A population of hummingbirds with a variety of beak sizes finds a new food source in a plant that has a long trumpet flower with nectar at the bottom of the trumpet. Over time, these hummingbirds develop longer beaks. This is an example of
A) directional selection.
B) stabilizing selection.
C) disruptive selection.
D) sexual selection.
E) genetic drift.
A
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Which of the following would most likely result in a bottleneck event, why?
A. A small population of geese migrates and joins a large nesting flock of the same species. This is a bottleneck event because the small population do not bring in any new alleles to the large flock. B. A mutation occurs in an individual poison ivy plant, doubling the number of seeds it produces. This is a bottleneck event because even though the mutation is passed down to the next generations, it does not change the frequency of any other alleles in the population. C. A hurricane blows through a coastal swamp, killing 98% of the snails in a population. This is only a bottleneck event if there is a change in the number of alleles in the population. The 2% of the snails remaining still have the same allele frequencies as the total population. D. A large population of broomsedge grass in a field is determined to be in Hardy-Weinberg equilibrium. This is a population bottleneck event because there is no random mating going on which increases the likelyhood that there will be a decrease in the number of alleles in the population. E. A small population of ducks with red beaks join a large population of ducks that have no red beaks. After 5 generations the number of ducks with red beaks is reaching 50% in the population. This is a bottleneck event because there is a decrease in the number of ducks without red beaks.
Protozoans are eukaryotes and as such will always possess a nucleus, mitochondria, and chloroplasts
Indicate whether this statement is true or false.
The enzyme responsible for converting pyruvate to acetyl CoA is called
A. pyruvate oxidase B. pyruvate dehydrogenase. C. ATP synthase. D. hexokinase E. peptidase.
Three plants that share the same niche have taproots of different length. This is an example of ____
a. character displacement b. the competitive exclusion principle c. resource partitioning d. allopatric speciation e. sympatric speciation