Enviornmental

A scientist added bacteria and a nutrient medium that could support the growth of the bacteria to a sterilized petri dish. No other materials were added. The graph models growth of the bacteria over time.

Which of these most likely explains why the bacterial population stopped growing?

• The bacteria competed for nutrients and died after all the nutrients were consumed.

• The bacteria did not reproduce in the system, and eventually each individual died at the end of its life cycle.

• The bacteria mutated from photosynthetic to carnivorous organisms and consumed one another until all the individuals were dead.

• The bacteria became diseased and were unable to survive in the closed system.

A student’s model of an area near a city depicts many activities that affect the quality of the water in the area.

How does the agricultural activity most likely affect the surface water of the area?

• Excess crop fertilizer is carried by runoff into the river, causing excess growth of water plants.

• Excess crop material accumulates on the riverbanks, slowing the movement of the river water.

• Crops reduce erosion, increasing the amount of soil entering the river.

• Crops absorb pure water from soil, causing the remaining water to contain more salt.

The diagram below shows parts of a cell.

Which organelle stores the information that determines an individual’s blood type?

• Organelle 1

• Organelle 2

• Organelle 3

• Organelle 4

A few years ago the population of male blue moon butterflies on the island of Samoa declined. One hypothesis for the decline of the male butterflies is that a parasite infected the cells of female butterflies. The parasite was passed to offspring through the females’ eggs and killed the male butterfly embryos. At one point during the decline, nearly all the butterflies in the population were females, but after five years the number of males in the population increased significantly.

Which explanation most likely accounts for the increase in the number of male butterflies in the five years after the initial parasite problem?

• Male butterflies in the population that survived were able to prey on the parasites living in the females’ egg cells.

• Female butterflies in the population that survived had a genetic adaptation that allowed them to transform into male butterflies.

• Male butterflies in the population that survived had a gene that made them resistant to the parasite, and they passed the gene on to their offspring.

• Female butterflies in the population that survived were able to protect the male eggs from the parasite and provide extra care for the male offspring.

A partial mountain forest food web is shown.

Which statement does NOT describe a relationship shown in the food web?

• Elk are prey for mountain lions.

• Mice are herbivores that consume grasses and are preyed on by snakes.

• Owls prey on rabbits and frogs.

• Rabbits consume shrubs and are parasites of grasses.

DDT is a pesticide that was once widely used to control agricultural pests and mosquitoes. However, this pesticide caused the eggshells of certain birds, including the brown pelican, to become fragile and thin. The adults would then accidentally crush the eggs while trying to incubate them.

What happened to brown pelican populations as a result of DDT use by humans?

• The populations increased much more slowly.

• The populations decreased as fewer eggs survived long enough to hatch.

• The populations remained stable over time.

• The populations increased as pelicans laid more eggs so that more offspring would survive.

Students in a science class visited four local ecosystems. The students observed the species present in each ecosystem and recorded their observations in the table.

Based on these observations, which ecosystem is likely to be the least sustainable?

• Ecosystem 1, because it has the fewest species

• Ecosystem 2, because it includes both aquatic and terrestrial species

• Ecosystem 3, because it has few predators

• Ecosystem 4, because it supports many animals

Which of the following is most likely to cause a change in the genetic traits in an isolated population of a ground-dwelling lizard species?

• The exposure of an individual lizard in the population to radiation that causes a mutation that is not passed on to its offspring

• An unusually dry summer in the lizard population’s ecosystem

• The introduction of an invasive predator that preys on the brightest-colored individuals in the lizard population

• A fast-moving wildfire that burns the canopy of the trees in the lizard population’s ecosystem

A coastal area that once supported a thriving fishing industry is overfished. The number of species found living in the marine ecosystem decreases.

Which of these activities is most likely to increase the natural biodiversity in the area?

• Building artificial reefs and limiting fishing activity

• Introducing non-native species to fill unoccupied habitats and banning fishing

• Building artificial reefs and increasing fishing activity

• Eliminating non-native species and encouraging fishing for large predatory fish

A partial marine food web is shown.

Which organisms all consume the same producer?

• Crabs, pilchards, blennies

• Euphausiids, sweeps, water fleas

• Tiger sharks, dolphins, octopuses

• Sea urchins, crabs, octopuses