Biology Unit 6 Practice Test

John is completing an internship in biology at the Clearwater Marine Aquarium. While interning there, he monitors an outdoor phytoplankton exhibit to observe how populations of phytoplankton change when exposed to light. It is observed that each year the phytoplankton population within the exhibit increased by 3,000 organisms when it was exposed to high amounts of sunlight. A new high rise apartment complex that overlooks the beach is being built. The new apartment complex will stand between the marine aquarium and the sun. The phytoplankton that were receiving 8-12 hours of sunlight each day will now have between 2-5 hours of sunlight. Which of the following statements is most likely to occur as a result of the new apartment complex?

• A. The population will decline over time.

• B. The population will decrease their need for food.

• C. The population will migrate to another body of water.

• D. The population will choose to evolve new adaptation

The island of Surtsey was formed by a volcanic eruption and first appeared in 1963. Figure 1 contains descriptions of changes in the population and diversity of species that occurred on this island over time. Using Figure 1, which of the sequences below lists the descriptions of changes in the correct order of ecological succession?

• A. I, II, IV, III

• B. III, I, II, IV

• C. II, IV, I, III

• D. IV, III, I, II

There are two species of squirrel in the United Kingdom: red squirrels and gray squirrels. Red squirrels are native to the United Kingdom while gray squirrels were introduced to the United Kingdom from North America in 1876. Figure 1 show the distributions of the two squirrel species in 1945 and 2010.

What statement below explains why there were changes in the UK squirrel populations over time?

• A. The grey squirrel has increased their rate of emigration to the UK.

• B. The carrying capacity for all squirrels in the UK increased over time.

• C. The limiting factors needed by red squirrels are more accessible in 2010 than in 1945.

• D. The grey squirrel's immigration has decreased the available resources for the red squirrel.

Which of the following can most likely be concluded about how invasive species survive and thrive in new environments?

• A. They increase risk of predation.

• B. They increase threat of disease.

• C. They have the ability to travel short distances.

• D. The have the ability to outcompete native species.

The deepest parts of the ocean have much different food chains than most shallow ocean or terrestrial ecosystems. Since there are no plants in these areas, chemoautotrophs usually function as producers in these ecosystems. Chemoautotrophs are organisms that make their own food using the chemicals found around them. Which statement describes why chemoautotrophs are needed to fill this role in these environments?

• A. Sunlight cannot reach the ocean bottom so plants are unable to grow.

• B. Without pollinators, it is impossible for plants to reproduce at greater ocean depths.

• C. Chemoautotrophs have eaten all the plants in this ecosystem.

• D. Plants are unable to survive in salt water.

A group of students in Ms.Griffin’s class are analyzing the changes in a forest community, provided in the graph. Based on the information presented what can the students conclude about what is causing the changes in this forest community?

• A. primary succession after a flood

• B. secondary succession after a volcanic eruption

• C. secondary succession after a fire

• D. primary succession after a mudslide

On the Pacific coast, sea otters are considered to be a keystone species meaning their role in the environment has a greater influence than other species within the same ecosystem. As predators, sea otters are critical to maintaining the balance of the near-shore kelp ecosystems. Without sea otters, kelp forests would disappear off the coast leading to less shelter and food for many other marine animals. Ecologists decided to study the food distribution of organisms with kelp ecosystems. They used the data collected to form the food web illustrated below. According to the food web illustrated, if there was a reduction in the sea otter population which of the following would most likely occur in this Pacific coast ecosystem?

A. A decreased number of sea urchins. B. An increased growth of the nearby kelp forests. C. A decrease in the biodiversity of the ecosystem. D. An increase in the biodiversity of the ecosystem.

• A. An increased growth of the nearby kelp forests.

• B. A decreased number of sea urchins.

• C. An increase in the biodiversity of the ecosystem.

• D. A decrease in the biodiversity of the ecosystem.

Which of the following most accurately explains the difference between primary and secondary succession?

• Primary succession is the sequence of plants that colonize a new area, while secondary succession is the sequence of animals that move in later.

• Primary succession is the sequence of species that become established early in a newly colonized area, and secondary succession is the sequence of species that move later.

• Primary succession is the establishment of a community in an area with no soil, while secondary succession is the establishment of a new community in an existing ecosystem that was disturbed.

• Primary succession is the establishment of a new community in an existing ecosystem that was disturbed, while secondary succession is the establishment of a community in an area with no soil.

The image below shows the impact on Florida coasts based on the amount of sea level rise resulting from Earth's changing climate. What long term effects would a rising sea level have on Florida's coastal ecosystems?

• A. They will stabilize coastal habitats by providing increased access to limiting factors like water.

• B. They will lead to secondary succession and a reduction in the biodiversity to the coastal regions of Florida.

• C. They will increase availability of water causing biodiversity to rise as new species evolve.

• D. They will increase the costal habitat available by making it easier for organisms to access necessary resources.

Introduced species can be a major threat to our environment because they can change an entire habitat, damage human enterprise, and cost the economy millions of dollars. Which of the following is considered the greatest threat to biodiversity?

• Disease

• Over harvest

• Invasive species

• Pollution