three factors that limit dispersal of a species?
467164
Physical Boundaries\nNot enough recources (food)\nPredation
527843
1. competition, cooperation or parasitism\n\n2. a. secure physical security [generally most organisms can t go beyond that]\nb. look for food\nc. look for shelter\nd. look for mating\ne. protect children [or whatever they are called]\nif any of the points there are not secured, then go back to it.
1067028
Try a rough DNA isolation, some things u need are detergent, lemons, and a sample like onion.\n\nSimple diffusion experiments with onions, salt, water, etc..
241874
There are more than two models for speciation mechanisms. \nProbably you're referring to \n**allopatric (allo= other + patric = fatherland) speciation, in which a population (of a single species) splits in subpopulations (due to dispersal of part of the population, a geologic event that fragments the original geographical range, etc.). Each of the subpopulations then continues to evolve separately and eventually they may develop reproductive isolation mechanisms, thus becoming distinct species. \nand \n**sympatric (syn= united + fatherland) model, the differentiation of a subgroup of the population occurs within the original geographical range of the source population.\n\nThe thing is that many speciation mechanisms have been proposed, according to different criteria. The two that I have VERY ROUGHLY described above are GEOGRAPHIC models, based on the spatial location of the speciating populations. Others are based on the time it takes for speciation to occur (gradual vs instantaneous), or the mechanisms entailed (polyploidy, hybridization, gradual differentiation, etc).\n\nMore on speciation with examples:\nhttp://users.rcn.com/jkimball.ma.ultranet/BiologyPages/S/Speciation.html\nhttp://www.mun.ca/biology/scarr/Speciation_models.htm
889798
Losing any plant can drastically affect the local environment.  Loss of the phlox (which grows on sandy soil) is bound to have serious erosion consequenses as the roots of the phlox bind the soil together.  Insects will lose a source of nectar and so the food chain will suffer further up.  \nYou may find the site belwo of interest...;
259928
little or no genetic variation, which is considered a detriment to the organism. It also means that it only take one to tango, so if the population is spread out, the species can still propogate itself. There was this great study done with minnows. They lived ina stream that would dry up into little pools every season. The fish were asexual in the dry season and sexual when they could find a mate.
247868
Not only biologists but everybody must feel concerned about the vanishing species on earth.This is  because nobody lives in isolation.We are all ( The plants,animals and man) related and dependent upon each other.)\n With every extinction an important link in the life on the earth is broken and gone. It has a cascading effect.\n In Australia, with the disappearance of Dodo ( A bird since extinct) the trees that were dependent on Dodo for germination of their seeds also disappeared. It was established that the seeds must pass through the digestive system of the bird before germination as the hard cover used to get digested by the bird.Scores of insects and bees bring about pollination in plants.Disappearance of these bees due to indiscriminate use of the pesticides will undoubtedly affects those plants.\nLife on this planet is like an intricate web, damage to any of its part will destroy the web and even man will not be spared.
489172
1- large amount of offspring in shorter time than K selected species.\n2- Early reproduction \n3- low biomass\n3- short lifespan\n\nBacteria, mice, insects... they're all r-selected.
677256
I don't really know.... my guesses would be regulating the fish population. I think a negative effect might be that fact that because they're an endangered creature wherever they build their nests, they can't be moved regardless of how inconvienet it is to people.
559563
1)water\n2)sun light\n3)Mineral nutrients\n4)Oxygen\n5)CO2\n6)Optimum Temperature\n7)Less Competition\n8)Ecological adaptations\n9)Soil or good substratum\n10)Role in local ecosystem
1046775
this question's kind of too big for a full answer on yahoo answers... but i would suggest you start with wikipedia and then follow links to the bits and pieces that interest you. (e.g. looking up a particular species that you want to use as an example). there are heaps of reasons birds migrate--seasonality of food source, mating, nesting site being overly far from a constant food source, etc... really, just start with wiki to get a basis and then hunt down the specifics. there are heaps of birdwatchers sites which will have nice pix on them too if you google them. good luck.
226331
If you have the book and the chapter reference, look these up:\n- ecological niche\n- intraspecific competition\n- resource partitioning\n- competitive exclusion\n\nEverything will be clearer then.
1078705
Where is it that you live?? Maybe loss of habitat in your area has caused them to leave for better places where more food can be found....if there was a swamp in your area that was filled in it could cause the insect population to drop and since insects are thier food of choice maybe there isnt enough anymore. I dont think that any type of animal can be banned from living where it wants but I am fairly certain that human interference is probably what caused them to leave the area in which you live.
974197
I asked that question, and there is no known mechanism. There is however a mechanism that keeps different species from being able to interbreed.
554417
1. Preserve their native habitats (that means preserving enough land for the space the large animals of the area need) For example large cats are estimated to need a roaming area of 100 square miles.  \n2. Stop the hunting of the endangered animal, by men and introduced predator species.\n3. Limit the number of competitors for the same resources of the endangered animal.\n4.  Find ways to improve genetic diversity in limited populations.
35811
1) Genetic variation among members of a population\n2) Inheritance of characteristics (or variations)\n3) Natural selection (survival of the fittest)\n4) Time
715107
The same as everywhere else.\n\nHigher wind speeds disperse pollutants.  Wind direction determines where pollutants go.