Bio 108 Lecture2

Bio 108 Lecture2 - 9/29/2010 1 Lecture 2 Lecture 2....

Info iconThis preview shows pages 1–5. 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
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 9/29/2010 1 Lecture 2 Lecture 2. Lamarckism vs. Plasticity. The Evolutionary Synthesis Adaptive Phenotypic Plasticity Organisms suddenly appear adapted to a different environmen different environment Selection has acted to develop mechanisms that allow organisms to exhibit a range of phenotype so they are adapted to regularly encountered environmental variation variation. As a result, the environment affects gene expression, not the genes themselves. 9/29/2010 2 What is Phenotypic Plasticity.. The ability of a genotype to exhibit a different phenotype in response to different environmental conditions. The response may be quantitative (differ on a measured scale) or qualitative on a measured scale) or qualitative (differ in kind) Plasticity can be... Quantitative size depends on nutrition poor nutrition => smaller body plants in low light become etiolated in low light Qualitative different shapes of leaves in plants (often different parts of the same plant) e.g. light vs. shade or underwater vs. floating Polyphenism - Different environmentally determined morphs (morphological types) e.g. Locusts. 9/29/2010 3 Locusta migratoria & Schistocerca gregaria Locust plague cryptic green coloration obvious coloration gregarious solitary sedentary constantly moving S. gregaria nymphs What causes this PHASE shift 1. Contact between juveniles changes hormone levels that in turn changes gene expression 2. Effect of Maternal Environment: Mothers experiencing high density secrete a chemical signal that affects gene expression in the eggs 9/29/2010 4 How does this differ from the...
View Full Document

This note was uploaded on 10/28/2010 for the course BIOL 108 taught by Professor Nunney during the Spring '10 term at UC Riverside.

Page1 / 14

Bio 108 Lecture2 - 9/29/2010 1 Lecture 2 Lecture 2....

This preview shows document pages 1 - 5. Sign up to view the full document.

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