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37 Cards in this Set
- Front
- Back
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(Most) Ecosystems rely on a supply of energy from... |
Sunlight |
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Photosynthesis |
The process of converting light energy to chemical energy in carbon compounds |
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Feeding |
The means by which chemical energy in carbon compounds flows through food chains |
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Energy released by respiration... |
is used in living organisms and converted to heat |
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What can living things not convert to other forms of energy |
Heat |
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What can living things convert to chemical energy to? |
Kinetic energy in muscle contraction, electrical energy in nerve cells and heat-generating adipose tissue are examples |
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What things can living things convert? |
Light energy (in the case of photosynthesis in plants and algae), carbon energy in carbon compounds |
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How is energy lost from ecosystems? |
The heat energy that is produced when organisms release energy via respiration and convert it to heat. |
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How is the length of food chains restricted? |
Energy losses between trophic levels restrict the length of food chains. |
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How is the biomass of higher trophic levels restricted? |
The energy losses between trophic levels restrict the biomass of higher trophic levels. |
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What 3 groups of autotroph carry out photosynthesis |
plants, eukaryotic algae (including seaweed that grows on rocky shores) and cyanobacteria |
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cyanobacteria |
A phylum of prokaryotic bacteria that obtain their energy through photosynthesis |
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What is an informal term ecologists refer to autotrophs as? |
producers |
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What is an inmportant quantative method for representing the energy flow through different trophic levels in a food chain? |
A Pyramid of Energy |
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Where are cyanobacteria abundant? |
In marine and freshwater ecosystems |
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Insolation |
A measure of solar radiation (often on maps, for example) |
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Why are there high levels of photosynthesis in tropical rainforests? |
The high level of insolation in those areas of the world. |
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Light energy becomes chemical energy... |
... by being stored in the chemical energy of carbon compounds via photosynthesis |
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How do producers absorb sunlight? |
Via chlorophyll and other photosynthetic pigments |
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How many organisms are there in a food chain (usually)? |
Between 2 and 5 |
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Energy released by respiration... |
is used in living organisms and converted to heat |
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What examples of cell activities are there that require the energy released from respiration? |
Synthesizing large molecules like DNA, RNA and proteins, pumping molecules or ions across membranes by active transport, and moving things around inside the cell, such as chromosomes or vesicles, or in muscle cells, the protein fibres that cause muscle contraction. |
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What is produced in cells to be used as energy? |
ATP |
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What supplies the energy for cell activities? |
ATP |
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How do cells produce ATP |
via respiration |
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What is the process of ATP production in detail, and why does it happen |
By respiration. In this process carbon compounds such as carbohyrdrates and lipids are oxidized. These oxidation reactions are exothermic and the energy released is used in endothermic reactions to make ATP. So cell respiration transfers chemical energy from glucose and other carbon compounds to ATP. This is because chemical energy in carbon compounds is not immediately usable by the cell, but the chemical energy in ATP can be used directly for many different activities. |
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Second law of thermodynamics |
Energy transformations are never 100% efficient |
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How does the second law of thermodynamics apply to energy use in organisms |
Not all of the energy from the oxidation of carbon compounds in cell respiration is transferred to ATP. The remainder is converted to heat. Some heat is also produced when ATP is used in cell activities. |
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Example of how some energy is lost in heat production in cell activities |
Muscles warm up when they contract. |
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Final form of energy |
Heat |
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Why is heat production also necessary in organisms |
Heat can be useful in making cold-blooded animals more active, and it is necessary for organisms to maintain their body temprature so that their enzymes can work properly. |
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According to the laws of thermodynamics, where does all energy eventually go? |
According to the laws of thermodynamics, heat passes from hotter to cooler bodies, so heat produced in living organisms is all eventually lost to the abiotic enviroment. |
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Biomass |
The total mass of a group of organisms. It consists of the cells and tissues of these organisms, including the carbohydrates and other carbon compounds that they contain. |
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How do ecologists measure biomass? |
They measure how much energy is added per year by groups of organisms to their biomass. The results are calculated per square meter so that different trophic levels can be compared |
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How are the three ways that biomasses in every trophic level shrink due to energy loss? |
1. Most of the energy digested and absorbed by organisms is released via respiration, the only left being in their bodies. 2.The organisms in a trophic level are not usually entirely consumed by organisms in the next trophic level (eg locusts can't eat everything, and lions can't eat bone) 3.Not all parts of food ingested by the organisms is digested and absorbed. Some material is indigestable and egested in feces. |
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What proportion of energy from the biomass of organisms in a trophic level becomes a part of the energy in the biomass of organisms in the next trophic level? |
10% |
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How does biomass (measured in grams) diminish along food chains |
In the loss of carbon dioxide and water from respiration, and the loss from the food chain of uneaten or undigested parts of organisms. |
