What Is A Selecting Agent In Biology
A selecting agent is any factor, environmental or otherwise, that affects fertility or mortality. Selecting agents include available food sources, local predators, and many other factors in or around a biosphere or individual.
An individual organism’s fertility is a very basic example of a selecting factor. If an organism cannot reproduce, or if its reproductive faculties are limited, it stands a greater change of having its unique genes peter out due to failure to reproduce. If an organism is highly fertile, then it stands a good chance of passing on its genes and thus its fertility.
Both a predator’s ability to hunt and a prey animal’s ability to avoid capture are selecting factors for the same reason. Other, more complex selecting factors include an organism’s ability to adapt to changing circumstances. These circumstances can include sudden shifts in climate, differing availability of food and the introduction of new species through forced migration or other means.
Natural selection ensures that in the absence of superabundance, only the most suited organisms will survive to reproduce. Moths that cannot disguise themselves to avoid predators will naturally be eliminated in an environment where they are forced to compete with camouflaged moths for resources and space.
Competition As An Ecological And Evolutionary Factor
Competition is a biological interaction among organisms of the same or different species associated with the need for a common resource that occurs in a limited supply relative to demand. In other words, competition occurs when the capability of the environment to supply resources is smaller than the potential biological requirement so that organisms interfere with each other. Plants, for example, often compete for access to a limited supply of nutrients, water, sunlight, and space.
Intraspecific competition occurs when individuals of the same species vie for access to essential resources, while interspecific competition occurs between different species. Stresses associated with competition are said to be symmetric if they involve organisms of similar size and/or abilities to utilize resources. Competition is asymmetric when there are substantial differences in these abilities, as occurs in the case of large trees interacting with plants of a forest understory.
Over long periods of time, competitive displacement may lead to evolutionary changes. This happens as species displaced to marginal environments evolve to become better adapted to those conditions, and they may eventually become new species. Competitive displacement is believed to be the primary force leading to the evolution of species swarms on isolated islands such as those of fruit flies and honeycreepers on the Hawaiian Islands and Darwin’s finches on the Galapagos Islands.
Competition Predation And Commensalism
Intraspecific competition occurs between red and purple sea urchins when resources are limited, such as food and habitat space. Within sea urchin barrens, high densities of sea urchins with scarce food resources make conditions optimal for competition. There is indirect evidence of intraspecific competition in purple sea urchins: size-frequency distributions show that 90% of the sea urchins in high-density sites are mid-size and small , while inside reserves where densities are low purple sea urchins are much larger . Interspecific competition also occurs between red and purple sea urchins in southern California . Schroeter found that red sea urchins are competitive dominants over purple sea urchins and use their long spines to actively fence purple sea urchins and exclude them from optimal habitats. Conversely, in Alaska, there is interspecific facilitation between red sea urchins and other congeners. Red sea urchins snag drift kelp with their long spines and provide defense against predatory sunflower sea stars . Little is known about interactions between red and purple sea urchins and the black sea urchin, Centrostephanus coronatus, in southern California .
Maria Byrne, Neil Andrew, in, 2013
Don’t Miss: What Does Algebra 2 Look Like
Indirect Competitors To Your Product And Market
This type of competition is observed when any small business is taking the customer away from you, by offering a product which does not exist in your portfolio. For example For bankers who are offering savings account only, indirect competition will be the stock , mutual funds and other savings accounts, where the customer invests his money instead of keeping it in savings account. So an executive responsible for selling savings accounts, will consider the above options as indirect competition.
In another example, a movie theatre will consider cable television and DVDs as its indirect competitors. This is because people might not be visiting theatres when they can watch the same movie at home.
In case of indirect competition, your strategy should be to give offers and conduct promotions so that the customer does not ignore you. In above savings account example, bankers can increase the percentage returns on opening savings account with them and thereby attract more customers. Similarly, to compete against the indirect competition or competitors the movie theatre can give promotional offers of free popcorn, show classic movies, or do some promotional activity to attract customers to the movie theatre. Such activities help in tackling the indirect type of competition.
Philosophical Issues In Population Genetics
Population genetics raises a number of interesting philosophicalissues. One such issue concerns the concept of the gene itself. As wehave seen, population genetics came into being in the 1920s and 1930s,long before the molecular structure of genes had been discovered. Inthese pre-molecular days, the gene was a theoretical entity,postulated in order to explain observed patterns of inheritance inbreeding experiments; what genes were made of, how they causedphenotypic changes, and how they were transmitted from parent tooffspring were not known. Today we do know the answers to thesequestions, thanks to the spectacular success of the molecular geneticsushered in by Watson and Crick’s discovery of the structure of DNA in1953. The gene has gone from being a theoretical entity to beingsomething that can actually be manipulated in the laboratory.
