adaptations, interdependence and competition

• • An ecosystem is the interaction between a community of living organisms and their environment.
• • A community is two or more populations of organisms.
• • An ecosystem is two or more populations of organisms (usually many more) in their environment.
• • A population is all the organisms of the same or closely-related species in an area.
• Producer-Producers are plants and algae, which photosynthesise.
• Primary consumer-Primary consumers are herbivores, which eat producers.
• Secondary consumer-Secondary consumers are carnivores, which eat primary consumers.
• Tertiary consumer-Tertiary consumers are also carnivores. They eat secondary consumers
• The abundance is the number of organisms in an ecosystem and their distribution is affected by abiotic factors. These are factors that are non-living.
• Some plants have evolved for optimum growth in bright sunlight. An example of this is a cactus houseplant. Cacti originally come from deserts where they grow in bright sunlight. Other plants have evolved to grow in shade.
• Many orchids, which are also kept as houseplants, grow on trees in the rainforest and have evolved for optimum growth in darker conditions. If you were to put an orchid on a bright windowsill and a cactus in a dark corner of your room neither plant would grow well.
• Both animals and plants have evolved to grow healthily at their optimum temperatures. If you planted either your cactus or orchid houseplants outside in cold temperatures, they would die. Similarly, animals that have evolved to live at the North Pole, such as the polar bear, could not survive in warmer conditions.
• More people kill houseplants by overwatering than by under-watering them. Many plants cannot survive in waterlogged soils. Their roots are unable to respire, they rot and the plant dies. Other plants, such as pitcher plants, grow best in bogs where the moisture levels are high. Soil moisture meters can accurately determine how wet an area is.
• The pH of soils can have a huge effect on the plants that are able to grow in them. Some plants, like azaleas, grow best in acidic soils and will quickly die if planted in alkaline soils. Others, like clematis, prefer alkaline soils. Some, like the hydrangea, can grow in both. These plants are unusual in that their flower colour changes in different soils. Just like universal indicator paper, hydrangea flowers are pink in acidic soils and blue in alkaline soils.
• the abiotic factors are- light intensity, soil ph, temperature, moisture levels, soil mineral content, wind intensity and direction, carbon dioxide levels (for plants) , oxygen levels ( for aquatic animals).
• The pH of water can also affect the aquatic organisms that are found there. Different species have evolved to survive at different pH levels found within water.
• Many plants require high levels of soil minerals to grow well. An example of this is magnesium, which is required to produce chlorophyll. Plants with unnaturally yellow leaves may have a magnesium deficiency. Carnivorous plants, such as pitcher plants, have evolved to catch insects to supplement the low levels of minerals found in the soils in which they grow.
• The strength of the wind and its direction has a huge impact on where organisms are found within ecosystems. Many organisms prefer more sheltered locations. Plant seeds are more likely to settle and germinate there, and animals which depend upon these are more likely to live close to where they grow. The strength of the wind can also affect the growth of individual organisms.
• Carbon dioxide is a reactant in photosynthesis which means plants need it to survive. Areas with higher levels of carbon dioxide are more likely to have healthy plants growing. Farmers often release carbon dioxide within their greenhouses to maximise their crop yield. Woodlands often have higher carbon dioxide levels than open grassland, so many plants living in open areas have evolved mechanisms to overcome a shortage of carbon dioxide.
• Oxygen from the air and oxygen produced by aquatic plants dissolves in water. Without this, aquatic animals would suffocate and die. Healthy lakes and rivers have high levels of oxygen, and polluted waters often have low levels of oxygen. This pollution means that only certain species can survive there such as sludgeworms. These are bioindicator species because their presence or absence informs us about the condition of the habitat.
• Abiotic factors are non-living. They include light intensity, temperature and moisture levels. The abundance and distribution of living organisms in an ecosystem are affected by abiotic factors.
• A shingle beach has small stones instead of fine sand. Plant seeds can lodge between the small stones and start to grow, particularly at the top of the shore away from the waves. Two students set up a transect along a shingle beach. They started at top of the beach and worked towards the sea. Every five metres they placed a quadrat on the beach and measured the height of all the plants found.
• The abundance and distribution of organisms are affected by biotic factors, which are factors that are living.
• All animals require food to live. The availability of food is a major factor in how many animals live in an ecosystem. Areas like rainforests with rich food supplies have more species of life than other areas like deserts and the Polar Regions where there is less food.
• The arrival of new predators in an ecosystem can have a devastating effect. In balanced ecosystems, predators and prey have evolved together. Predators can catch enough prey to survive, but not so many that they kill all of their food.
• Biotic factors are living.

  They include:

  • availability of food
  • the presence of new predators and pathogens
• Both the abundance and distribution of living organisms in an ecosystem are affected by biotic factors.
• Red squirrels are native to Great Britain. They weigh around 300 grams, and about half the mass of the larger grey squirrel. The grey squirrel species was introduced around a hundred years ago from America by wealthy land owners who wanted a fashionable addition to their forests.

  The larger grey squirrel has provided competition for the native red squirrel, which has resulted in a lack of food for the species. Organisations like the Red Squirrel Support Trust have sampled the numbers of both squirrel types over time. Their results are shown below.
• All plants and algae need light to photosynthesise. 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’t look like a race to us because it happens slowly.
• 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.
• Plants require minerals for healthy growth. These include nitrates and magnesium. Without sufficient minerals plants suffer deficiency 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.
• 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.
• ompetition can be intraspecific, for example competition between oak trees in a forest, or interspecific such as when another species 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 evolution. Whole species that are unable to effectively compete may become extinct.
• All animals require food which provides them with energy and raw materials to complete life processes, without which they may die. Because of these, competition for food can be fierce. There are many birds which eat insects in our gardens, and some have evolved to only eat certain types of insect to reduce competition from other species. Others like the blue tit and great tit compete with other members of their own species and as well as others for different insects. Because food is so vital, many animals will fight for it.
• Animals within a species also compete for mates. This is essential so they can pass on their genes to their offspring. Animals have evolved to have an innate or natural drive to reproduce, and this competition often results in fights. In deer, and many others species, these fights competing for mates can often result in serious injury or death, but benefits the population as only the strongest pass on their genes to the next generation.
• The territories of animals contain all of the resources and conditions they need to survive. These include abiotic factors such as light, temperature and water, and oxygen for aquatic animals. There are also biotic factors such as food and predators. Many animals, including the cats in back gardens, will fight for territory.
• An example of intraspecific competition over territory would be between lions on the grass plains of Africa whereas interspecific competition would occur when another predator like leopards lived close to the lions.
• Plant adaptations can be structural, behavioural or physiological. Regardless of the type, all adaptations make organisms better suited to their ecosystem and provide them with a better chance of survival and reproduction, which are their ultimate aims. The adaptations that arise from competition are essential for the process of evolution. Survival of the fittest means survival of those best adapted.
• Structural adaptations of plants are the physical features, which allow them to compete. An example of this is the formation of spines, which are found on many species, such as cacti and roses, and can stop a plant being eaten by grazing animals. Other examples of structural adaptions include plants with wide-ranging, shallow roots to absorb lots of water after rain, large leaves to maximise photosynthesis and flowers, which attract insects to pollinate them.