carbon dioxide one of the gases in air. Plants need it to make their food. chlorophyll the green substance in plants that traps sunlight. commensalism a relationship when one species benefits and the other remains unaffected. community all the populations in an ecosystem. competition a relationship between different species that have the same needs. consumers living things that obtain their food from other living things. decomposers microorganisms and fungi that break down dead animal and plant materials. deforestation the disappearance of forests, which leads to erosion. desertification the slow transformation of fertile land into desert. ecosystem all the organisms living in one place, as well as the physical environment they live in. elaborated sap the food that plants make. It is distributed through phloem vessels. endangered species living things that are at risk of becoming extinct. environment everything that affects a living thing. food chain the representation of how living things feed on other living things. food web many food chains joined together and interconnected form a food web. herbaceous herbaceous plants have soft flexible stems. mutualism a relationship between two species when both benefit. parasitism a relationship when one species benefits while the other suffers. phloem vessels tubes that transport elaborated sap to all parts of the plant. photosynthesis the process by which plants make their own food. pollution the accumulation of rubbish and harmful substances in air, water and soil. population all the organisms of one species in an ecosystem. producers living things that make their own food. raw sap the mixture of water and mineral salts that plants absorb through their roots. salinity the amount of salt dissolved in water. scavengers animals that feed on the remains of dead animals. xylem vessels tubes which transport raw sap up the stem of a plant to the leaves.
Ecosystems consist of the physical environment and the living beings that inhabit it. Discovering the components of ecosystems and the relationships that exist between the living beings that inhabit them will allow you to understand how the environment around us is organised and how we can look after it.
An ecosystem is made up of a specific physical medium and the living beings that inhabit it and interact with each other within it.
Ecosystems can be terrestrial or aquatic, and they are of different sizes. They may be small, like a lagoon, or large, like the Amazon rainforest. The largest ecosystem of all is the biosphere, which consists of all of the living beings that inhabit planet Earth.
The components of ecosystems are the physical medium as well as all of the living beings that inhabit it, which may have different characteristics:
- The physical medium: is the result of different elements, called environmental factors. These may be, for instance, temperature, humidity, precipitation, light or the type of soil. It may be terrestrial or aquatic:
- Terrestrial environments: where terrestrial ecosystems are developed. These physical environments are highly influenced by temperature, precipitation, humidity, light and soil type. Temperature and precipitation depend on the regional climate, and vary over the year. Together with humidity and soil type, they decide which plants will grow in the soil. Vegetation, in its turn, conditions the type of herbivores that inhabit the ecosystem and enable carnivores to exist. Light is also very important, since it is needed for plants to obtain nourishment through photosynthesis.
- Aquatic environments: where aquatic ecosystems develop. The most important factors in these types of environments are salinity and light. Salinity is the amount of salt in the water and it determines what type of aquatic beings inhabit an ecosystem. Depending on the level of salt, the water may be fresh, like the water in rivers, or salt water, like in oceans. The living beings that inhabit one type of water or another will be different. Another factor that affects living beings in aquatic systems is light, since plants and algae grow only in places where there is light. If there is no light, they cannot perform photosynthesis, which means that in deep parts, or in places where the water lacks transparency, they cannot develop. Factors such as air temperature and precipitation are less important in aquatic environments.
- Living beings: the type of living beings in an ecosystem depends on the physical environment they inhabit. They interact with each other in many ways and can be grouped into different levels:
- Species: are groups of animals with similar characteristics that can reproduce and generate young with the same characteristics. Examples of animal species include elephants and dolphins, whereas plant species include daisies and firs.
- Populations: are groups of animals of the same species that live in an ecosystem. For example, there may be a population of tigers in an ecosystem.
- Communities: are all of the populations of different species that live in an ecosystem. For example, there may be a community consisting of firs, deer, ants, etc.
Photosynthesis is a process where plants use light from the Sun to transform substances such as water, mineral salts and carbon dioxide, which they absorb through their roots and leaves, into food.
Living beings in an ecosystem depend on the physical environment, which is affected by these living beings. For example, depending on the climatic conditions of a place, meaning the temperature and precipitation, one or another type of vegetation will grow in an environment. Vegetation, in its turn, will decide what type of animals inhabit the ecosystem. For example, animals that feed on fruit need to live in places where there are fruit trees.
