# Enlighten Theses

**Source**: https://theses.gla.ac.uk/7794/
**Parent**: https://theses.gla.ac.uk/view/subjects/QH.html

- [Skip to main content](#mainpage)
- [Accessibility information](http://www.gla.ac.uk/about/accessibility/)

Site navigation

- [Study](http://www.gla.ac.uk/study/)
- [Research](http://www.gla.ac.uk/research/)
- [About us](http://www.gla.ac.uk/about/)
- [Student life](http://www.gla.ac.uk/studentlife/)
- [Alumni](http://www.gla.ac.uk/alumni/)
- [Support us](http://www.gla.ac.uk/about/givingtoglasgow/)
- [Contact](http://www.gla.ac.uk/about/contact/)

Site tools

A-Z Lists

- [Subjects A-Z](http://www.gla.ac.uk/subjects/)
- [Staff A-Z](http://www.gla.ac.uk/stafflist/)
- [Academic units A-Z](http://www.gla.ac.uk/academic/)

- [Home](http://www.glasgow.ac.uk)
- [Enlighten](http://www.glasgow.ac.uk/services/enlighten)
- [Theses](http://theses.gla.ac.uk)

# [Enlighten Theses](http://theses.gla.ac.uk)

- [About](http://theses.gla.ac.uk/information.html)
- [Latest Additions](https://theses.gla.ac.uk/cgi/latest)
- [Search](https://theses.gla.ac.uk/cgi/search/advanced)
- [Browse](http://theses.gla.ac.uk/view/)
  - [Browse by
    Year](http://theses.gla.ac.uk/view/year/)
  - [Browse by
    Subject](http://theses.gla.ac.uk/view/subjects/)
  - [Browse by
    College/School](http://theses.gla.ac.uk/view/divisions/)
  - [Browse by
    Author](http://theses.gla.ac.uk/view/creators/)
  - [Browse by
    Funder](http://theses.gla.ac.uk/view/funder/)
- [ORCID](https://www.gla.ac.uk/myglasgow/research/managingyourpublications/publicationsandresearchreputation/identifiers/orcid/)
- [My Thesis](#)
  - [Login (Library staff only)](https://theses.gla.ac.uk/cgi/users/home)

In this section

# The consequences of phenotypic plasticity on postglacial fishes

Hooker, Oliver Edward
(2016)
*The consequences of phenotypic plasticity on postglacial fishes.*
PhD thesis, University of Glasgow.

Full text available as:

|  |  |
| --- | --- |
|  | PDF   [Download (3MB)](https://theses.gla.ac.uk/7794/1/2016HookerPhD.pdf) |

Printed Thesis Information: <https://eleanor.lib.gla.ac.uk/record=b3249368>

## Abstract

Phenotypic differences within a species significantly contribute to the variation we see among plants and animals. Plasticity as a concept helps us to understand some of this variation. Phenotypic plasticity plays a significant role in multiple ecological and evolutionary processes. Because plasticity can be driven by the environment it is more likely to produce beneficial alternative phenotypes than rare and often deleterious genetic mutations. Furthermore, differences in phenotypes that arise in response to the environment can affect multiple individuals from the same population (or entire populations) simultaneously and are therefore of greater evolutionary significance. This allows similar, beneficial alternative phenotypes to increase quickly within a single generation and allow new environments to produce and select for new phenotypes instantly. The direction of the present thesis is to increase our understanding of how phenotypic plasticity, coupled with contrasting environmental conditions, can produce alternative phenotypes within a population. Plasticity provides a source of variation for natural selection to act upon, and may lead to genetic isolation as a by-product. For example, there are multiple cases of polymorphic populations of fish, where groups belonging to multiple isolated gene pools, have arisen in sympatry. Here it is shown that although plasticity is important in sympatric speciation events, plasticity alone is not responsible for the frequency in which sympatric polymorphic populations occur. The most frequently observed differences among sympatric polymorphic populations are morphological differences associated with parts of the anatomy used in the detection, handling and capture of prey. Moreover, it is shown here that there are physiological effects associated with foraging on alternative prey that may significantly contribute towards ecological speciation. It is also shown in this study that anthropogenic abiotic factors can disrupt developmental processes during early ontogeny, significantly influencing morphology, and therefore having ecological consequences. Phenotypic structuring in postglacial fish is most frequently based around a divergence towards either pelagic or littoral benthic foraging specialisms. Divergences that deviate from this pattern are of greater scientific interest as they increase our understanding of how evolutionary processes and selection pressures work. Here we describe a rare divergence not based around the typical pelagic/littoral benthic foraging specialisms. Finally, in this study, the effectiveness of local level conservation policy shows that species of fish which are highly variable in their life history strategies are harder to effectively manage and often poorly represented at a local level.

|  |  |
| --- | --- |
| Item Type: | Thesis (PhD) |
| Qualification Level: | Doctoral |
| Keywords: | Plasticity, evolution, speciation, phenotype, phenotypic plasticity, morphology, physiology, postglacial fishes. |
| Subjects: | [Q Science](https://theses.gla.ac.uk/view/subjects/Q.html) > [Q Science (General)](https://theses.gla.ac.uk/view/subjects/Q1.html) [Q Science](https://theses.gla.ac.uk/view/subjects/Q.html) > [QH Natural history](https://theses.gla.ac.uk/view/subjects/QH.html) [Q Science](https://theses.gla.ac.uk/view/subjects/Q.html) > [QH Natural history](https://theses.gla.ac.uk/view/subjects/QH.html) > [QH301 Biology](https://theses.gla.ac.uk/view/subjects/QH301.html) [Q Science](https://theses.gla.ac.uk/view/subjects/Q.html) > [QL Zoology](https://theses.gla.ac.uk/view/subjects/QL.html) |
| Colleges/Schools: | [College of Medical Veterinary and Life Sciences](https://theses.gla.ac.uk/view/divisions/20000000/) > [Institute of Biodiversity Animal Health and Comparative Medicine](https://theses.gla.ac.uk/view/divisions/25000000/) > [Transmission Dynamics](https://theses.gla.ac.uk/view/divisions/25001000/) |
| Supervisor's Name: | Adams, Prof. Colin E. |
| Date of Award: | 2016 |
| Depositing User: | [Mr Oliver E Hooker](https://theses.gla.ac.uk/cgi/users/home?screen=User::View&userid=14397) |
| Unique ID: | glathesis:2016-7794 |
| Copyright: | Copyright of this thesis is held by the author. |
| Date Deposited: | 16 Dec 2016 11:07 |
| Last Modified: | 09 Jan 2017 13:22 |
| URI: | <https://theses.gla.ac.uk/id/eprint/7794> |

### Actions (login required)

|  |  |
| --- | --- |
|  | View Item |

### Downloads

Downloads per month over past year

Tools

[Tools](#)

[Tools](#)

RDF+XML
RDF+N-Triples
JSON
RefWorks
Dublin Core
Atom
Simple Metadata
Refer
METS
HTML Citation
ASCII Citation
OpenURL ContextObject
EndNote
OpenURL ContextObject in Span
MODS
MPEG-21 DIDL
EP3 XML
Data Cite XML
Reference Manager
RDF+N3
Multiline CSV

\

[Back to top](#)

## [Library](http://www.gla.ac.uk/services/library/)

- [Contact us](http://www.gla.ac.uk/services/library/contact/)

The University of Glasgow is a registered Scottish charity: Registration Number SC004401