Energy In Ecosystems Pretests

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Energy must be transformed in ecosystems because _______.

D. all of the above ——————————————————————————– The above… a. energy cannot be created or destroyed b. an organism’s energy must go somewhere c. an organism’s energy must come from somewhere

Most energy enters ecosystems in the form of sunlight.

True

Heterotrophs convert solar energy into chemical energy.

False

Energy in most ecosystems must flow through autotrophs because ______.

only autotrophs can convert solar energy into chemical energy

How is energy associated with food stored?

potential energy in chemical form

The energy in fossil fuels is derived from the energy stored in plant and animal matter.

True

Which of the following is true about the efficiency of energy transfer in an ecosystem?

The less energy the organism requires, the more efficient the energy transfer.

Lightning strikes are dangerous _______.

D. all of the above ——————————————————————————– The above… a. if a person is in the path of the lightning discharge b. if a person is not in the path of the lightning discharge c. up to 10 miles away from the rain area in a thunderstorm

Primary producers generally form the smallest trophic level of a pyramid of energy.

False

Which of the following best describes the solar radiation absorbed by and radiated from earth?

Most incoming solar energy is absorbed by the atmosphere.

The conversion efficiency from herbivores to carnivores is the least efficient of the tropic levels with an average conversion of _____.

1 – 5%

The relationship between the amount of energy available for use and the amount of entropy in a food chain differs between trophic levels. Why would the amount of entropy increase from one trophic level to another in a food chain or energy pyramid?

energy is lost at each level as heat, which increases randomization

Entropy is greater at higher trophic levels than at lower levels.

True

Energy that is not passed on from one trophic level to the next is _______.

lost as heat

Why is a system’s work output limited?

Energy is lost as heat in each stage, causing the amount of energy available to decrease with each stage.

The amount of available energy changes between the trophic levels found in a food chain or energy pyramid.

Photos: leaves ➜ mouse ➜ snake ➜ hawk.

How would the amount of available energy differ in the trophic level of the mouse compared to the trophic level of the hawk?

Available energy would decrease from the mouse to the hawk.

Which of the following levels is the most efficient at energy conversion?

producers

Gross production is the amount of energy left after cellular respiration.

False

Which of the following is the most likely flow of energy in an aquatic ecosystem?

phytoplankton ® zooplankton ® fish ® mammal

Which of the following statements about entropy is true?

Entropy increases going from one trophic level to another.

Which of the following plant structures provides most of the water necessary for photosynthesis?

roots

C4 and CAM plants are _______.

adaptations to arid environments

Which of the following types of carbon fixation is least common for plants in arid locations?

C3

Which of the following is an output of photosynthesis?

oxygen

Different types of plants use different types of carbon fixation as adaptations to varying conditions.

True

The _______ in plants is directly responsible for absorbing light energy.

chlorophyll

Dark reactions require energy to proceed, while light reactions do not.

False

What is the main difference between C3 and C4 carbon fixation?

C3 processes take place throughout the leaf, while C4 processes take place in the inner cells.

How does the carbon dioxide necessary for photosynthesis enter plants?

through openings in the leaves called stomata

Photosynthesis is vital for maintaining levels of atmospheric oxygen.

True

How does energy acquisition in the deep sea differ from energy acquisition near the ocean’s surface?

Organisms in the deep sea do not have direct access to sunlight.

Marine snow is _______.

pieces of organic matter that were once part of living organisms

What are the two ways that organisms on the bottom of deep sea food chains acquire energy?

chemosynthesis and marine snow

Which of the following is not a possible source of energy for chemosynthetic organisms?

water

Which of the following creatures does not gain energy from marine snow either directly or indirectly?

zooplankton

Which of the following is required for photosynthesis to take place?

water

Which of the following statements about C3 carbon fixation is true?

C3 carbon fixation occurs in more plants than C4 carbon fixation.

Which of the following organisms is located only in the 3rd trophic level of the soil food web?

protozoa

Which of the following statements about energy and trophic levels is not true?

None of the above ——————————————————————————– The above… a. The amount of available energy decreases at each higher trophic level. b. The energy conversion efficiency decreases at higher trophic levels. c. The net production of energy is higher at lower trophic levels.

Which of the following is true about the efficiency of energy transfer in an ecosystem?

The less energy the organism requires, the more efficient the energy transfer.

