Environment -1: Ecology & Biomes
Key Ecology Concepts
Ecology is the scientific study of the distributions, abundance and relations of organisms and their interactions with the environment. Ecology includes the study of plant and animal populations, plant and animal communities and ecosystems.
Autecology and Synecology
Synecology is concerned with the study of groups of organisms—the community, hence, it is also called community ecology. Both have developed independently, although the knowledge of both of them is necessary for the understanding of the individual, population, or ecosystem. Autecology is experimental and inductive. Synecology is philosophical and deductive.
Autecology, because it is concerned with the relationship of an organism to one or more variables such as light, temperature, moisture, or salinity, is easily quantified and subject to experimental design both in the laboratory and in the field. Synecology is largely descriptive and not easily subject to experimental design.
Various Ecological Units
The concepts of ecological units, such as population, community, and ecosystem, are at the basis of ecological theory and research and have increasingly become the focus of conservation strategies. Concepts of these units still suffer from inconsistencies and confusions over terminology.
The different concepts are treated here together as a common “conceptual cluster,” with similar ecological functions (roles) and similar problems in their definition and use. An analysis of the multitude of existing terms and concepts that have been developed for these units reveals that they differ with respect to at least four basic criteria:
(i) the questions as to whether they are defined statistically or via a network of interactions;
(ii) if their boundaries are drawn by topographical or process-related criteria;
(iii) how high the required internal relationships are; and
(iv) if they are perceived as “real” entities or abstractions by an observer.
The various definitions cannot be easily sorted into just a few types, but they can be characterized by several independent criteria. Serious problems arise if the different possibilities of defining ecological units are not recognized and if the concepts are perceived as self-evident.
Why population and not species is smallest ecological unit?
Evolution is often defined as the change in genetic composition of a population over time. The genes of an individual are what determine whether or not it is selected.
As populations are the smallest unit that actually evolves, it is reasonable to call them the “unit of evolution”. Individuals are usually called the “unit of selection” as whether an individual lives /dies /reproduces changes the genetic composition of the next generation. Selection can occur at multiple levels with gene selection or individual selection being primary.
Communities are tightly integrated entities consisting of interdependent species (the community-unit concept) vs. the view that species co-occur largely according to the individualistic response of each species to spatially variable environmental conditions (the individualistic concept).
Despite the debate regarding the concept of an ecological community, the discipline of community ecology has thrived and remained a key pillar of the broader field of ecology, with intense debates over the importance of competition in driving community structure and the relative importance of processes occurring at different spatial and temporal scales, among others.
Producers, Consumers and Decomposers:
Producers are any kind of green plant. Green plants make their food by taking sunlight and using the energy to make sugar. The plant uses this sugar, also called glucose to make many things, such as wood, leaves, roots, and bark. Trees, such as they mighty Oak, and the grand American Beech, are examples of producers.
Consumers have to feed on producers or other consumers to survive. Deer are herbivores, which means that they only eat plants (Producers). Bears are another example of consumers. Black bears are omnivores and scavengers, like skunks and raccoons, which means that they will eat just about anything. In a forest community, Black Bears will eat blueberries, bugs, acorns, and many kinds of nuts.
Decomposers are the garbage men of the animal kingdom; they take all the dead animals and plants (consumers and decomposers) and break them down into their nutrient components so that plants can use them to make more food. Decomposers in the forest come in many different shapes and sizes. Shelf fungus is a fungus that grows on the sides of trees. It grows into the tree and decomposes it slowly. Have you ever been walking through the woods and come across a dead log that falls apart and is full of dirt? That is because decomposers have been eating and digesting that log for several years, turning it into dirt that is wonderful for plants.
An ecosystem includes all of the living things (plants, animals and organisms) in a given area, interacting with each other, and also with their non-living environments (weather, earth, sun, soil, climate, atmosphere). Ecosystems are the foundations of the Biosphere and they determine the health of the entire earth system.
In an ecosystem, each organism has its own niche or role to play. The very complex, wonderful interaction of living things and their environment, has been the foundations of energy flow and recycle of carbon and nitrogen.
Anytime a ‘stranger’ (living thing(s) or external factor such as rise in temperature) is introduced to an ecosystem, it can be disastrous to that ecosystem. This is because the new organism (or factor) can distort the natural balance of the interaction and potentially harm or destroy the ecosystem. Click to read on ecosystem threats (opens in new page
Usually, biotic members of an ecosystem, together with their abiotic factors depend on each other. This means the absence of one member or one abiotic factor can affect all parties of the ecosystem. Unfortunately, ecosystems have been disrupted, and even destroyed by natural disasters such as fires, floods, storms and volcanic eruptions. Human activities have also contributed to the disturbance of many ecosystems and biomes.
Provisioning Services are ecosystem services that describe the material or energy outputs from ecosystems. They include food, water and other resources.
Food: Ecosystems provide the conditions for growing food. Food comes principally from managed agro-ecosystems but marine and freshwater systems or forests also provide food for human consumption. Wild foods from forests are often underestimated.
Raw materials: Ecosystems provide a great diversity of materials for construction and fuel including wood, biofuels and plant oils that are directly derived from wild and cultivated plant species.
Fresh water: Ecosystems play a vital role in the global hydrological cycle, as they regulate the flow and purification of water. Vegetation and forests influence the quantity of water available locally.
Medicinal resources: Ecosystems and biodiversity provide many plants used as traditional medicines as well as providing the raw materials for the pharmaceutical industry. All ecosystems are a potential source of medicines.
Regulating Services are the services that ecosystems provide by acting as regulators eg. regulating the quality of air and soil or by providing flood and disease control.
