The Effects of Abiotic & Biotic Features on the Distribution of Plants and Animals in Terrestrial & Aquatic Habitats
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The Effects of Abiotic & Biotic Features on the Distribution of Plants and Animals in Terrestrial & Aquatic Habitats There are many abiotic (physical) factors which affect the distribution of plants and animal in their habitats. Light is a major abiotic factor, as it is the source of energy for photosynthesis, which in turn means it influences all producers and consumers (directly or not). The amount of light available is a major factor in deciding where plants can survive. For instance terrestrial plants which are shade-tolerant can be found underneath trees, whereas those who are not only grow where there is a plentiful supply of sunlight. Similarly in aquatic environments some plants must have leaves on the surface of the water in order to photosynthesise, while others can survive under the water, where less light can penetrate. The temperature of a habitat will provide further limitations to which organisms can survive there. Nearly all living organisms have an optimum temperature range to live, so changes to the temperature will affect the rate they grow, and will affect their evolution.
So depending on the amount of water available different species of plants will be distributed accordingly. Terrestrial animals are also heavily affected by the availability of water, meaning they are also affected by the availability of water. Animals which are evolved to conserve water and to lose as little through evaporation will be found in dry hotter environments, while those who are not as good at that will be found in the places where water is less scarce. Salinity can affect the distribution of organisms, especially plants because it is harder for water to pass into the roots by osmosis when outside the roots there is a high water potential. Halophytes are plants which can tolerate high levels of salt, they are usually found in estuaries and salt marshes, where other plants cannot be found. In aquatic habitats the flow of water can effect the distribution of organisms. The flow of water can move organisms from one place to another; very fast flowing water can often make it difficult for any organisms to survive in one place, as they are washed away.
Organisms don't just have to compete with others from within their species (intraspecific competition) but also with organisms from other species (interspecific competition). This competition can lead to the displacement of one species - i.e. their distribution. While organisms have to deal with competition they also have predation to cope with. The distribution of a species is also determined by the presence or absence of prey and/or predators. Some organisms produce chemicals which repel other organisms (which may be of the same species - or not). This mostly applies to terrestrial animals that use chemicals to mark their territories, in order to deter other members of the species. This can reduce the distribution of some organisms in an area. Some ants produce pheromones when in danger, these pheromones warn other members of the species of the danger. The dispersion of some plants rely upon animals to disperse their seeds. Similarly many plants rely on insects for pollination, and without the insect they would be unable to reproduce effectively. Probably the most significant biotic factor which affects organisms is the influence of humans, we often dictate which organisms grow where, while being hunters, fishers, farmers, developers and polluters to name a few activities which affect other organisms.
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