Genetics exam 4 chapter 21
White clover plants produce hydrogen cyanide gas in response to herbivore insects feeding on them, deterring or even killing them. Recently white clover in urban areas was found to lack this mechanism. Its thought that since there are less herbivore insects in urban areas, the plant can save energy and resources by not producing hydrogen cyanide. This would be considered an instance of ______.
microevolution
Female spiders are usually significantly larger than male spiders. This phenomena is called _________.
sexual dimorphism
A species of beetles have different horn shapes. A group of two-pronged horn beetles are in log that floats to a remote island. A population of beetles form on the island and they all have two-pronged horns. What is this an example of?
the founder effect
Opossums can be grey or white, with the grey allele being dominate. If the frequency of the grey allele is 0.6, what frequency do you expect for white opossums?
0.16
The frequency of a genetic disorder caused by a recessive allele is 0.01 in a population. What is the frequency of carriers are in the population?
0.18
In snapdragons, the red and white flower alleles exhibit incomplete dominance. If the frequency of the red alleles is 0.3, what frequency of pink flowers do you expect in the population?
0.42
Which of the following is an example of sexual selection?
Peahens prefer peacocks with large and colorful tails, so those peacocks get to mate more frequently.
Which of the following is an example of behavioral isolation?
Two groups of jumping spider don't mate because of differences in their courtship dances
A population of fish has and variety of body colors and patterns. After an oil spill, only white fish with red stripes remain. What is this an example of?
a genetic bottleneck
In a species of Galapagos finch, thick beaked individuals excel at cracking nuts, while thin beaked individuals excel at picking out grubs from trees. Individuals with intermediate beaks aren't good at either task. This is an example of what?
disruptive selection
When some varieties of rice are crossed, the hybrids are viable, but subsequent generations are smaller and have less fitness. This is an example of what?
hybrid breakdown
A genetic bottleneck 12,000 years ago led to ______ in cheetahs, causing deleterious recessive alleles to become much more common.
inbreeding
SS individuals have normal hemoglobin and are susceptible to malaria. Ss individuals have mostly normal hemoglobin and are resist to malaria. ss individuals have sickle cell anemia. This is an example of _______.
stabilizing selection
