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一个神秘的小的习惯,从自己的嘴里
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相关概念视频
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A fixed action pattern (FAP) is a specific, hard-wired sequence of behaviors that occurs in response to an external stimulus, called a sign stimulus. The behavior is “fixed” because it is essentially unchangeable—proceeding similarly across individuals of a species every time it occurs.
Three-Spined Sticklebacks
A classic example of a FAP was described in three-spined stickleback fish by Nikolaas Tinbergen in the 1930s. During the breeding season, the male fish develop a red...
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Nonconscious mimicry occurs when individuals alter their mannerisms to match the behaviors and expressions of those nearby, without intention.
The concept of nonconscious mimicry is not a new one. How often do you find yourself mimicking someone’s behavior or speech, or even beginning to like the same things that they do? Such actions relate to forming affiliation and fitting in within social situations. Here, this phenomenon will be explored from various aspects to understand how...
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Overview
Constrained by limited energy and resources, organisms must compromise between offspring quantity and parental investment. This trade-off is represented by two primary reproductive strategies; K-strategists produce few offspring but provide substantial parental support, whereas r-strategists produce much progeny that receives little care. These strategies are related to an organism’s survival likelihood across its lifespan, which is represented by a survivorship curve. Three...
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Many animals exhibit parental care behavior, including feeding, grooming, and protecting young offspring. Parental care is universal in mammals and birds, which often have young that are born relatively helpless. Several species of insects and fish, as well as some amphibians, also care for their young.
Birds
Parental care can occur even before hatching in birds, when parents sit on their eggs to incubate them. After hatching, the parents provide food for their offspring, and may continue to...
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Evolution shapes the features of organisms over time, ensuring that they are suited for the environments in which they live. Sometimes, selection pressure leads to the rise of similar but unrelated adaptations in organisms with no recent common ancestors, a process known as convergent evolution.
The structures that arise from convergent evolution are called analogous structures. They are similar in function even if they are dissimilar in structure. Further, structures can be analogous while...
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Small population sizes put a species at extreme risk of extinction due to a lack of variation, and a consequent decrease in adaptability. This weakens the chances of survival under pressures such as climate change, competition from other species, or new diseases. Large populations are more likely to survive pressures such as these, as such populations are more likely to harbor individuals that have genetic variants that are adaptive under new stresses. Small populations are much less...