Competition in plants
Light
All plants and algae need light to photosynthesisA chemical process used by plants to make glucose and oxygen from carbon dioxide and water, using light energy. Oxygen is produced as a by-product of photosynthesis. Algae subsumed within plants and some bacteria are also photosynthetic.. Plants compete for light by growing quickly to reach it and often shade other plants with their leaves. When an old tree in a forest dies and falls to the ground, there is a race to fill in the gap in the canopy. It doesn鈥檛 look like a race to us because it happens slowly.
Water from the soil
Water is a reactant in photosynthesis and it is essential that plants have a regular supply of water for the process to occur. Some fully grown trees, like the oak tree, lose a staggering 150 litres of water per day, which is used to transport materials through the plant to the leaves. Some plants have roots that are shallow but extend a long way from the tree to maximise the update of water after rainfall. Others have roots that are deep to find stores of underground water.
Minerals from the soil
Plants require minerals for healthy growth. These include nitrateThe chemical absorbed from the soil by plants to produce their protein. and magnesium. Without sufficient minerals plants suffer deficiencyIn the diet, a deficiency happens if there is too little of a particular nutrient. diseases because they cannot grow healthily. Plants that grow in soils with few minerals, such as bogs, have evolved different ways of accessing nitrates. Some, like the Venus flytrap and pitcher plants, have evolved to be carnivorous and consume insects, enabling them to grow more successfully than their competitors on mineral poor soil.
Space
Plants also require space for healthy growth. This means their leaves are not shaded which maximises photosynthesis. Some gardeners have experimented by planting vegetables very close together. These result in much smaller vegetables being produced.
Competition can be intraspecific competitionThe competition between organisms within the same species., for example competition between oak trees in a forest, or interspecific competitionThe competition which occurs between organisms of different species for a common resource. such as when another speciesA type of organism that is the basic unit of classification. Individuals of different species are not able to interbreed successfully. of tree like birch or yew grew next to oak trees. When a woodland tree dies, other younger trees compete to replace it. This competition ensures the growth of the healthiest individuals, and maintains vigour in the population.
Individuals within a species that cannot compete effectively are unlikely to reproduce, and may die. This is known as survival of the fittest and is a driver for evolutionThe process of change in the inherited traits of a population of organisms from one generation to the next.. Whole species that are unable to effectively compete may become extinctA species that has completely died out..