Which of the following best explains why ecosystems need a continual influx of new energy?

Energy flows through an ecosystem and cannot be recycled.

Moving through trophic levels _______.

all of the above ——————————————————————————– The above… a. energy decreases b. entropy increases c. biomass decreases

Explain how waste heat is inevitable in ecosystems.

Energy is neither created nor destroyed by chemical processes, merely transferred. Since energy is also lost every time energy is transferred between organisms, that lost heat must go somewhere. That lost energy becomes waste heat in the environment.

Why are there different types of carbon fixation?

There are different types of carbon fixation, because plants are located in regions with different conditions. Plants that live in arid regions need to conserve water, while plants that live in more moist conditions will not need to conserve water. Plants that live in dry areas, or areas with higher temperatures have adapted modified methods of carbon fixation to help maximize their efficiency.

Which type of carbon fixation stores carbon dioxide in acid form?

CAM

Explain why photosynthesis is vital for life.

Photosynthesis is vital for plant life, because it provides plants with a means to produce energy. Photosynthesis indirectly provides organisms that feed on plants with energy as well. Organisms that feed on plants derive their energy from the plants, which obtained their energy from sunlight through the process of photosynthesis. Photosynthesis also helps maintain atmospheric levels of carbon dioxide and oxygen. Carbon dioxide is taken in by plants during photosynthesis, and oxygen is released.

Explain why lightning strikes can be dangerous even when an individual is not directly struck.

Lightning strikes are dangerous whether an individual is or is not in the path of the discharge. The current propagated by a lightning strike is actually what is harmful and the current can pass through the ground after striking. This means that even near-misses can be dangerous as the current travels through the ground.

Increases in entropy lead to _______.

irreversible changes

Ecosystem productivity is principally limited by _______.

sunlight and nutrient availability

Compare the light and dark reactions that occur in plants.

The light reactions occur when light is absorbed by the chlorophyll in plants. This light energy is converted to chemical energy in the thylakoids of the chloroplasts in the form of ATP and NADPH. Water splits, producing oxygen gas which is released through the stomata on plant leaves. The dark reactions occur in the stroma of the chloroplasts when carbon dioxide is converted to sugar using energy derived from ATP and NADPH.

Compare the light and dark reactions that occur in plants.

Light reactions need light to produce organic energy molecules (ATP and NADPH). They are initiated by colored pigments, mainly green colored chlorophylls. While dark reactions make use of these organic energy molecules (ATP and NADPH). This reaction cycle is also called Calvin Benison Cycle, and it occurs in the stroma. ATP provides the energy while NADPH provides the electrons required to fix the CO2(carbon dioxide) into carbohydrates.

Explain how waste heat is inevitable in ecosystems.

Energy is neither created nor destroyed only transferred. Since energy is lost every time it is transferred between organisms, that lost heat must go somewhere. That lost heat energy becomes waste heat in the environment.

Why are there different types of carbon fixation?

Different types are suited best for different types of plant who are in different locations and have different temperatures and resources.

Explain why photosynthesis is vital for life.

Without photosynthesis producers couldn’t survive. Without plants, primary consumers wouldn’t have food. Without primary consumers, secondary consumers wouldn’t have food. Without secondary consumers, tertiary consumers wouldn’t have food. Without tertiary consumers, quaternary consumers wouldn’t have food. Plants also gives out oxygen and take in carcon dioxide.

Explain why lightning strikes can be dangerous even when an individual is not directly struck.

If a person is in the path of the lightning discharge. If a person is not in the path of the lightning discharge. Up to 10 miles away from the rain area in a thunderstorm lightning can be dangerous, for where it hits other stuff and it can affect the nervous system, etc.

Bacteria in soil feed on _______.

organic matter

Why is energy flow through an ecosystem dependent upon continual energy transformations?

Organisms must gather energy to survive. This energy can come in different forms, depending upon whether the organism is an autotroph and gathers its energy from sunlight or a consumer that feeds upon autotrophs and/or other consumers. Processing plant and animal matter into usable chemical energy in this way requires transforming it. Plant matter is transformed by herbivores which are transformed by carnivores, maintaining the food webs that support an ecosystem.

Why is energy flow through an ecosystem dependent upon continual energy transformations?

If energy doesn’t transform organisms cant take it in the right way. And can’t pass it on.

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