and removing similar alleles each season without significant change over time.
Predators on the island preferentially hunting immigrant birds thereby reducing their numbers and maintaining original allelic proportions intact through selective pressures rather than gene flow effects.
Immigrating birds interbreeding with locals introduce new alleles into the gene pool, thus increasing genetic variation.
Which adaptation would provide an evolutionary advantage for aquatic animals living in cold environments?
Antifreeze proteins preventing ice crystal formation inside cells.
Expanded gill surfaces despite increased risk of freezing.
Large fat reserves leading primarily to buoyancy rather than insulation.
Enhanced visual acuity not connected specifically to temperature regulation.
Which situation best demonstrates the bottleneck effect leading to decreased genetic variability in a population?
A new predator preys on only the smallest squirrels, causing larger squirrels' allele frequencies to increase over time.
A natural disaster drastically reduces the size of an elephant population, leaving only those who happened to be in protected areas.
Migration introduces new rabbit genotypes into an existing gene pool, increasing overall allele variety within that habitat.
Disease targets all frogs equally regardless of their genes, slowly diminishing the population size but not its genetic diversity.
In a food web, which trophic level directly obtains energy from producers?
Decomposers
Tertiary consumers
Primary consumers
Secondary consumers
If a population's allele frequency changes due to gene flow from neighboring populations rather than mutation, what is the likely impact on genetic diversity?
It increases because new alleles are introduced from other populations.
It depends solely on natural selection acting on the introduced alleles' fitness benefits or drawbacks.
It remains constant as gene flow does not affect allele frequencies significantly.
It decreases because gene flow equalizes allele frequencies among populations.

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Which one of these is a postzygotic barrier?
mechanical isolation
temporal isolation
hybrid breakdown
gamete isolation
In a hypothetical population of lizards, which factor would most likely contribute to an increase in variation within the population after a series of wildfires followed by a rapid regrowth of vegetation?
Uniform reduction in predator populations affecting all lizards equally.
The emergence of new microhabitats creating different selection pressures.
Increased sunlight penetration uniformly benefiting all surviving lizards.
A temporary decrease in insect prey leading to uniform starvation rates.
Which type of interaction occurs when two different species benefit from each other?
Predation
Competition
Parasitism
Mutualism