Navigation Links
Yes, ecology shapes evolution, but guppies show reverse also true
Date:2/4/2010

TALLAHASSEE, Fla.--In the natural stream communities of Trinidad, guppy populations live close together, but evolve differently. Upstream, fewer predators mean more guppies but less food for each; they grow slowly and larger, reproduce later and less, and die older. Downstream, where predators thrive, guppies eat more, grow rapidly, stay small, reproduce quickly and die younger.

While it is clear to ecologists that an ecosystem shapes the evolution of animals living in it, population biology experts such as Joseph Travis of The Florida State University believe the reverse can also be true, making the relationship between evolution and ecology a model of reciprocity.

Now, he can prove it.

The evidence comes from an experiment in evolution that Travis designed with David N. Reznick of the University of California-Riverside and their fellow members of an interdisciplinary research team. Findings from the study expand the body of knowledge about the interactions between evolution and ecology by demonstrating that evolutionary adaptations can also act as triggers for a cascade of in-tandem changes to both ecosystem and animal.

In the experiment, led by Ronald D. Bassar of UC-Riverside, the team used artificial streams filled with the same spring water and insect larvae found in Trinidad's natural habitats to examine whether genetically distinct guppies from upstream or downstream had different effects on ecosystem processes. They compared the two types of guppies because earlier work showed that the little freshwater fish could evolve rapidly from a downstream "type" to an upstream "type."

The team found dramatic differences between the effects of each type of guppy on the nutrient cycles and overall productivity of the stream ecosystems. Travis said the results, which emerged very rapidly during the experiment, predict that the team's larger experiment introducing downstream guppies to upstream habitats will show that evolutionary change also will drive substantial changes in the ecosystem at the same time.

"Within just four weeks, the two types of guppies drove the parameters of the artificial streams in very different directions," said Travis, the dean of Florida State's College of Arts and Sciences and a distinguished professor in its Department of Biological Science.

The study is described in the Feb. 1, 2010, online edition of the journal PNAS (Proceedings of the National Academy of Sciences). It was funded by a five-year, $5 million grant from the National Science Foundation's Integrative Biological Research (FIBR) program.

It is essential that scientists better understand the evolution-ecology feedback loop and the surprising speed with which an ecosystem can be altered by adaptations in a species that populates it, said Travis, because so many animals and plants are evolving in response to ecosystem changes caused by humans. As an example, he points to the overharvesting of fish, which can cause some species to get smaller and die younger, which in turn could alter their ecosystem via a feedback loop that might eventually mean no fish to harvest at all.

"Evolution can be very fast," he said. "When our research team started this project, we already knew that downstream guppies mature earlier, make more and smaller babies, have less colorful males, and tend to be more carnivorous and less herbivorous than upstream guppies. Past work by David Reznick, our study's principal investigator, showed that if you take downstream guppies and introduce them to pools upstream with no guppies, the descendents of those founders will evolve to look like upstream guppies in a few dozen generations."

Travis and team hoped that their experiment would reveal whether the two types of guppies, upstream and downstream, were different enough that switching out one for the other would cause substantial changes in ecosystem processes. They collected guppies from the two different Trinidadian stream communities and placed them in the replicate, artificial streams that they'd built alongside the corresponding natural habitats.

"We also were careful to calibrate any effects against purely environmental differences, such as what one might see if we compared different, naturally occurring densities of guppies in both natural upstream and more crowded downstream conditions," Travis said. "So, our experiment simultaneously compared the ecological effects of guppies of each type in two densities, one double the other. That design enabled us to learn whether the changes we saw in the ecosystem processes were caused by the natural differences in guppy density or the differences in the guppy 'type.'"

"Type" mattered. For instance, because downstream guppies ate more insect larvae and less plant material, they excreted more nitrogen and less phosphorus.

"The combined effects of different grazing and different fertilization patterns served to change algal growth rates, detritus decay rates because guppies can eat the little animals that eat decaying leaves and the overall oxygen consumption rates in the ecosystem," Travis said.

"The evolutionary effects we documented are so large that an ecologist can no longer say, 'Sure, you evolutionary guys can show some effect from genetically based differences, but those effects are small in the big scheme of things.' Well, they aren't small. The changes generated by the new guppy species are at least as great as those found by doubling the density of existing guppies.

"We also show that the standard approach to theory in ecology and evolution, which is to say, 'Let's keep ecological variables constant and study evolution' or 'Let's keep evolutionary variables constant and study ecology,' isn't necessarily a good approximation for reality," Travis said. "We now know that evolutionary effects and ecological effects can unfold on comparable time scales."

Next, the researchers will examine how the feedback loop from the changed ecosystem shapes a new round of local adaptations in the relocated guppies.


'/>"/>

Contact: Joseph Travis
jtravis@fsu.edu
850-644-4404
Florida State University
Source:Eurekalert  

Related biology news :

1. Peter Reich, BBVA Foundation Frontiers of Knowledge Award in Ecology
2. Impact of eucalyptus plantations on the ecology of rivers
3. Ecology in organic ag: Combining farming, science
4. K-State receives more than $780,000 to fund graduate students studying ecology, evolution, genomics
5. NIH fellowship recipient to study disease ecology
6. Stimulus funding helps K-State bring undergrads to prairie for ecology, molecular biology research
7. Urban water ecology at the ESA annual meeting
8. Lohafex provides new insights on plankton ecology
9. Reversing ecology reveals ancient environments
10. Rise or fall of reef fish driven by both economy and ecology
11. Federal scientists recognized for contributions to knowledge of bird ecology and habitat
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Yes, ecology shapes evolution, but guppies show reverse also true
(Date:8/15/2017)... --  ivWatch LLC , a medical device company focused on improving ... of its ISO 13485 Certification, the global standard for medical device ... (ISO®). ... Monitoring device for the early detection of IV infiltrations. ... "This is an important milestone for ivWatch, as it ...
(Date:5/23/2017)...  Hunova, the first robotic gym for the rehabilitation and functional motor ... Genoa, Italy . The first 30 robots will be ... USA . The technology was developed and patented at the ... spin-off Movendo Technology thanks to a 10 million euro investment from entrepreneur ... ...
(Date:4/19/2017)... 19, 2017 The global military ... is marked by the presence of several large global ... by five major players - 3M Cogent, NEC Corporation, ... for nearly 61% of the global military biometric market ... the global military biometrics market boast global presence, which ...
Breaking Biology News(10 mins):
(Date:10/12/2017)... SARASOTA, FL (PRWEB) , ... ... ... Inc. (RPS®) today announces publication of a United States multicenter, prospective clinical ... single use, disposable, point-of-care diagnostic test capable of identifying clinically significant acute ...
(Date:10/11/2017)... YORBA LINDA, CA (PRWEB) , ... October 11, ... ... adapted to upregulate any gene in its endogenous context, enabling overexpression experiments and ... activation (CRISPRa) system with small RNA guides is transformative for performing systematic gain-of-function ...
(Date:10/11/2017)... LAGUNA HILLS, Calif. , Oct. 11, 2017  SkylineDx ... London (ICR) and University of Leeds ... to risk-stratify patients with multiple myeloma (MM), in a multi-centric ... The University of Leeds is the ... UK, and ICR will perform the testing services to include ...
(Date:10/10/2017)... ... October 10, 2017 , ... ... advancing targeted antibody-drug conjugate (ADC) therapeutics, today confirmed licensing rights that give ... Liposomal Nanoparticle), a technology developed in collaboration with Children’s Hospital Los Angeles ...
Breaking Biology Technology: