1.
Which of the following is the primary source of energy for most ecosystems?
Correct Answer
A. Sunlight
Explanation
Sunlight is the primary source of energy for most ecosystems because it is used by plants in the process of photosynthesis to convert carbon dioxide and water into glucose and oxygen. This glucose serves as the main source of energy for all other organisms in the ecosystem. Without sunlight, plants would not be able to produce food and energy, and the entire food chain would collapse. Fossil fuels, geothermal energy, and wind are not primary sources of energy for ecosystems as they do not directly support the production of food and energy by plants.
2.
Which of the following is an example of an abiotic factor in an ecosystem?
Correct Answer
C. Temperature
Explanation
Temperature is an example of an abiotic factor in an ecosystem because it is a non-living component that influences the living organisms in the ecosystem. Temperature affects the metabolism, growth, and behavior of organisms, and different species have specific temperature ranges within which they can survive and thrive. It plays a crucial role in determining the distribution and abundance of organisms within an ecosystem.
3.
What is the process of converting atmospheric nitrogen into a form usable by plants called?
Correct Answer
B. Nitrogen fixation
Explanation
Nitrogen fixation is the process of converting atmospheric nitrogen into a form that can be utilized by plants. This process is essential for plants to obtain nitrogen, as they are unable to directly use atmospheric nitrogen. Nitrogen-fixing bacteria in the soil play a crucial role in this process by converting atmospheric nitrogen into ammonia or nitrate, which can then be absorbed by plants and used for growth and development.
4.
Which of the following best describes biodiversity?
Correct Answer
D. The variety of species in an ecosystem
Explanation
Biodiversity refers to the variety of species present in an ecosystem. It encompasses the different types of organisms, including plants, animals, and microorganisms, that coexist within a particular habitat. Biodiversity is important for maintaining the balance and functioning of ecosystems, as each species plays a unique role in the overall ecosystem dynamics. It also provides various ecological services such as nutrient cycling, pollination, and pest control. Therefore, the best description of biodiversity is the variety of species in an ecosystem.
5.
What is the term for the gradual change in species composition of a community over time?
Correct Answer
A. Ecological succession
Explanation
Ecological succession refers to the gradual change in species composition of a community over time. It is the process by which an ecosystem goes through a series of predictable and orderly changes, starting from the colonization of pioneer species and leading to the establishment of a stable and mature community. This process is driven by factors such as changes in environmental conditions, competition between species, and interactions with other organisms. Ecological succession plays a crucial role in shaping the structure and function of ecosystems and is essential for the long-term survival and adaptation of species.
6.
Which of the following is a strategy used in ecological restoration?
Correct Answer
C. Species introduction
Explanation
Species introduction is a strategy used in ecological restoration. This involves introducing new species into an ecosystem to restore or enhance its biodiversity and ecological functions. It can be done to reintroduce native species that have been lost or to introduce non-native species that can fill ecological niches and improve ecosystem resilience. Species introduction aims to restore the balance and functionality of ecosystems that have been degraded or disrupted due to human activities or natural events.
7.
Which of the following is an example of a sustainable practice in agriculture?
Correct Answer
B. Crop rotation
Explanation
Crop rotation is an example of a sustainable practice in agriculture because it involves the systematic planting of different crops in a specific sequence over time. This helps to maintain soil fertility, prevent the buildup of pests and diseases, and reduce the need for chemical fertilizers and pesticides. By rotating crops, farmers can improve soil health, conserve water, and promote biodiversity, leading to more sustainable and environmentally friendly agricultural practices.
8.
What is the primary goal of conservation biology?
Correct Answer
D. To preserve genetic diversity in species
Explanation
The primary goal of conservation biology is to preserve genetic diversity in species. This involves protecting and conserving the variety of genes within a species, as it is crucial for their long-term survival and adaptation to changing environments. By preserving genetic diversity, conservation biologists aim to maintain healthy populations, prevent extinction, and ensure the overall stability and resilience of ecosystems.
9.
Which of the following is a common cause of coral reef degradation?
Correct Answer
D. All of the above
Explanation
Coral reef degradation is caused by a combination of factors, including increased water pollution, overfishing, and rising ocean temperatures. Increased water pollution can lead to the accumulation of toxins in the water, which can harm coral reefs. Overfishing disrupts the delicate balance of the reef ecosystem, causing a decline in fish populations and disrupting the food chain. Rising ocean temperatures, often due to climate change, can lead to coral bleaching, where the coral expels the algae living in its tissues, causing it to lose its color and eventually die. All of these factors contribute to coral reef degradation.
10.
What is the term for the process of capturing and storing carbon dioxide to reduce greenhouse gas emissions?
Correct Answer
A. Carbon sequestration
Explanation
Carbon sequestration refers to the process of capturing and storing carbon dioxide to reduce greenhouse gas emissions. This can be done through various methods such as planting trees, implementing carbon capture and storage technologies, or using natural carbon sinks like oceans and forests. By capturing and storing carbon dioxide, the aim is to prevent it from being released into the atmosphere, thus helping to mitigate climate change and reduce the overall carbon footprint.
11.
Which of the following is a keystone species in the Yellowstone National Park ecosystem?