Local climate and air quality: Trees provide shade whilst forests influence rainfall and water availability both locally and regionally. Trees or other plants also play an important role in regulating air quality by removing pollutants from the atmosphere.
Carbon sequestration and storage: Ecosystems regulate the global climate by storing and sequestering greenhouse gases. As trees and plants grow, they remove carbon dioxide from the atmosphere and effectively lock it away in their tissues. In this way forest ecosystems are carbon stores. Biodiversity also plays an important role by improving the capacity of ecosystems to adapt to the effects of climate change.
Moderation of extreme events: Extreme weather events or natural hazards include floods, storms, tsunamis, avalanches and landslides. Ecosystems and living organisms create buffers against natural disasters, thereby preventing possible damage. For example, wetlands can soak up flood water whilst trees can stabilize slopes. Coral reefs and mangroves help protect coastlines from storm damage.
Waste-water treatment: Ecosystems such as wetlands filter both human and animal waste and act as a natural buffer to the surrounding environment. Through the biological activity of microorganisms in the soil, most waste is broken down. Thereby pathogens (disease causing microbes) are eliminated, and the level of nutrients and pollution is reduced.
Erosion prevention and maintenance of soil fertility: Soil erosion is a key factor in the process of land degradation and desertification. Vegetation cover provides a vital regulating service by preventing soil erosion. Soil fertility is essential for plant growth and agriculture and well functioning ecosystems supply the soil with nutrients required to support plant growth.
Pollination: Insects and wind pollinate plants and trees which is essential for the development of fruits, vegetables and seeds. Animal pollination is an ecosystem service mainly provided by insects but also by some birds and bats. Some 87 out of the 115 leading global food crops depend upon animal pollination including important cash crops such as cocoa and coffee (Klein et al. 2007).
Biological control: Ecosystems are important for regulating pests and vector borne diseases that attack plants, animals and people. Ecosystems regulate pests and diseases through the activities of predators and parasites. Birds, bats, flies, wasps, frogs and fungi all act as natural controls.
Habitats for species: Habitats provide everything that an individual plant or animal needs to survive: food; water; and shelter. Each ecosystem provides different habitats that can be essential for a species’ lifecycle. Migratory species including birds, fish, mammals and insects all depend upon different ecosystems during their movements.
Maintenance of genetic diversity: Genetic diversity is the variety of genes between and within species populations. Genetic diversity distinguishes different breeds or races from each other thus providing the basis for locally well-adapted cultivars and a gene pool for further developing commercial crops and livestock. Some habitats have an exceptionally high number of species which makes them more genetically diverse than others and are known as ‘biodiversity hotspots
- Recreation and mental and physical health: Walking and playing sports in green space is not only a good form of physical exercise but also lets people relax. The role that green space plays in maintaining mental and physical health is increasingly being recognized, despite difficulties of measurement.
- Tourism: Ecosystems and biodiversity play an important role for many kinds of tourism which in turn provides considerable economic benefits and is a vital source of income for many countries. In 2008 global earnings from tourism summed up to US$ 944 billion. Cultural and eco-tourism can also educate people about the importance of biological diversity.
- Aesthetic appreciation and inspiration for culture, art and design: Language, knowledge and the natural environment have been intimately related throughout human history. Biodiversity, ecosystems and natural landscapes have been the source of inspiration for much of our art, culture and increasingly for science.
- Spiritual experience and sense of place: In many parts of the world natural features such as specific forests, caves or mountains are considered sacred or have a religious meaning. Nature is a common element of all major religions and traditional knowledge, and associated customs are important for creating a sense of belonging.
Biomes are very large ecological areas on the earth’s surface, with fauna and flora (animals and plants) adapting to their environment. Biomes are often defined by abiotic factors such as climate, relief, geology, soils and vegetation. A biome is NOT an ecosystem, although in a way it can look like a massive ecosystem. If you take a closer look, you will notice that plants or animals in any of the biomes have special adaptations that make it possible for them to exist in that area. You may find many units of ecosystems within one biome.
There are five major categories of biomes on earth. In these five, there are many sub-biomes, under which are many more well defined ecosystems.
Difference between Biosphere and Ecosphere
Biosphere, Ecosphere and Gaia are used names of the global ecosystem. But each global ecosystem has its own or more meaning individually. The global ecosystem is natural cycles of interdependent organisms which share’s and functions together in the same habitat. Ecosystems usually form a number of food webs.
Ecosystems relate to soil, plants, animals, chemicals and rocks amongst others of the planet. For example when we think of nature we think of living things such as planets and animals, the biotic components of an ecosystem include all the living things in an area.
Ecozones are a method of dividing up the Earth’s surface. Each ecozone is a large area that contains a number of habitats, which are linked by the evolutionary history of the animals and plants within them. For instance one ecozone is Australasia, because its marsupials evolved in isolation to mammals in the rest of the world.
Similarities / Differences between Biomes and Ecozones
A biome is a major geographical area of ecologically similar communities of plants, animals, and soil organisms, often referred to as ecosystems. Biomes are defined based on factors such as plant structures (such as trees, shrubs, and grasses), leaf types (such as broadleaf and needleleaf), plant spacing (forest, woodland, savanna), and other factors like climate. Unlike ecozones, biomes are not defined by genetic, taxonomic, or historical similarities. Biomes are often identified with particular patterns of ecological succession and climax vegetation.
The biodiversity characteristic of each biome, especially the diversity of fauna and subdominant plant forms, is a function of abiotic factors and the biomass productivity of the dominant vegetation. Species diversity tends to be higher in terrestrial biomes with higher net primary productivity,eat out moisture availability, and temperature.