His original plan was to do field studies to demonstrate the economic value of biodiversity, but while working in the ecological theory lab at the University of Wisconsin, Gilman was introduced to mathematical biology and the myriad ecological and evolutionary questions researchers can investigate with mathematical tools.
The problems I work on are varied, and when one starts to get old it is time to move on to another. So, intellectually, it is really quite exciting," Gilman said. Gilman hopes that the results of his research will help scientists understand the two-way relationship between evolutionary and ecological processes in speciation, and perhaps ultimately aid conservationists and ecosystem managers interested in maintaining biodiversity and in preserving the function of ecosystems.
The National Institute for Mathematical and Biological Synthesis NIMBioS brings together researchers from around the world to collaborate across disciplinary boundaries to investigate solutions to basic and applied problems in the life sciences. Department of Homeland Security, and the U.
Investigating the Relationship Between Coevolution and Speciation Plants and animals are constantly evolving in response to other species with whom they interact, a process known as coevolution. These hollow thorns are the exclusive nest-site of some species of ant that drink the nectar. But the ants are not just taking advantage of the plant — they also defend their acacia plant against herbivores. This system is probably the product of coevolution: the plants would not have evolved hollow thorns or nectar pores unless their evolution had been affected by the ants, and the ants would not have evolved herbivore defense behaviors unless their evolution had been affected by the plants.
Learn more about coevolution in context: Biological warfare and the coevolutionary arms race , a case study. Misconceptions about natural selection. A case study of coevolution: squirrels, birds, and the pinecones they love. The ants even remove vines and plants from around the base of the tree, creating a bare patch on the soil. Plants of the bullshorn Acacia which have not been occupied by ant colonies are heavily attacked by herbivores and often have vines growing in the branches.
Related Acacia species lack hollow thorns and food bodies, and do not have specific associations with ants. They also have many cyanogenic glycosides in their leaves. This data strongly supports the idea that the bullshorn Acacia has evolved a close, mutualistic association with the ants in order to protect themselves from herbivores and also plant competitors.
It also supports the idea that the cyanogenic glycosides found in other species have a defensive role; a role which has been taken over by Pseudomyrmex in the bullshorn Acacia. Egg mimicry in Passiflora. Similarly, we have already given examples of egg-mimicry in Passiflora , which protects plants against species of Heliconius butterflies. Female Heliconius avoid laying eggs on plants already occupied by eggs, because first instar larvae of Heliconius are highly cannibalistic; the plants exploit this habit of Heliconius by creating fake yellow eggs as deciduous buds, stipule tips, or as part of the "extrafloral nectaries" on young leaves.
Clearly, the plant, whose defenses of cyanogenic glycosides, alkaloids, and a host of other secondary compounts, have been breached by Heliconius , has counterevolved new defenses against this genus.
Predators have obviously evolved to exploit their prey, with hunting ability being at a premium. Mammalian predators, for example, must be fast, strong and cunning enough to be able to catch their prey.
It is almost as obvious that prey have evolved to protect themselves from predators. They may have a variety of defenses:. Two of the most famous are figs and fig-wasps, and Yucca and Yucca moths Tegeticula. In both cases, the plant is completely dependent on its herbivore for pollination. The arrangement is therefore a tightly coevolved mutualism, in which the plant relies exclusively on the insect for pollination, and the insect relies exclusively on the plant for food.
In the case of the Yucca moth the mutualism has sometimes broken down, and some clades of the moth have reverted to a parasitic mode of life -- they oviposit in the plant, but do not pollinate -- the ancestral condition for the moths. These examples are interesting because they represent cases where mutualisms have become so specific that they almost rival the ancient prokaryotic mutualisms of mitochondria and chloroplasts with archaebacterial cells, to produce what we now know as eukaryotes.
It is an ecological principle Gause's principle that related species must differ in some part of their ecology. If two species have identical or nearly identical resources, competitive exclusion will result, and the less well adapted species will go extinct.
If this is true, and it probably is, the reverse should also occur. If a species colonizes an area where its competitors do not occur, then it may experience ecological release , and grow to very large population sizes. Not only that, the colonists may also experience disruptive selection, followed by speciation.
The process can be repeated for multiple species, which evolve apart from one other to form an adaptive radiation. Many examples of this principle are known in island colonists.
For example, we have already come across the Darwin's finches of the Galapagos islands, which have evolved into a whole range of seed-feeding and insectivorous forms. A similar, although much more diverse radiation occurs in the Hawaiian archipelago: the Hawaiian honeycreepers.
Sometimes, the islands are " ecological islands " rather than actual islands. A number of lakes in the North temperate zone were left behind during the retreat of the ice. These lakes have in the last 10, years been colonized by a variety of fish.
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