To conclude, it is unsurprising to find so much philosophicaldiscussion of population genetics given its centrality to evolutionarybiology, a science which has long attracted the attention ofphilosophers. The preceding discussion has focused on the mostprominent debates surrounding population genetics in the recentphilosophical literature; but in fact population genetics is relevant,at least indirectly, to virtually all of the topics traditionallydiscussed by philosophers of evolutionary biology.
Read Also: Geometry Lesson 1.7 Answers
Definition Of Competition In Biology
Competition in biology is a term that describes how living organisms directly or indirectly seek resources.
Competition can occur within a species or between different species. The many types of competition include everything from dogs fighting over a bone to rutting stags locking horns in a fight to the death.
Even microscopic bacteria vigorously compete through various mechanisms, such as exploiting a particular resource needed by competitors, or using metabolic functions to make the external environment unsuitable for other bacterial species.
Competition examples are ubiquitous in the natural world. Competitive invasive species such as stink bugs, khapra beetles, green ash borers, garlic mustard, Asian carp, zebra mussels and Asiatic beetles can decimate native species and severely disrupt the ecosystem. Scientists estimate that lichen produce more than 500 biochemical compounds that kill microbes, control light and suppress plant growth.
Competition in community ecology sustains life and strengthens the gene pool. Better competitors are more likely to survive and pass on their advantageous genetic traits to offspring. Whether a characteristic is favorable or unfavorable depends on environmental conditions.
For instance, hooves are better adaptations than toes for running across open grasslands.
Genetic Diseases In Humans
Many genetic diseases are increased in prevalence in human population due in part to the founder effect. Small populations of humans are either forcibly separated, or leave the larger genetic pool by choice. An example of the founder effect in this context is the higher incidence of fumarase deficiency in a population of members of a fundamentalist church. Practices of the church included endogamy, or marrying within the religion, and polygyny or the practice of taking several wives. What the founders of the religion did not know was that they carried a severely detrimental allele. The allele created a form of fumarase that was not function. This enzyme is needed to produce energy in the mitochondria. Without functional mitochondria, nearly all the cells in the body are affected. Children that receive a non-functional allele from both parents are severely disabled, with both developmental abnormalities and mental retardation. The founder effect has caused the population that practices this religion to experience a much higher incidence of this specific genetic condition.
Read Also: What Does Kw Mean In Chemistry
Competition Of The Herbivorous Kind
Competition isnt just a phenomenon in the animal world; plants compete with each other too. They need adequate sunlight, soil nutrients, and fresh water to survive. Though they are stationary, they still have ways of combating each other. Over time plants have evolved ingenious ways of procuring sunlight, attracting pollinators, and obtaining fresh water. They may take an offensive approach, responding to the competition head-on, or a defensive approach, making modifications to increase their chances of survival and reproduction. 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.
Types Of Competition And Examples
Competition in biology is tied to supply and demand. Individuals of a species will fiercely compete for whatever they need from the environment to survive and enjoy reproductive success.
Plants compete with each other for light exposure, temperature, humidity, pollinators, soil nutrients and growing space. Microbes compete for chemical substrates. Animals fight over territory, water, food, shelter and prospective mates.
Intraspecific competition involves direct competition between members of the same species. Competition can be keen within a species that shares an ecological niche because they demand identical resources. Competition is less of an issue when organisms live in different niches and use slightly different resources.
A common competition in biology example is the vocal and territorial male Northern cardinal that chases away other male cardinals interloping on its breeding grounds.
Interspecific competition occurs between members of different species that desire the same things, such as food, shelter and water. Direct competition is a type of struggle that involves species or organisms directly interacting with one another. Vultures and wolves both go after a fresh moose carcass, for instance.
Indirect competition does not involve direct confrontation; for example, non-migratory sparrows may build nests in bluebird houses before the migratory bluebirds return to their home from the previous season.
Also Check: Algebra Road Trip Project Answer Key
Population: Definition Attributes And Growth
In this article we will discuss about:- 1. Definition of Population 2. Population Attributes 3. Growth.
Definition of Population:
Population is a set of individuals of a particular species, which are found in a particular geographical area.
The population that occupies a very small area, is smaller in size, such a population is called local population. A group of such a closely related local population is called meta-population.
Population ecology is an important area of ecology because it links ecology to the population genetics and evolution. Natural selection operates at a levels of population.
A population has certain attributes that an individual organism does not have.
Some of them are given below:
Population Size or Density:
It is the number of individuals of a species per unit area or volume
Birth Rate :
It is the rate of production of new individuals per unit of population per unit time. For example, if in a pond, there are 20 lotus plants last year and through reproduction, 8 new plants are added, taking the current population to 28. Then, birth rate = 8/20 = 0.4 offspring per lotus per year.
