Figure 1 shows some relevant details of a model of how a deoxynucleotide, in this case dTMP, is added to a growing strand of DNA. A D N A template that consists of nine nucleotides is shown. Five nucleotides have already been added to the complementary strand that is growing from left to right along the template. The left end of the growing strand is labeled 5 prime, and the right end is labeled 3 prime. The left end of the template strand is labeled 3 prime, and the right end is labeled 5 prime. An incoming d T T P has three phosphate groups. Arrows indicate that the two outermost phosphate groups split off as the d T M P with the remaining phosphate group is about to join to the 3 prime end of the growing strand. Figure 1. Model showing details of adding a deoxythymidine monophosphate (dTMP) nucleotide to a growing strand of DNA The features of this model provide evidence for which explanation of why all growing strands are synthesized in a 5′ to 3′ direction?

As depicted in the diagram, honeybees communicate the location of flower patches to members of their hives with waggle dances that give information about the direction and distance to the flowers. Which of the following statements about how honeybees communicate the position of flower patches is most consistent with the model?

The tree starts with a branch, from the bottom left to the top right of the tree. Halfway up the branch, it splits into two medium branches. The left medium branch splits to form two smaller branches labeled, from left to right, One and Two. The right medium branch splits to form two smaller branches labeled, from left to right, Three and Four. Based on morphological characteristics, the phylogenetic tree above has been developed for species I, II, III, and IV. DNA sequencing has recently been completed for a particular gene found in all four species. The sequencing will provide additional information for answering which of the following questions?

In Darwinian terms, the fittest individuals of a species are those that

Predation, herbivory, and parasitism are types of ______ interaction.

The ______ species is the species that has either the most individuals or the most combined biomass. In most species this is some type of producer. The ______ species is a species that plays a particularly important role in keeping the community diverse and healthy.

Rhagoletis pomonella is a parasitic fly native to North America that infests fruit trees. The female fly lays her eggs in the fruit. The larvae hatch and burrow through the developing fruit. The next year, the adult flies emerge. Prior to the European colonization of North America, the major host of Rhagoletis was a native species of hawthorn, Crataegus marshallii. The domestic apple tree, Malus domestica, is not native to North America, but was imported by European settlers in the late 1700s and early 1800s. When apple trees were first imported into North America, there was no evidence that Rhagoletis could use them as hosts. Apples set fruit earlier in the season and develop faster, where hawthorns set later and develop more slowly. Recent analysis of Rhagoletis populations has shown that two distinct populations of flies have evolved from the original ancestral population of flies that were parasitic on hawthorns. One population infests only apple trees, and the other infests only hawthorns. The life cycles of both fly populations are coordinated with those of their host trees. The flies of each population apparently can distinguish and select mates with similar host preferences and reject mates from the population specific to the other host tree. There is very little hybridization (only about 5 percent) between the two groups. Initially, which of the following isolating mechanisms is likely to have been the most important in preventing gene flow between the two populations of Rhagoletis?

Researchers studied the diversity of macroscopic invertebrates in different areas of watershed ecosystems. They collected samples from 58 sites along 11 streams in the same geographical area. Their data were classified by stream type and can be found in Figure 1. The stream-type classifications range from the perennial stream type, which always has water, to the intermittent stream type, which is dry for more than nine months during the year. The horizontal axis is labeled Stream Type, and the 4 bars indicated along it are labeled Perennial, Transitional, Seasonal, and Intermittent respectively. An error range is given for each bar. The vertical axis is labeled Simpson’s Diversity Index, and the numbers 0 through 0.45, in increments of 0.05, are indicated. Each bar is described as follows. Note that all values are approximate. Perennial. 0.40, plus or minus 0.02. Transitional. 0.34, plus or minus 0.5. Seasonal. 0.39, plus or minus 0.2. Intermittent. 0.32, plus or minus 0.4. Figure 1. Diversity of macroscopic invertebrates in different stream types. Error bars represent a 95% confidence interval (±two Standard Errors from the mean). Which of the stream types had a statistically lower macroscopic invertebrate species diversity than the seasonal streams?

In a large, isolated population of an insect species, a specific gene locus has one dominant allele (A) and one recessive allele (a). The genotype frequencies of the gene were collected for ten generations, as shown in Table 1. Table 1. Genotypic frequencies over ten generations in an insect species AA Aa aa Generation 1 0.47 0.43 0.10 Generation 5 0.32 0.60 0.08 Generation 10 0.20 0.75 0.05 Which of the following could best account for the change in genotypic frequencies over the ten generations?

What is the most likely reason the carrying capacity of the human population is difficult to estimate?