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Interactions with the Environment 2 major responses to the environment by organisms:. Conformation. In conformers the internal environment fluctuates with the external environment. Regulation.
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Interactions with the Environment 2 major responses to the environment by organisms: Conformation In conformers the internal environment fluctuates with the external environment Regulation In regulators the internal environment is maintained at a set point despite changes in the external environment
Conformers Osmoconformation is being isosmotic to the surrounding environment. Their body fluids will be isotonic to their surroundings. These includes crabs, shrimps, jelly fish and other marine organisms. Poikilotherms are animals whose body temperature fluctuates with their surroundings. Often called ectotherms these include snakes, lizards and marine fish.
Conformers Features Limited in their geographical range. Activities limited by conforming state. Often have reduced energy needs compared to regulators. May have more energy available for growth relatively speaking compared to regulators.
Regulators Osmoregulation is the ability of organisms to maintain a constant water balance in their cells These include mammals, marine and freshwater fish. Homeotherms are animals that can maintain their body temperature independently of the environmental temperature. These organisms are called endotherms and the heat energy comes from metabolic processes. These include mammals and birds.
Regulators Features Use a lot of energy maintaining their internal environment. Require considerably more energy when compared to conformers beyond that needed for growth and repair, so they will need to feed more often. Can be active in a wide range of environments and inhabit a wider range of geographical areas than conformers.
The Survival strategies of Dormancy Development of the organism is suspended due to unfavourable conditions. Metabolic processes are slowed or suspended until conditions become more favourable. Dormancy occurs in plant seeds, temperate and arctic mammals. Organism must have a resistant stage and synchronised life cycle to environmental conditions.
Synchronisation Predictive strategy Dormancy occurs before the unfavourable conditions, triggered by a stimulus like daylength or temperature. Consequential strategy Dormancy happens as a result of unfavourable conditions. Can result in substantial loses but can mean better utilisation of resources.
Types of Dormancy Resting Spores Diapause Torpor Aestivation Hibernation
Torpor Reduction of body temperature compared to external temperature e.g. bats, mice and humming birds. Diapause Dormancy allowing them to suspend development between autumn and spring. E.g. deer delay implantation so young are born in spring. E.g. insects pupate from Autumn to spring This is a predictive strategy.
Hibernation - escaping cold weather and lack of food. Animals prepare by building up fat store before and slow metabolism during (heart rate). This can be predictive or consequential. Aestivation - occurs in response to hot, dry conditions. Snails seal shells if it is dry, lungfish burrow into mud. This is a consequential strategy.
Resting Spores - a hard case is formed around seed or spore. Can remain viable for long periods of time. This is a consequential strategy.
Life cycles Organisms have a variety of life cycles. Survival strategies exist to ensure organisms pass on their genetic information to their offspring. Reproduction can either be once or many times depending on species.
