__________________________ are necessary abiotic material for organisms to grow and survive.

carbon dioxide, hydrogen, and oxygen

Flow of Energy in Ecosystems Review #1

Flow of Energy in Ecosystems Review #2

Roles of Organisms and Flow of Energy in Ecosystems

Vocabulary Starter - Flow of energy in ecosystems

Assessment of Energy Flow in Ecosystems - Starter Quiz

All animals, most protists, all fungi, and many bacteria are het- erotrophs. Unlike autotrophs, heterotrophs cannot manufacture their own food. Instead, they get energy by eating other organisms or organic wastes. Ecologically speaking, heterotrophs are consumers. They obtain energy by consuming organic molecules made by other organisms. Consumers can be grouped according to the type of food they eat. Herbivores eat producers. An antelope that eats grass is a herbivore. Carnivores eat other consumers. Lions, cobras, and praying mantises are examples of carnivores. Omnivores eat both producers and consumers. The grizzly bear, whose diet ranges from berries to salmon, is an omnivore. Detritivores (dee-TRIET-uh-VAWRZ) are consumers that feed on the “garbage” of an ecosystem. This waste, or detritus, includes organisms that have recently died, fallen leaves, and animal wastes. The vulture shown in Figure 18-8 is a detritivore. Many bacteria and fungi are detritivores that cause decay by breaking down complex molecules into simpler molecules. So, they are specifically called decomposers. Some of the molecules released during decay are absorbed by the decomposers, and some are returned to the soil or water. Decomposers make the nutrients that were contained in detritus available again to the autotrophs in the ecosystem. Thus, the process of decomposition recycles chemical nutrients. Copyright © by Holt, Rinehart and Winston. All rights reserved. 368 CHAPTER 18 ENERGY FLOW When one organism eats another, molecules are metabolized and energy is transferred. As a result, energy flows through an ecosystem, moving from producers to consumers. One way to follow the pattern of energy flow is to group organisms in an ecosystem based on how they obtain energy. An organism’s trophic (TRAHF-ik) level indicates the organism’s position in a sequence of energy transfers. For exam- ple, all producers belong to the first trophic level. Herbivores belong to the second trophic level, and the predators belong to the third level. Most terrestrial ecosystems have only three or four trophic lev- els, whereas marine ecosystems often have more. Food Chains and Food Webs A food chain is a single pathway of feeding relationships among organisms in an ecosystem that results in energy transfer. A food chain may begin with grass, which is a primary producer. The chain may continue with a consumer of grass seeds—a meadow mouse. Next, a carnivorous snake may kill and eat the mouse. A hawk then may eat the snake, as shown in Figure 18-9. The feeding relationships in an ecosystem are usually too com- plex to be represented by a single food chain. Many consumers eat more than one type of food. In addition, more than one species of consumer may feed on the same organism. Many food chains inter- link, and a diagram of the feeding relationships among all the organisms in an ecosystem would resemble a web, as shown in Figure 18-10. For this reason, the interrelated food chains in an ecosystem are called a food web.

Based on the provided sources, here is a comprehensive extraction of the information regarding the water cycle, energy transfer, and Earth's wind systems, organized into key points: The Water Cycle and Its Reservoirs • Definition: The water cycle is the continuous movement of water among various reservoirs on Earth. • Water Reservoirs: These are storage locations for water and include: ◦ Oceans, seas, and lakes. ◦ Rivers, glaciers, soil, and rocks. ◦ The atmosphere and living organisms. • Total Volume: The total amount of water on Earth does not change, even when it changes state, because it is constantly being replaced or recycled through the cycle. Main Processes and Energy Transfer The movement of water through the cycle is driven by energy (thermal energy from the Sun) and force (gravity and wind). • Energy Gain (Absorption): ◦ Melting: Water changes from a solid state (ice) to a liquid state and gains energy. ◦ Evaporation: Liquid water changes into a gas state (water vapor) by gaining thermal energy. ◦ Transpiration: A specialized type of evaporation occurring in plants where water vapor is released through tiny holes in leaves called stomata. Approximately 10% of water vapor in the air comes from transpiration. • Energy Loss (Release): ◦ Condensation: Water vapor (gas) cools down and changes back into liquid water, releasing energy. ◦ Freezing: Liquid water changes into a solid state (ice) and loses energy. • Other Key Steps: ◦ Precipitation: Water falls back to Earth as rain, snow, sleet, or hail (snow pellets). ◦ Runoff: Water flows over Earth's surface into streams, rivers, and eventually larger bodies of water like oceans. ◦ Collection: Rainwater is collected in different water bodies to start the cycle again. Forces Driving Water Movement • Gravity: The main force that pulls water downward. It is responsible for: ◦ Bringing precipitation (rain and snow) from clouds to the surface. ◦ Moving ice in glaciers from higher to lower elevations. ◦ Causing liquid water to flow downhill into rivers and seas. ◦ Leakage: Pulling liquid water down into the ground to reach groundwater reservoirs. • Wind: Another force that affects water movement and transports water to different locations on Earth. Atmospheric Processes • Cloud Formation: Water vapor attaches to particles such as dust or smoke in the air and condenses into tiny droplets. When millions of these droplets join, they become heavy and fall as rain. • Convection: The transfer of heat in liquids and gases. ◦ Warm air/liquid: Becomes less dense, lighter, and rises upward. ◦ Cold air/liquid: Is more dense, heavier, and moves downward to replace the warm fluid. ◦ This process leads to convection currents, which help determine regional climates and drive wind and ocean currents. Solar Radiation and Climate The amount of solar energy reaching Earth differs from place to place, which affects the weather: • Hottest Regions (Equator): Sun rays fall perpendicular (vertical). Heat is concentrated on a small area, making the weather hot. • Moderate Regions: Sun rays fall semi-inclined. Heat is distributed over a larger area, making the weather warm. • Coolest Regions (Poles): Sun rays fall very slanted (inclined). Heat is spread over a very large area, making the weather very cold. Earth's Wind System • Wind Formation: Wind is generated when warm air (heated by the Sun) rises and is replaced by cooler air flowing from nearby areas. • Factors Affecting Wind: The amount of solar radiation and the rotation of Earth determine global wind directions. • Global Wind Cycle: Unequal heating between the equator and the poles generates a constant wind system. Warm air rises at the equator and moves toward the poles, while cold air from the poles moves toward the equator. • Importance: If there were no wind, the equator would become extremely hot, the poles would freeze solid, and many ecosystems would disappear. Practical Examples • Turkey’s Salt Lake: High evaporation in the summer can turn this large lake into a small puddle or dry it up completely. It is a critical site for flamingos, which migrate there to breed and feed on algae in the shallow, warm water.

Try it Assessment of Gab FOOD CHAIN - Label organism in the food chain as herbivores, carnivores, and omnivores. (2) Identify the relationships among the different trophic levels in a food chain. (3) trace the flow of energy in an ecosystem

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