bieb132.lecture_2_sept_28

bieb132.lecture_2_sept_28 - BIEB 132: Lecture 2 Adaptations...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: BIEB 132: Lecture 2 Adaptations to environmental temperature and salinity Required reading : Levinton, Marine Biology (3rd ed) Chapter 4 Recommended reading: Barry et al. 1995. Climate-related, long-term faunal changes in a California rocky intertidal community. Science 267: 672 -675 Adaptations of marine organisms to changes in temperature and salinity • As terrestrial organisms, we are used to rapid changes in temperature and humidity. • Such changes are not characteristic of aquatic habitats, especially in the ocean. • As a consequence, many marine organisms have narrow physiological tolerances. View of deep sea North Pacifc South Atlantic ~ 2 o C ~ 2 o C Intertidal zone ~ 0-35+ o C One of the exceptions: Some marine habitats show great changes in temperature on various time scales • Surface waters in some places- seasonal change • Gulf of Mexico • Altantic coast • Intertidal zone - diurnal change • Tidepools • Mudflats There are also many places where there is seasonal change in surface waters FIG. 4.1 (a) Acclimation response of oxygen consumption following a change of temperature. (b) Response of body fluid salt content to environmental salinity variation of a regulator and of a conformer. Organismal Responses to Environmental Change • Immediate response • At steady-state “Scope for growth” = Energy assimilated - energy needed for (food) maintenance metabolism High scope for growth --> growth and reproduction can occur Negative scope for growth --> animal is consuming reserves and will ultimately die when reserves are depleted FIG. 4.2 Scope for growth of a mussel under conditions of high, medium, and low food rations and varying temperature. Note that, as temperature increases or food decreases beyond a certain point, scope for growth, in terms of energy balance, falls below zero. • Higher temperatures result in higher metabolic rates Temperature tolerance Often differs among co-occurring species Often differs geographically within species (closer to thermal limits at geographic extremes) -differences can be genetic -often due to acclimation FIG. 4.3 One can measure differences in temperature tolerance by exposing groups of animals to different temperatures and measuring mortality after 24 hours. The LD 50 is the temperature at which 50 percent cumulative mortality occurs. In this example comparing eastern U.S. arthropods, a mysid shrimp, Neomysis americana , was taken from near the southern end of its geographic range. It proves to be less tolerant of high temperature than the mud crab Rhithropanopeus harrisii . (Modified from Mihursky and Kennedy, 1967.) On a seasonal basis, many organisms show adjustments of their metabolic rates (otherwise the rate may be too high in summer or too low in winter)....
View Full Document

This note was uploaded on 10/18/2010 for the course BIEB BIEB 132 taught by Professor Hastings during the Fall '09 term at UCSD.

Page1 / 59

bieb132.lecture_2_sept_28 - BIEB 132: Lecture 2 Adaptations...

This preview shows document pages 1 - 11. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online