ERTH 20 Lecture Notes - Lecture 11: Nekton, Countershading, Poikilotherm
7 May 2020
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Document Summary
Unlike plabkton, nekton are larger and often contain hard, dense body parts such as bones/organs. Stay afloat using: internal gas chambers (swim bladders) which the animal can inflate and deflate, actively swimming. Huge variety of methods: squid take and expel it through their siphon, fish contract and relax muscles along their sides so that their body moves in a wave from front to back and they move forwards. Their fins contribute to movement but also are used for braking, turning, and balance. Lungers wait for prey to come close. The faster fish swim the more energy they use. Cold-blooded fish have same temperature as their environment known as poikilothermic and tend to be slower. Warm-blooded fish maintain their body temperatures higher than their environment known as homoeothermic and tend to be faster. Symbiosis: individuals can form relationship with other organisms to help them survive, commensalism. Less dominant organisms benefit without harming the dominant organism: mutualism, parasitism.
