Unit 8: Topic 2 - Energy Flow Through Ecosystems Flashcards
Explain the difference between endotherms and ectotherms and how that impacts their behaviors.
The main difference between endotherms and ectotherms is how they maintain their body temperature: endotherms do it by using heat generated from metabolism, while ectotherms regulate their body temperature through their environment rather than internally. This results in differences in regulating metabolism and in behaviors. Endotherms have higher rates of metabolism since they depend on heat energy from metabolism, while ectotherms expend energy on behaviors such as shivering to regulate temperature. The main 4 mechanisms by which ectotherms exchange heat with their environment are radiation, conduction, convection, and evaporation. Radiation is exchanging heat energy through electromagnetic waves (an example of this is how the Sun’s rays heat up the Earth). Conduction is the transfer of heat energy through direct physical contact. Convection is the transfer of heat through movement in a fluid or gas (for example, warmer parts of a liquid or gas move upward while cooler parts move downward). Evaporation is the transfer of heat due to the phase change of water from a liquid to a gas (this plays a big role in sweating, where excess body heat is used to evaporate sweat, leading to the body cooling down).
How does energy availability impact the reproduction strategy used by an organism?
Depending on how much energy is available, an organism can change how often it reproduces, how it raises offspring, whether it undergoes sexual or asexual reproduction and other similar reproductive strategies. An example of this would be that if there was less energy available, organisms would generally produce fewer offspring than if there was more energy available.
What is the relationship between the size of an organism and metabolic rate?
Generally, the smaller the organism, the higher the metabolic rate per unit body mass is.
Explain what a net gain of energy in an organism would result in, and a net gain of energy loss.
If an organism experiences a net gain of energy, it would put that energy towards growth or store it for later use. Meanwhile, if an organism experiences energy loss, in the short term, it would lose mass. If this energy loss continues, the organism can die.
How does energy availability impact population size?
Generally, less energy available means a smaller population size because a higher population size means there are more organisms and thus more energy spent.
How does energy availability impact population size in the whole ecosystem?
Changes in energy sources used by producers, such as the sun, can result in changes in the population size of producers, which impacts all the trophic levels above them.
What are the two main types of autotrophs and how do they capture energy from the environment?
The two main types of autotrophs are photosynthetic organisms and chemosynthetic organisms. Photosynthetic organisms use the process of photosynthesis to capture energy from sunlight, while chemosynthetic organisms capture energy from inorganic molecules in the environment (a common example of this type of organism is one that lives in a hydrothermal duct). Unlike most photosynthetic organisms, chemosynthetic organisms don’t need oxygen.
What role do heterotrophs play in the flow of energy in an ecosystem?
Heterotrophs gain their energy from organic compounds like carbohydrates, lipids, or proteins produced by other organisms. To get this energy, they either consume autotrophs or other heterotrophs, resulting in the flow of energy from producers/autotrophs to primary consumers (heterotrophs that directly eat the producers) to secondary consumers (heterotrophs that consume the primary consumers), and so on.
Explain why a pyramid model is a good representation of the flow of energy in an ecosystem?
A pyramid model is a good representation of the flow of energy in an ecosystem because energy is lost through heat in each trophic level, meaning that each trophic level only gains 10% of the energy from the previous level (this flow of energy is directional, meaning it only goes up the trophic levels). This also results in lower population sizes for the higher trophic levels than for lower levels, meaning the pyramid model is a good representation of both population size and the flow of energy.
