The scientist has created a closed system for their study. In a closed system, matter (such as water and carbon dioxide in this case) can enter or leave the system, but energy can be exchanged with the surroundings. Since the container is sealed and the scientist is able to control the amounts of water and carbon dioxide being pumped in, it fits the definition of a closed system. An open system would allow matter and energy to flow in and out freely, while an isolated system would not exchange either matter or energy with its surroundings. A semi-isolated system typically has limited exchange of matter and energy, which is not precisely applicable here given the controlled pumping of resources.
A scientist is observing a plant in a sealed container. He keeps the container in a sunny location and pumps water and carbon dioxide into the container in controlled amounts, as shown.
What kind of system has the scientists created for their study?
closed system
semi-isolated system
open system
isolated system
9 answers
The energy pyramid shows some organisms found in an ocean ecosystem.
Which statement correctly describes this energy pyramid?
Energy is destroyed when octopus consume mollusks.
Because elephant seals are top consumers, they store the greatest amount of energy.
More energy is found at the level of the octopus than at the level of the mollusks.
Energy is lost to the environment as heat when mollusks consume phytoplankton.
Which statement correctly describes this energy pyramid?
Energy is destroyed when octopus consume mollusks.
Because elephant seals are top consumers, they store the greatest amount of energy.
More energy is found at the level of the octopus than at the level of the mollusks.
Energy is lost to the environment as heat when mollusks consume phytoplankton.
The statement that correctly describes the energy pyramid is:
Energy is lost to the environment as heat when mollusks consume phytoplankton.
In an energy pyramid, energy is lost at each trophic level, primarily as heat due to metabolic processes. This means that as organisms consume lower trophic levels (like when mollusks consume phytoplankton), not all of the energy from the food is transferred to the consumer; a significant amount is lost as heat.
The other statements have inaccuracies:
- Energy is not destroyed when one organism consumes another; it is transformed and transferred.
- Although top consumers generally have access to energy from lower levels, they do not "store the greatest amount of energy" overall, as energy decreases with each successive level up the pyramid.
- There is generally less energy available at the level of the octopus compared to the level of the mollusks, as energy decreases at each trophic level.
Which of the following correctly explains why many organisms can only exist in an open system?
They cannot generate their own energy.
They cannot generate their own heat.
They require sunlight to produce energy.
They are too large.
They cannot generate their own energy.
They cannot generate their own heat.
They require sunlight to produce energy.
They are too large.
The statement that correctly explains why many organisms can only exist in an open system is:
They require sunlight to produce energy.
Many organisms, particularly photosynthetic ones like plants and some algae, depend on sunlight to produce energy through the process of photosynthesis. An open system allows for the exchange of energy and matter with the environment, which is essential for these organisms to obtain sunlight and the resources they need to survive.
The other options are not accurate explanations for the necessity of an open system for many organisms:
- "They cannot generate their own energy" can apply to heterotrophic organisms that depend on consuming other organisms, but this doesn't inherently require an open system since they still rely on the energy flow from the ecosystem.
- "They cannot generate their own heat" does not explain the open system requirement, as heat production is a normal byproduct of biological processes.
- "They are too large" is not a valid reason for requiring an open system, as size does not inherently dictate whether an organism can exist in an open or closed system.
Ocean-atmosphere exchange has profound implications for the environment and the Earth's climate.
Which of the following describes the ocean to atmosphere exchange?
an open system where matter but not energy is exchanged freely
a closed system where energy but not matter is exchanged freely
a closed system where matter but not energy is exchanged freely
an open system where matter and energy is exchanged freely
Which of the following describes the ocean to atmosphere exchange?
an open system where matter but not energy is exchanged freely
a closed system where energy but not matter is exchanged freely
a closed system where matter but not energy is exchanged freely
an open system where matter and energy is exchanged freely
The correct description of the ocean-atmosphere exchange is:
an open system where matter and energy is exchanged freely.
In this context, an open system allows for the transfer of both matter (such as water vapor, gases like carbon dioxide and oxygen, and aerosols) and energy (in the form of heat and solar radiation) between the ocean and the atmosphere. This exchange is essential for processes like weather formation, climate regulation, and the cycling of nutrients and gases.
The picture shows a wind farm. The mechanical energy of the moving air used to turn the blades of the turbines is greater than the kinetic energy of the electricity that is produced.
Which statement explains why this is true?
All energy from the air is transferred away from the blade.
Some energy is released as heat.
Some energy is destroyed during the energy conversion.
Most energy is converted back to mechanical energy.
Which statement explains why this is true?
All energy from the air is transferred away from the blade.
Some energy is released as heat.
Some energy is destroyed during the energy conversion.
Most energy is converted back to mechanical energy.
The statement that explains why the mechanical energy of the moving air used to turn the blades of the turbines is greater than the kinetic energy of the electricity that is produced is:
Some energy is released as heat.
When energy is converted from one form to another, such as from mechanical energy (the mechanical energy of wind turning the turbine blades) to electrical energy (the electricity produced), not all of the energy is converted into the desired form. Some energy is lost as heat due to friction and inefficiencies in the conversion process (like in the generators and other components). This energy loss means that the total output (in this case, the electrical energy generated) will be less than the initial mechanical energy from the moving air.
The other statements do not accurately reflect the principles of energy conversion:
- "All energy from the air is transferred away from the blade" is not correct because not all energy is lost; some is converted to electricity.
- "Some energy is destroyed during the energy conversion" is misleading since energy cannot be destroyed but can be lost in forms such as heat.
- "Most energy is converted back to mechanical energy" is incorrect as the aim is to convert mechanical energy into electrical energy, not back to mechanical.