Biology Help. 6 questions?
What is genetic drift? The motion of continental plates over time The production of an evolutionarily independent group of organisms A change in allele frequencies caused by random events Why are the large finches now living on the Galápagos Islands different from the original source population from a nearby island? All three answers are correct. Natural selection favored individuals that were more fit in the new environment. The separation of habitats reduced gene flow between the populations. Genetic drift occurred in the two populations. True or false? The last ice age produced many different species mainly because populations dispersed and colonized new habitats.
a. True
b. False Which of the following statements about reinforcement is true? Reinforcement is also called dispersive selection. Reinforcement increases the number of intermediate phenotypes. Reinforcement is a type of natural selection. Reinforcement decreases the morphological difference between two incipient species. A subset of a population of birds leaves its habitat on the mainland and colonizes a nearby island. The birds, after a period of time, become reproductively isolated. The island sinks and the population of birds that lived on the island returns to its original habitat. Which of the following statements about these bird populations is true? The populations will not be able to interbreed because they are different species. The populations were sympatric while they diverged. The populations will be able to interbreed even though they are different species. The birds were separated by a vicariance event. A population of birds colonizes an area in which the insects upon which they feed live inside trees. Which of the following events accounts for an observed increase in average beak size in the bird population over time? Decreased fitness of the insects, allowing the birds to catch them more easily Increased fitness of large-beaked birds, leading to natural selection Increased fitness of the large-beaked birds, creating a new species Decreased fitness of small-beaked birds, creating a new species