Death Rate :
It is the rate of loss of individuals per unit time due to death or due to the different environmental changes, competition, predation, etc. For example, if individuals in a laboratory population of 40 fruit flies died during a specified time interval. Then, the death rate = 4/40 = 0.1 individuals per fruit fly per week.
The Competitive Exclusion Principle
To explain how species coexist, in 1934 G. F. Gause proposed the competitive exclusion principle: species cannot coexist if they have the same niche. The word “niche” refers to a species’ requirements for survival and reproduction. These requirements include both resources and proper habitat conditions . Gause reasoned that if two species had identical niches they would attempt to live in the exact same area and would compete for the exact same resources. If this happened, the species that was the best competitor would always exclude its competitors from that area. Therefore, species must at least have slightly different niches in order to coexist.
Joe Connell also tested Gause’s principle by studying barnacles that live on rocks along European coastlines. In 1961, Connell found that two barnacle species, Balanus and Chthamalus, can coexist because they differ in two traits: growth rate and vulnerability to desiccation . Balanus‘s growth is rapid, which allows it to smother and crush the slower-growing Chthamalus. Balanus, however, dies close to shore because it gets too dry during low tide. In contrast, Chthamalus tolerates these dry conditions. Consequently, even though Balanus is a better competitor for space, these barnacles coexist because Chthamalus can survive in areas that Balanus cannot survive. These and many other examples support the competitive exclusion principle: Species can only coexist if they have different niches.
Competition Definition In Biology
Competition is a relationship between organisms in which one is harmed when both are trying to use the same resource related to growth, reproduction, or survivability. Competition stems from the fact that resources are limited. There are simply not enough of some resources for all individuals to have equal access and supply. Competition can occur between organisms of the same species, or between members of different species.
Competition between species can either lead to the extinction of one of the species, or a decline in both of the species. However, this process can often be interrupted by environmental disturbances or evolution, which can change the rules of the game. Competition is often involved when species are limited in their range, often by direct competition from other organisms.
Within Species And Between Species
Competition can occur between individuals of the same species, called intraspecific competition, or between different species, called interspecific competition. Studies show that intraspecific competition can regulate population dynamics . This occurs because individuals become crowded as a population grows. Since individuals within a population require the same resources, crowding causes resources to become more limited. Some individuals eventually do not acquire enough resources and die or do not reproduce. This reduces population size and slows population growth.
Species also interact with other species that require the same resources. Consequently, interspecific competition can alter the sizes of many species’ populations at the same time. Experiments demonstrate that when species compete for a limited resource, one species eventually drives the populations of other species extinct. These experiments suggest that competing species cannot coexist because the best competitor will exclude all other competing species. Why then do communities seem to have many competing species that coexist in the same area?
You May Like: How To Calculate Half Life Chemistry
Customer Service And Satisfaction
After reading all the reasons above, just turn around and look at the customers. The customers would be happiest when they are buying from a segment where there is competition. And why wouldnt they be?
They are getting excellent service because if they are not served well, they will move over to the competitor. They are getting upgraded products, they are getting differentiated products, their social status is increasing, their requirements are getting fulfilled, and all this is happening at an excellent price.
Compare it with a monopolistic market and none of this will happen. The customer will never receive personal service, they will not receive the latest in technology, there wont be social status in acquiring such products, and the price would probably be a bomb too.
So one of the major benefits of competition, is that it makes customers positive towards buying a product. It makes them positive because they feel good being treated nice, being served well. And, you as a company will treat your customers nice, because otherwise they will go straight to the competitor. I know that i have done this several times.
So, overall, there are many benefits of Competition. I dont want to tell you that competition is too good for business. Because, if its over competition, and , it is probably affecting your business in a bad way .
Historical Background And Scientific Foundations
Competition in an ecological sense is the struggle between individuals for environmental resources. Resources include anything found in the environment that is necessary for growth and reproduction such as food, shelter, water, light, and substrate or territory. For individuals of the same species, resources can also include mates.
Resources are different from environmental conditions because resources have the potential to become scarce. Environmental conditions include components of the environment that affect the growth and reproduction of organisms but are shared identically among all members of an ecosystem. Such conditions include temperature, salinity, and pH.
A major factor affecting the availability of resources in an ecosystem is the density of individuals, or the number of organisms living in a certain area. If more individuals live in a certain area, resources are depleted more quickly and ecological competition for these limited resources intensifies. On the other hand, environmental conditions are unaffected by density. Regardless of the number of individuals living in an area, the air temperature or salinity of the water will be the same. Resources are therefore referred to as density dependent ecological factors, while environmental conditions are called density independent factors.
Read Also: What Is The Molecular Geometry Of Ccl4