Ecological interactions (article) | Ecology | Khan Academy
A fundamental concept in ecology is the competitive exclusion principle. They need adequate sunlight, soil nutrients, and fresh water to survive. For example, when sunlight is the limiting factor, some forest trees grow rapidly to tower over. Competitive relationships in a biological community can help the fittest to survive, The antelope, for example, is not the lion's only prey. Plants also compete for space, nutrients and resources such as water and sunlight. For example, plants often compete for access to a limited supply of nutrients, water, A BIOME IS AN ECOSYSTEM, SUCH AS A TUNDRA, THAT EXTENDS may change the competitive relationships within it, leading to interesting results .
For example, when sunlight is the limiting factor, some forest trees grow rapidly to tower over their competitors and absorb the most sunlight, others channel their energy into producing many seeds and attempting to spread them so that they increase the chances of their offspring landing in a well-lit area. Plants have developed all kinds of competitive strategies from storing nutrients to becoming parasites to developing disease resistance.
How to Avoid Competition- Isolate Yourself Nature is am amazing beast; it has mechanisms in place to allow species to exist in the same place at the same time using the similar resources. This is the beauty of niche separation and is the answer to the competitive exclusion principle. Different species have different life requirements, eat different foods, live in different habitats, and behave differently, all in the name of sharing resources. Sometimes, however, there is just no way around it, organisms have to share the same resources, and in this instance, nature has the uncanny ability to adapt.
Geographic Isolation One method of isolation is geographic isolation- not being in the same place at the same time. Animals that are geographically separated have a better chance of obtaining the resources they need. This isolation can occur through animals having different geographic distributions or by participating in seasonal migrations. Geographic separators might be an expanse of land, a mountain range, a body of water, or an elevation gradient.
Behavioral Isolation This occurs when animals have contradictory behaviors that prevent them from competing with each other. For example, by day, birds rule the air. They forage, maintain territories, reproduce, and compete with each other for the best available resources. By night, however, bats rule the roost. Come dusk there is a taxonomic tango when the diurnal active by day organisms retire for the evening and the nocturnal active by night organisms commence their daily follies.
By the cover of night nocturnal organisms avoid competitive interactions with their diurnal counterparts. In some ecosystems, the nightly taxonomic exchange is quite the spectacle. Certain night-blooming flowers open their blossoms to be pollinated by bats.
Insects emerge to forage after spending the day avoiding hungry birds. Foraging habits are another way that organisms can avert competing with each other. Take raptors for example. A red-tailed hawk is a generalist predator; they eat anything from rodents to reptiles to other birds. They are good competitors with other birds of prey because they consume a wide variety of prey so their options are many. Specialist predators, however, like the osprey, which eats strictly fish, are limited in their prey selection as well as their geographic range because they have to live in areas where their prey resides.
Take two similar animals then that inhabit the same geographic area and eat the same type of food…what then? Herbivorous rhinos deal with this conundrum by consuming different parts of plants.
White rhinos have flat, wide lips for grazing grasses while black rhinos have pointed, dexterous lips for browsing shrubs. Mechanical Isolation The lip morphology of rhinos is an evolutionary expression of a behavioral trait that separated rhinos long ago. Today there are many animals that have morphological differences that directly allow them to avoid competition with other organisms.
Sometimes isolation mechanisms influence each other, adding another impediment to competition. Organisms that have been geographically separated for long periods of time can evolve morphological and behavioral changes that prevent them from breeding with each other.
All these methods of isolation are changes that have occurred over many generations. Organisms have evolved over time to avoid competition and the changes have become incorporated in their life histories. The most awesome thing about evolution is that it never stops! As the environment changes and new stressors are added to an ecosystem, that pressure influences organisms to change, thus making them better competitors.
Competition plays a very important role in ecology and evolution. The best competitors are the ones who survive and get to pass on their genes.
Their progeny offspring will have an increased chance of survival because their parents out-competed their conspecifics. The best competitors have the best fitness, which is a measure of the genes that are passed on to succeeding generations. So the best competitors are the best survivors, which have more offspring, which means that more competitive genes are perpetuated in the gene pool. It is important to note that these changes occur over very long periods of time and the life history characteristics of organisms we see today are the results of changes that happened over millennia.
The Trade Off These rewards are not without consequence. Sometimes being a good competitor in one area means that you are lacking in another. Take Australian lyrebirds for example.
They have long, beautiful tail plumes as ornaments to attract female mates. The longer, more colorful their feathers are, the better competitors they are among other males, but this also means that they are more conspicuous. A colorful bird with long, elaborate feathers is not hard to miss, particularly when he is dancing and calling to attract a mate.
The very characteristics that make him a good competitor among his male counterparts are also a detriment to him as they also attract potential predators. The question then becomes…is advertising for female mates worth the risk of being discovered by a predator? What do you think? By maintaining the community they resist invasion by other potential competitors.
Communities can be made up of a single species, or there can be mixed species colonies. Mixed seabird colony- great crested terns and brown boobies Kia Island, Fiji Competition as a Regulator When two organisms or populations compete with each other, whether it be directly or indirectly, one of several outcomes can be expected. If, however, the competition event is spread over time and the losing animal has time to respond and recover, they may relocate to another geographic area emigrate.
If the losing organism is not displaced, it may change its behavior or requirements to utilize different resources so that it is no longer in competition with its opponent.
- Competition (biology)
- Ecological interactions
Creatures on the tundra face little stress from competition, but a great deal of stress in the form of very short growing seasons, thin soil, limited ground cover, low average temperatures and rainfall, high winds, and so on. If the density of individual plants of the tundra is decreased experimentally by thinning, the residual plants do not thrive as a result, as they might in a less harsh climate. In the case of the tundra, it is not competition that constrains their productivity, and therefore the reduction of potential competition does little to improve conditions for the organisms that survive.
It is interesting to observe what happens in a tundra environment if the intensity of environmental stress is artificially and experimentally alleviated by enclosing an area under a greenhouse and by fertilizing it with nutrients. Such experiments have been performed, and the results are fascinating: Diamond showed that local biological communities are among the leading determinants of the success or failure of human civilizations.
The book had its beginnings, he wrote, during his many years of work with the native peoples of New Guinea. One day, a young man put a simple question to him: The question may have been simple, but the answer was not obvious.
As a scientist, Diamond refused to give an answer informed by the politics of the Left or Right, which might have blamed the problem, respectively, on western exploitation or on the failures of the New Guineans themselves. Instead, he approached it as a question of environment, and the result was his thought-provoking analysis, contained in Guns, Germs, and Steel. As Diamond showed, the places where agriculture was born were precisely those blessed with favorable climate, soil, and indigenous plant and animal life.
Of course, it is no accident that civilization was born in the societies where agriculture first developed.
Competition - Untamed Science
Before a civilization can evolve, a society must become settled, and for that to happen, it must have agriculture. Agriculture came into existence in four places during a period from about to B. In roughly chronological order, these locations were Mesopotamia, Egypt, India, and China.
All were destined to emerge as civilizations, complete with written language, cities, and organized governments, between about and B. In the New World, by contrast, agriculture appeared much later and in a much smaller way.
Biological Communities - Real-life applications
The same was true of Africa and the Pacific Islands. In seeking to find the reasons why this happened, Diamond noted a number of factors, including geography. The agricultural areas of the Old World were stretched across a wide area at similar latitudes. This meant that the climates were not significantly different and would support agricultural exchanges, such as the spread of wheat and other crops from one region or ecosystem to another.