All living organisms encounter situations that cause stress--events or conditions that force them to adapt, or change, to meet a challenge. Read the examples on on the slides below to see some ways organisms adapt to the various stressors they face.
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As human beings develop residential and commercial properties, they invade natural habitats. The animals that live there are stressed because their normal sources of food disappear. Many animals adapt to this stressor by changing their behavior. For instance, instead of the berries and small animals it used to eat, this bear has adapted to a new source of food—human trash.
Did you know that organisms the size of bacteria can experience stress? The marine microbes in this photo have adapted to the stressful competition for nutrients, energy, and a suitable temperature range by locating themselves in or near hydrothermal vents deep in the ocean. The heat from these volcanic vents keeps the bacteria warm, and the chemicals released by the vents provide nutrients. These bacteria have even adapted to their lack of energy from the sun. Unlike microbes nearer the water’s surface, these bacteria make energy from chemosynthesis rather than photosynthesis.
Humans require their companion animals to adapt all the time. Think about training a puppy to use the bathroom outside. As stressful as the training is for the humans, it’s also stressful on the puppy. The puppy must learn to adapt to meet the challenge of living harmoniously with its human family. For instance, its instincts may tell it to mark its territory throughout the house while its trainers try to tell it otherwise. |
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Think about the noises in a big city: car horns honking, jackhammers breaking up pavement, trucks backing up, people talking on cell phones or hailing a cab, radios blaring. All that background noise can be stressful. What are some ways in which people adapt to the noise? Are the effects of these adaptations positive or negative?
People talk louder to be heard over the noise. That works in the short term but can strain their vocal cords over time. People wear noise-canceling headphones to block out the noise. That can save their hearing, but it also cuts them off from other people and can make them dangerously unaware of their surroundings.
In this lesson, we will explore in greater detail how stress affects our lives, and we’ll look at how our adaptations to stress can have effects on our health.
