Test 4 Practice Quiz #3

Look at the provided graph showing the distribution of a specific mineral (represented as 'M') in various parts of a crop plant over different growth stages and months. Which of the following statements is true? (Note: The graph shows the parts of a plant such as stems, flowers, and fruit.)

• The stems contain more of mineral 'M' than the flowers throughout the growth period.

• The concentration of mineral 'M' is highest in the fruit during Jube to July.

• Mineral 'M' accumulation in the plant is at its peak during the early stages of vegetative growth.

In a forest ecosystem food web, the primary producers are oak trees, shown at the base of the diagram. Each arrow in the diagram indicates the flow of energy up the web. This diagram does not, however, depict all the energy in the food web. Which of the following modifications to the arrows would be MOST appropriate to include?

• No modification is necessary because the arrows accurately depict the complete energy flow in the ecosystem.

• Introduce arrows from each animal to its surroundings to indicate the energy dissipated as heat.

• Introduce arrows from the soil to the trees and from the air to the birds to indicate how these organisms utilize abiotic factors.

• Insert arrows that loop back from the predators to the prey, such as from owls to mice, to represent a cyclical energy exchange.

This marine food web represents a coastal reef ecosystem covering 15.2 km². The biomass of the producers, which consists mainly of algae, is evenly spread throughout the ecosystem and amounts to 2,200 kg/km².

A new marine conservation plan will protect 40% of the reef from fishing and other human activities, increasing the biomass of producers by 25% in the protected areas. Which of the following is the most likely result after the implementation of the conservation plan?

• The biomass of top predators like sharks will decrease due to improved health of the ecosystem.

• There will be a significant increase in herbivorous fish populations and a moderate increase in medium-sized carnivorous fish.

• The biomass of herbivorous fish will be 8 kg/km², and the biomass of sharks will be 0.8 kg/km².

• The remaining predators will experience a dietary shift and compete more directly with medium-sized carnivores.

The illustration below depicts a pyramid of biomass for a coral reef ecosystem. The shape of the pyramid helps to demonstrate which relationship among the trophic levels?

• Top-level predators in this ecosystem possess the highest amount of living organic matter.

• All trophic levels in this ecosystem contain an equal amount of living organic matter.

• As you go up each trophic level in this ecosystem, the amount of living organic matter decreases.

• There is an increase in the amount of living organic matter with each step up to a higher trophic level in this ecosystem.

You have been assigned a field study role that involves cataloging the variety of life forms in a 10 kilometer region of a tropical rainforest. Your organization intends to collect extensive biological data, documenting the plant life, wildlife, microbial life, and all forms of interaction among them, to evaluate the impact of establishing a conservation area. Given that your task is to observe and note the diversity and interactions of life forms within this ecosystem, your position is best described as:

• an environmental surveyor.

• a biodiversity recorder.

• an ecosystem biologist.

• a community ecologist.

In ecological studies, models such as food chains are used to represent the one-way flow of energy from the sun through different organisms. In contrast, nutrient cycle diagrams are used to illustrate the recycling of matter within an ecosystem.

Which statement characterizes nutrient cycle diagrams, but NOT food chains?

• The cycles depict the necessity of continuous solar energy input to compensate for energy dissipation as heat.

• The cycles indicate the transformation of energy from producers to various levels of consumers.

• The cycles illustrate a closed loop system where elements like carbon and nitrogen are reused.

• The cycles demonstrate a linear progression from producers to apex predators.

An invasive plant pathogen has been introduced into the local ecosystem, which has led to the widespread die-off of terrestrial plant life. Given the interdependent relationships illustrated in this food web, what is the most direct and likely consequence for the animal populations within this nature preserve? All answers can be argued as potentially correct, but which answer is most certain?

• As grass is a fundamental food source for the muskrat, a decline in grass will likely lead to a decreased muskrat population, which may in turn result in a scarcity of prey for the bobcat, potentially diminishing its numbers.

• The alligator, primarily a carnivorous species, may not be directly affected by the loss of plant biomass, as their diet does not consist of plants. However, indirect effects may emerge if prey species populations change due to alterations in the ecosystem.

• If the plant die-off leads to deteriorated water quality or reduced aquatic plant life, the shrimp population may decline, affecting the catfish that feed on them, leading to a potential decrease in catfish numbers.

• Raccoons are adaptable feeders with a varied diet. If plant-based food resources dwindle, raccoons may adjust their feeding habits to include more aquatic organisms such as fish.
  

Consider the carbon in a tree in a forest. How is this carbon most likely returned to the atmosphere?

• The tree absorbs more carbon dioxide through its leaves.

• The tree consumes carbon-rich nutrients from the soil.

• Carbon is released through the process of decomposition when the tree dies

• Some of the carbon dioxide is released when the mitochondria performed cellular respiration within the cells of the tree.

• The tree converts carbon into oxygen during daytime

In coral reefs, clownfish and sea anemones are often found living together. The sea anemones provide protection for the clownfish with their stinging tentacles, which deter predators. How does this example illustrate mutualism?

• The clownfish clean the sea anemone and provide it with nutrients from their waste, benefiting both parties.

• The clownfish are unaffected by the presence of the sea anemone and neither benefit nor suffer.

• The clownfish are harmed by the sea anemone's stinging cells, which make their living space inhospitable.

• The clownfish and the sea anemone compete for food, leading to a strained relationship.

In sustainable farming practices, the use of compost and green manure is common to enhance soil quality. In contrast, some farmers opt for cover crops like rye or oats during the off-season to improve soil health. Both compost/green manure and cover cropping strategies are primarily aimed at boosting the levels of which essential soil nutrient?

• Nitrogen

• Phosphorus

• Potassium

• Magnesium