Furthermore, living beings also change the environment they inhabit. An example is moles, which dig underground tunnels and change the soil.
However, living beings also have the ability to adapt, which means that the living beings in any environment, terrestrial or aquatic, can adapt to it by developing characteristics that enable them to live in it. Therefore, for instance, camels, which live in deserts, accumulate fat reserves in their humps, which they use to feed themselves; and dolphins have developed fins, which enable them to move through the water.
The environment where a living being exists consists of the physical environment that they inhabit and the interactions they have with the other living beings. In the case of human beings, which are present in almost all regions of the planet, the environment encompasses all of the living beings that live on our planet and in our surroundings. These surroundings consist of numerous ecosystems, which we often damage through our activities.
The activities of human beings in the environment have been very significant in recent centuries, when industry, technology, construction, farming and agriculture have undergone enormous development. The unrestrained growth of these activities has been very harmful to the environment, and has given rise to the following problems:
- Pollution: as a consequence of our economic activities, humans release elements into the environment that damage it. These may include pollutant gases, emitted through the exhaust pipes of vehicles and factory chimneys, and the dumping of water and solid waste, such as plastic and other rubbish, by industry. All of these degrade the environment and negatively affect the living beings that form part of it. For example, the soap used to clean your clothes, dishes, etc. is very difficult to eliminate at the water treatment plant, which means that it is inevitable that part of it is dumped back into rivers.
- Global warming: the Earth’s atmosphere contains a small quantity of carbon dioxide, which naturally retains some of the heat generated by the rays of the Sun. This ensures that the temperature of the planet is suitable for life. Due to the fuel used by means of transport and industry, human activity generates huge emissions of carbon dioxide. These large volumes of carbon dioxide accumulate in the atmosphere and retain more heat than necessary, which causes the temperature of the planet to increase. This temperature increase may have serious consequences for the Earth and the living beings that inhabit it.
- Deforestation: deforestation is a consequence of the unrestrained felling of trees to obtain wood or land for farming and constructing buildings. It causes the layer of vegetation that covers the soil to disappear, leaving the soil unprotected from factors such as water or wind. Erosion caused by these elements, makes the soil sandy, which complicates the growth of vegetation.
- The loss of biodiversity: biodiversity is the number of species of living beings that form an ecosystem. It is very important that an ecosystem maintains its diversity, because all of the species participate in feeding relationships and relationships of other types, meaning that certain living beings enable others to exist. Deforestation, global warming and pollution lead to the loss of biodiversity.
5.1How to protect ecosystems
To protect the environment and all of the living beings that form part of it, we can develop certain habits that help to maintain our surroundings and avoid actions that may damage them. Some advice on taking care of the environment includes the following:
- Recycle rubbish: it is important to put the rubbish you generate in the correct containers to assist with recycling. This is one way to contribute to reducing the huge volume of waste that human beings generate. What is more, you should not throw rubbish onto the street or onto the ground in nature, nor tip oil down the toilet or into the drains in your house.
- Respect flora and fauna: It is important to respect the living beings around us, and their environment.
- Save water: we often use more water than we need in our daily lives. We should save water, because it may become a scarce resource. With this objective, use the shower instead of taking a bath, turn off taps when you are not using them, and make sure that they are properly closed.
- Save electricity: we can save electricity and avoid the pollution that its production often causes, by turning off lights and domestic appliances that we are not using, and using them less.
- Save fuel: in order to avoid generating carbon dioxide emissions in the atmosphere, we can reduce fuel usage by using group forms of public transport, where many people fit at the same time, such as buses. In this way, many more people are transported using the same amount of fuel.
Further to these actions, which each person can do individually, the authorities need to establish laws to protect the environment. This is the goal of protected areas, for example, which are areas identified by the government to enable the protection of landscapes and any species found there that are in danger of extinction.
ECOSYSTEM. 5TH GRADE
2. READ AND LISTEN! WITH QUIZLET
–PRODUCERS AND CONSUMERS
–IDENTIFY AND LABEL ECOSYSTEMS AND FOOD CHAIN
–TYPES OF ORGANISMS
-MORE GAMES: SCHOLASTIC