Quiz 6 Sex, Speciation

A  In a population with sexual reproduction (with recombination) benefitial alleles will be fixed much quicker.

B  In a population with asexual reproduction there can be no benefitial mutations, so deleterious mutations are fixed.

C  In a population with asexual reproduction (no recombination) benefitial alleles will be fixed much quicker.

A  Since the environment always changes, it is best to increase standing variation and change with it (Red Queen hypothesis).

B  Sexual or asexual reproduction both achieve the same genetic diversity, as variation only depends on mutation rate.

C  No, never change a wining strategy. Recombination can spread deleterious mutations (inbreeding).

A  When good genes are selected for survival.

B  The good genes mechanism is the unfortunate event of losing good genes due to genetic drift.

C  When indicator traits reflect fitness of an individual (healthy color).

A  Yes, but this can only occur in hermaphrodites, due to the Fisherian principle (self-selection).

B  No survival for sexual traits is always directly correlated with selection for survival.

C  Yes, where sexual selection is in conflict with fitness selection, there is a trade off involved.

A  Because sperm is smaller, there is more sperm than ovules and consequently more males in the population.

B  This is only of importance in Angiosperm plants, where the smaller male gametes form pollen for wind pollination.

C  This is anisogamy and optimizes fertilization, because mobility and energy storage are incorporated without canceling each other out.

A  The sex ratio is usually determined by genetic drift, inversely related to gene flow.

B  By adjusting the lifespan of the offspring according to the Fisherian runaway rule.

C  For example through sequencial hermaphroditism, where individuals undergo a sex change.

A  Hybrids have genes from different species and thus always have a higher fitness that the homozygous parents.

B  Hybrids between species do not occur in nature, and can only be created in the lab.

C  Depending on how fully distinct species are, they might not produce hybrids, or the hybrids have reduced fitness or are infertile.

A  When two populations in the same area occupy different niches and evolve to form different species over time.

B  When two populations in two distinct, isolated areas evolve to form different species over time.

C  When two populations in adjacent geographic areas sharing a contact zone evolve into different species over time.

A  A typical hybridization process without clonal interference.

B  Siblings, in an inbreeding scenario.

C  Species, according to the Biological Species Concept.

A  A diverse environment can offer many niches (different islands) for sympatric speciation that leads to many new species.

B  A large gene pool with many species can develop into many more species. One species by itself is unable to pass an evolutionary bottleneck.

C  A founder event where many species arrive into a new place usually focusses evolution by reducing the number of species (evolutionary constraints).