What is the most plausible explanation for why the male of most bird species have elaborate plumage and mating rituals?

• natural selection

• sexual selection

• gene flow

• genetic drift

Which of the following pertain to movement of plants?

• phototropism

• All choices are correct

• gravitropism

• nasticmovements

• thigmotropism

Isolating mechanisms that prevent reproductive attempts or make it unlikely that reproductive attempts will be successful are referred to as

• pregametic isolating mechanisms.

• postgametic isolating mechanisms

• postzygotic isolating mechanisms

• None of the answer choices are correct

• prezygotic reproductive isolating mechanisms

Linnaeus developed his classification system for organisms according to

• Darwin's theory of evolution.

• LaMarck's theory of evolution

• fixity of species and the sequential ladder of life

• a theory of descent by modification

Which statement is true about prokaryotes?

• They lack ribosomes.

• They usually lack a cell wall

• They contain a nucleus

• They contain a long, linear strand of DNA

• They do not divide by mitosis

How can researchers confirm that phloem moves from a source to a sink?

• They can observe aphids and cut off their beaks.

• They can observe the uptake of ink into the stem of celery.

• They can observe the effects of girdling a tree below the level of the majority of leaves.

• They can use radioactive tracers to measure the flow of sap between two distances over time.

• They can study the cause of maple sap flow in producing syrup.

All of the following statements concerning the evolutionary species concept are true EXCEPT

• an evolutionary “family tree" is used to identify species based on a common ancestor.

• abrupt changes in traits are indicative of the evolution of a new species in the fossil record.

• it relies on identification of certain morphological traits to distinguish one species from another.

• it requires that the members of a species share a distinct evolutionary pathway.

The relationship between the fungi and algae in lichens is best described as

• an endosymbiotic transfer of the chloroplasts of algae to the hyphae cells.

• a possible controlled parasitism wherein the algae are moistened and protected by the fungi, but the fungi do not benefit from the association.

• a possible controlled parasitism wherein the fungi withdraw food from the algae and the algae do not benefit from the association.

• a complete mixing of the genomes of the two groups at the cellular level.

• a simple cooperative mutualism between normally free-living strains.

In the fern life cycle, the _____ generation is dominant

• haploid gametophyte

• diploid gametophyte

• diploid sporophyte

• haploid sporophyte

Pollen grains are formed in _____ and ova are formed in _____.

• receptacles; peduncles

• petals; corolla

• stamens; carpels

• pistil; stamens

• sepals; calyx