Question

3) Which of the following statements is true or false

a) Character displacement occurs when two species using the same resource overlap in their distributions and become more similar to each other than they are where they don’t overlap.

b) If you wanted to know if an organism which expresses a dominant phenotype is homozygous or heterozygous for a trait (e.g., round pea shape, R_), you could do a “test cross” between the unknown individual (R_) and an individual which expresses the recessive phenotype (e.g., wrinkled pea shape) to correctly determine the genotype for this trait in the unknown individual.

c) Intermediate levels of predation and physical disturbance can prevent competitive exclusion and result in higher diversity in a local biotic community in both ecological and evolutionary time. This has been used to help explain why there are more species in the tropics than at higher latitudes.

d) Some species alter their environment (e.g., through their growth and metabolism) so that they enhance the ability of other species to invade and get established in that habitat. This is an example of “facilitation”, and it can lead to succession of different kinds of species and other long term changes in the biotic community.

e) Some groups of mammals continue to lay external eggs with leathery shells in the present day, as did their Reptilian ancestors.

Answer 1

a) Character displacement occurs when two species using the same resource overlap in their distributions and become more similar to each other than they are where they don’t overlap.

True.

b) If you wanted to know if an organism which expresses a dominant phenotype is homozygous or heterozygous for a trait (e.g., round pea shape, R_), you could do a “test cross” between the unknown individual (R_) and an individual which expresses the recessive phenotype (e.g., wrinkled pea shape) to correctly determine the genotype for this trait in the unknown individual

True

c) Intermediate levels of predation and physical disturbance can prevent competitive exclusion and result in higher diversity in a local biotic community in both ecological and evolutionary time. This has been used to help explain why there are more species in the tropics than at higher latitudes

True

d) Some species alter their environment (e.g., through their growth and metabolism) so that they enhance the ability of other species to invade and get established in that habitat. This is an example of “facilitation”, and it can lead to succession of different kinds of species and other long term changes in the biotic community.

False.

e) Some groups of mammals continue to lay external eggs with leathery shells in the present day, as did their Reptilian ancestors.

True