Cave Community

the cave is always dark and so laxs green plants bacteria and fungi are the only plants cave animals feed outside the cave eat things brought into the cave or prey on other cave dwellers cave organisms are related to those above ground but are adapted to life in darkness I'm a biologist interested in cave life these are some of the specimens that we collected from a cave on a recent field CP I also have notes on our observation caves like outer space offer many opportunities for further exploration thus our interest in the unknown extends downward to the inside of the Earth a cave is of particular interest to the biologists because it represents a very unusual and relatively unchanging physical environment in the depth of a cave there is constant Darkness the Cave's level of hum is usually close to that of saturation the temperature of the environment year round is approximately 55° it varies little due to the insulating effect of the rock there are no green plants here plant life in a Cave's total darkness is restricted to a few kinds of fungi and bacteria whose activity produces no new food energy nevertheless life has successfully penetrated the isolation of the deep cave in many places and at many times a variety of living things entered cave habitats some perished others found them suitable for survival one result of continued isolation has been the development of new subspecies and species this is known as speciation species peculiar to different cave systems are evolving like this ireless cave Beetle here is the preserved specimen of that ey cave Beetle for comparison we also have a surface ground beetle to which it is closely related this one was collected above the ground in the same area in a number of unconnected caves in the area we have found different but related species all related to the same surface relative such evidence is the basis for this diagram new species or subspecies found in different caves of the same region have evolved from a common ancestor which once lived on the surface originally this ancestor went down into the caves of that locality this same thing occurs in other cave systems in many parts of the world in different regions of course different animals will be found it appears that it is the geographic isolation of unconnected cave systems that is primarily responsible for this speciation in cases like these two caves that are not connected by an underground passage the individuals cannot interbreed and in time two species are likely to develop but in caves like these two that are connected by an underground each the individuals of a species will form a single interbreeding population and will remain a single species in all cases however these creatures living in isolation underground are dependent upon energy from the surface World sometimes an occasional visitor such as a raccoon may bring in food from the outside more often surface waters wash in leaves and other organic matter the amount of water in a cave varies with the rainfall and is the most significant physical variable in the environment there are some animals such as the bats that live below the ground only part of the time they must return periodically to the surface where they feed on insects because they bring in food energy from outside the cave bass provide one of the most important links in feeding the rest of the cave population and extraordinary sonar apparatus using very high frequency sounds allows them to navigate in confined spaces and total darkness only the lower frequencies of the sounds made by bats are audible to human ears that excrement called guano is deposited in large quantities on the floors of many caves in these caves guano is one of the basic sources of food energy for those animals living entirely underground animals such as springtails isopods flatworms harvestmen and crickets a biologist is concerned particularly with those cave organisms whose evolutionary modifications make it impossible for them to live elsewhere chap among these modifications are loss of pigment and loss of functional eyes some species of blind cavefish have very sensitive pil on their heads and Jaws which apparently detect vibrations in the water in addition to reduction of eyes in pigment this cap crayfish has relatively longer and more sensitive antenni than related species with eyes and pigment that sometimes go into the cave this species of cave salamander has rudimentary eyes this suggests that it has become only partly adapted to Cave life ultimately it will probably become completely blind terrestrial organisms like the cave harvestmen are extremely sensitive to variations in temperature humidity and air currents the second pair of legs serves an antenna likee function to compensate for l five exploring the cave Community furthers our knowledge of the regressive and adaptive characteristics of cave life for example why is it that cave animals are predominantly white and blind we know that mutations resulting in the reduction of eyes and pigmentation occur throughout the animal kingdom in the surface world where protective coloring and are necessary for survival such forms are likely to be eliminated in The Cave however where pigmentation and sight are not needed such forms May survive mutation loss is quite regularly accompanied by the gain through mutation and natural selection of some compensatory trait such as this blind cray fishes relatively longer and more sensitive antenni this means that in certain environments the new form is actually better equipped for survival than the original form for the white and blind mutant a cave is a favorable environment if the roof of a cave Falls in so that the cave becomes lighted its special population will probably become extinct it is extremely unlikely that cave creatures could ever again adapt to surface environment the price of survival has been extreme specialization and regressive Evolution thus the study of cave life provides special Clues to the central questions of adaptation and evolution another important part of the study of cave life concern turns its food web as in every other community plants and animals of a cave are related to one another in a food web the ultimate source of energy is the sun green plants transform solar energy into a usable form bats crickets and certain other cave inhabitants leave the cave for food their droppings within the cave are subsequently eaten by some other cave organisms those that eat debris the detrius feeders as they are called are in turn eaten by Predators the cycle is further enlarged by the presence of debris carried into the cave by streams that animals from within the environment or visitors from outside Al contribute to the food web as an ecologist I am trying to learn more and more about how the cave environment affects the plants and animals living within it Research into this unusual biome provides data for understanding some of the mechanisms of the evolution of species it also reveals the ecological interactions that occur in a community without light