Ch.53 - Community EcologyWorksheetSee all chapters
All Chapters
Ch.1 - Introduction to Biology
Ch.2 - Chemistry
Ch.3 - Water
Ch.4 - Carbon
Ch.5 - Biological Molecules
Ch.6 - Cells
Ch.7 - The Membrane
Ch.8 - Energy and Metabolism
Ch.9 - Respiration
Ch.10 - Photosynthesis
Ch.11 - Cell Signaling
Ch.12 - Cell Division
Ch.13 - Meiosis
Ch.14 - Mendelian Genetics
Ch.15 - Chromosomal Theory of Inheritance
Ch.16 - DNA Synthesis
Ch.17 - Gene Expression
Ch.18 - Regulation of Expression
Ch.19 - Viruses
Ch.20 - Biotechnology
Ch.21 - Genomics
Ch.22 - Development
Ch.23 - Evolution by Natural Selection
Ch.24 - Evolution of Populations
Ch.25 - Speciation
Ch.26 - History of Life on Earth
Ch.27 - Phylogeny
Ch.28 - Prokaryotes
Ch.29 - Protists
Ch.30 - Plants
Ch.31 - Fungi
Ch.32 - Overview of Animals
Ch.33 - Invertebrates
Ch.34 - Vertebrates
Ch.35 - Plant Anatomy
Ch.36 - Vascular Plant Transport
Ch.37 - Soil
Ch.38 - Plant Reproduction
Ch.39 - Plant Sensation and Response
Ch.40 - Animal Form and Function
Ch.41 - Digestive System
Ch.42 - Circulatory System
Ch.43 - Immune System
Ch.44 - Osmoregulation and Excretion
Ch.45 - Endocrine System
Ch.46 - Animal Reproduction
Ch.47 - Nervous System
Ch.48 - Sensory Systems
Ch.49 - Muscle Systems
Ch.50 - Ecology
Ch.51 - Animal Behavior
Ch.52 - Population Ecology
Ch.53 - Community Ecology
Ch.54 - Ecosystems
Ch.55 - Conservation Biology

Solution: In their 2008 paper, Hanifin, Brodie, and Brodie looked at the co evolution of a newts (Taricha spp., top picture) and one of their potential predators, the common garter snake (Thamnopis sirtalis). T

Problem

In their 2008 paper, Hanifin, Brodie, and Brodie looked at the co evolution of a newts (Taricha spp., top picture) and one of their potential predators, the common garter snake (Thamnopis sirtalis). The graph below shows the relationship between the amount of toxin in the skin of the newts and the garter snakes resistance to the toxin at a given location. The dashed line represents a reduction of 50% in the snake's health. Some locations may be considered co-evolutionary hot-spots, where reciprocal selection is strong Other locations are co-evolutionary cold spots, where the traits of one species don't match with the other and one species is "winning" the interaction. The letters on the graph represent 3 locations with snakes and newts.

a. In which of the three locations (if any) is co-evolution strong? In which locations (if any) is the snake "winning"? In which locations (if any) is the newt winning? Explain your reasoning. 

b. What might be an explanation for the dynamics occurring in population A, where the newt hasn't evolved toxicity and the snake hasn't evolved resistance. In other words, what might prevent a co-evolutionary arms race from occurring in this system?