Correct Answer
C. Gray wolf
Explanation
The gray wolf is a keystone species in the Yellowstone National Park ecosystem because it plays a crucial role in maintaining the balance of the ecosystem. They are top predators that regulate the population of herbivores such as elk and deer, which in turn affects the vegetation. By keeping the herbivore population in check, the gray wolf helps prevent overgrazing and allows for the growth of diverse plant species. Additionally, their presence has a cascading effect on other species, influencing the behavior and distribution of other animals in the ecosystem.
12.
What is the main cause of deforestation in the Amazon rainforest?
Correct Answer
B. Agriculture expansion
Explanation
Agriculture expansion is the main cause of deforestation in the Amazon rainforest. As demand for agricultural products such as soybeans, beef, and palm oil increases, more land is cleared in the rainforest to make way for farming and grazing. Large-scale commercial agriculture, as well as small-scale subsistence farming, contribute to this expansion. The clearing of land through slash-and-burn techniques and the use of heavy machinery result in the loss of valuable forest cover, biodiversity, and carbon storage capacity.
13.
Which of the following is a characteristic of a healthy and resilient ecosystem?
Correct Answer
A. High biodiversity
Explanation
High biodiversity is a characteristic of a healthy and resilient ecosystem because it indicates a wide variety of different species living in an area. This diversity ensures that the ecosystem is able to withstand and recover from disturbances, such as natural disasters or human activities. High biodiversity also promotes stability and resilience by providing a range of ecological services, such as pollination, nutrient cycling, and pest control. Additionally, it increases the chances of finding new species that may have unique adaptations or traits that could be beneficial for human use, such as in medicine or agriculture.
14.
What is the primary role of decomposers in an ecosystem?
Correct Answer
C. Break down dead organic matter
Explanation
Decomposers play a crucial role in an ecosystem by breaking down dead organic matter. They break down the complex molecules in dead plants and animals into simpler forms, such as carbon dioxide and nutrients, which can be recycled back into the ecosystem. This process, known as decomposition, helps to release nutrients back into the soil, making them available for other organisms to use. Without decomposers, dead organic matter would accumulate, and the nutrient cycle would be disrupted, negatively impacting the overall health and functioning of the ecosystem.
15.
Which of the following is an example of an invasive species?
Correct Answer
D. Zebra mussel
Explanation
Zebra mussels are an example of an invasive species because they are not native to the ecosystems they invade. They were accidentally introduced to North America in the 1980s and have since spread rapidly, causing significant ecological and economic impacts. Zebra mussels outcompete native species for resources, disrupt food chains, clog water intake pipes, and damage infrastructure. Their ability to reproduce quickly and adapt to various environments makes them highly successful invaders. Blue whales, white-tailed deer, and honeybees, on the other hand, are not considered invasive species as they are native to their respective habitats.
16.
What is the term for the total amount of organic matter produced by plants through photosynthesis in an ecosystem?
Correct Answer
A. Gross primary productivity
Explanation
Gross primary productivity refers to the total amount of organic matter produced by plants through photosynthesis in an ecosystem. It represents the energy that is captured by plants from the sun and converted into organic compounds through photosynthesis. This energy is then available to support the rest of the food chain in the ecosystem. Biomass, on the other hand, refers to the total mass of living organisms in an ecosystem, including plants, animals, and microorganisms. Trophic level refers to the position of an organism in a food chain, while ecosystem efficiency refers to the transfer of energy between trophic levels in an ecosystem.
17.
Which of the following is a major threat to marine ecosystems?
Correct Answer
A. Ocean acidification
Explanation
Ocean acidification is a major threat to marine ecosystems. It occurs when the pH of the ocean decreases due to the absorption of carbon dioxide from the atmosphere. This increase in acidity can have detrimental effects on marine life, including coral bleaching, reduced shell growth in mollusks, and disruption of the food chain. It also impacts the ability of marine organisms to adapt to changing environmental conditions. Therefore, ocean acidification poses a significant threat to the health and biodiversity of marine ecosystems.
18.
Which of the following is a strategy to minimize soil erosion?
Correct Answer
A. Terracing on steep slopes
Explanation
Terracing on steep slopes is a strategy to minimize soil erosion. Terracing involves creating flat or gently sloping platforms on steep slopes, which helps to slow down the flow of water and prevent it from washing away the topsoil. By creating these terraces, the water is able to infiltrate into the soil, reducing runoff and erosion. This technique is commonly used in areas with hilly or mountainous terrain to prevent soil erosion and retain moisture in the soil.
19.
What is the term for the interconnectedness of different species in an ecosystem?
Correct Answer
A. Symbiosis
Explanation
Symbiosis refers to the interconnectedness of different species in an ecosystem. It is a term used to describe the close and long-term interaction between two or more different species, where they rely on each other for survival and reproduction. This interaction can be beneficial, harmful, or neutral for one or both species involved. Symbiosis plays a crucial role in maintaining the balance and functioning of ecosystems by promoting cooperation, resource sharing, and mutual dependence among species.
20.
Which of the following is a common approach to conserving freshwater ecosystems?
Correct Answer
D. Implementing water conservation measures
Explanation
Implementing water conservation measures is a common approach to conserving freshwater ecosystems because it involves reducing water usage and promoting efficient water management practices. By implementing measures such as reducing water waste, promoting water recycling and reuse, and implementing water-saving technologies, the overall demand for freshwater resources can be reduced. This helps to maintain the quantity and quality of water in ecosystems, ensuring the survival of aquatic species and the overall health of freshwater ecosystems.