Section 19.1 Mechanisms of Evolution PDF

Integrating Concepts in Biology Chapter 16: Mechanisms of Evolution Section 19.1 How does selection act on individuals with variable characteristics? Copyright © 2015 by AM Campbell, LJ Heyer, CJ Paradise. All rights reserved. Biology Learning Objectives Exp...

Integrating Concepts in Biology Chapter 16: Mechanisms of Evolution Section 19.1 How does selection act on individuals with variable characteristics? Copyright © 2015 by AM Campbell, LJ Heyer, CJ Paradise. All rights reserved. Biology Learning Objectives Explain how the 5 tenets of natural selection influence individual organisms. Evaluate how the processes by which variation is generated in organisms affects natural selection. Explain how costs and benefits of performing different behaviors are assessed and how they relate to natural selection. Copyright © 2015 by AM Campbell, LJ Heyer, CJ Paradise. All rights reserved.  Things that you can observe in nature Question 1: Does every individual born (or hatched, etc.) survive to adulthood? Slide put together by Dr. Jeremy Gibson (2021)  Things that you can observe in nature Question 1: Does every individual born (or hatched, etc.) survive to adulthood? Slide put together by Dr. Jeremy Gibson (2021)  Things that you can observe in nature Question 1: Does every individual born (or hatched, etc.) survive to adulthood? Observation 1: NO – More offspring are produced than survive Slide put together by Dr. Jeremy Gibson (2021)  Things that you can observe in nature Question 2: Are all individuals in each generation the same? Slide put together by Dr. Jeremy Gibson (2021) https://a-z-animals.com/media/guppy-5.jpg  Things that you can observe in nature Question 2: Are all individuals in each generation the same? Slide put together by Dr. Jeremy Gibson (2021) https://a-z-animals.com/media/guppy-5.jpg  Things that you can observe in nature Question 2: Are all individuals in each generation the same? Observation 2: NO – individuals vary even if just slightly Slide put together by Dr. Jeremy Gibson (2021) https://a-z-animals.com/media/guppy-5.jpg  Things that you can observe in nature Question 3: Are some individuals better at gaining resources? Slide put together by Dr. Jeremy Gibson (2021) https://i.imgflip.com/1inhwe.gif  Things that you can observe in nature Question 3: Are some individuals better at gaining resources? Slide put together by Dr. Jeremy Gibson (2021) https://i.imgflip.com/1inhwe.gif  Things that you can observe in nature Question 3: Are some individuals better at gaining resources? Observation 3: Yes – some individuals have a competitive advantage. Slide put together by Dr. Jeremy Gibson (2021) https://i.imgflip.com/1inhwe.gif  Things that you can observe in nature Observation 1: More offspring are produced than survive Observation 2: Individuals vary (some is inherited) Observation 3: Some individuals have a competitive advantage in survival and reproduction Can we make any inferences from these observations? https://news.cgtn.com/news/ 78637a4e3463544f784d544e7a516a4e7a55444f31457a6333566d54/img/ 075c50ab1f9943cd95a905d2a2647951/075c50ab1f9943cd95a905d2a26479 51.png Slide put together by Dr. Jeremy Gibson (2021)  Things that you can observe in nature Observation 1: More offspring are produced than survive Observation 2: Individuals vary (some is inherited) Observation 3: Some individuals have a competitive advantage in survival and reproduction Can we make any inferences from these observations? Inference 1: Individuals that inherit traits that help them to survive and reproduce – leave more offspring. https://news.cgtn.com/news/ 78637a4e3463544f784d544e7a516a4e7a55444f31457a6333566d54/img/ 075c50ab1f9943cd95a905d2a2647951/075c50ab1f9943cd95a905d2a26479 51.png Slide put together by Dr. Jeremy Gibson (2021)  Things that you can observe in nature Observation 1: More offspring are produced than survive Observation 2: Individuals vary (some is inherited) Observation 3: Some individuals have a competitive advantage in survival and reproduction Can we make any inferences from these observations? Inference 1: Individuals that inherit traits that help them to survive and reproduce – leave more offspring. Inference 2: Favorable traits will accumulate in the population over https://news.cgtn.com/news/ time. 78637a4e3463544f784d544e7a516a4e7a55444f31457a6333566d54/img/ 075c50ab1f9943cd95a905d2a2647951/075c50ab1f9943cd95a905d2a26479 51.png Slide put together by Dr. Jeremy Gibson (2021)  Selection can act on behaviors Foraging behavior - Where to forage? - How long to stay in a patch? - How long to chase? Slide put together by Dr. Jeremy Gibson (2021)  Selection can act on behaviors Foraging behavior - Where to forage? - How long to stay in a patch? - How long to chase? Mating behavior - Who to mate with? - Risky behavior? - How long to display? Guppy(Poecilia reticulata) Slide put together by Dr. Jeremy Gibson (2021)  Selection can act on behaviors Foraging behavior - Where to forage? - How long to stay in a patch? - How long to chase? Mating behavior - Who to mate with? - Risky behavior? - How long to display? Guppy(Poecilia reticulata) Slide put together by Dr. Jeremy Gibson (2021) Variation in the Behavior of Guppies What did Dugatkin want to determine in the first set of experiments? Methods Collected 60 individuals from a river in Trinidad 1. Look at the tendency of the guppies to approach a predator Guppy(Poecilia reticulata) 2. Survival of guppies with behaviors Bold Timid Ordinary  Survival of guppies with different behavioral tendencies to inspect potential predators Figure 19.1 From Godin and Dugatkin 1996 Figure 1. © 1992, Oxford University Press  Survival of guppies with different behavioral tendencies to inspect potential predators Figure 19.1 From Godin and Dugatkin 1996 Figure 1. © 1992, Oxford University Press  Survival of guppies with different behavioral tendencies to inspect potential predators Bold guppies did not survive very long in the presence of a predator Figure 19.1 From Godin and Dugatkin 1996 Figure 1. © 1992, Oxford University Press  Survival of guppies with different behavioral tendencies to inspect potential predators Bold guppies did not survive very long in the presence of a predator Timid behavior is favored Predation acts as a selective agent over time Figure 19.1 From Godin and Dugatkin 1996 Figure 1. © 1992, Oxford University Press  Survival of guppies with different behavioral tendencies to inspect potential predators Why is boldness still present if it is selected against? Figure 19.1 From Godin and Dugatkin 1996 Figure 1. © 1992, Oxford University Press  Why is Boldness still present? Godin and Dugatkin wanted to determine why boldness was still present it is was selected against. Methods 1. # of times bright and drab approached the predator 2. Varied the presence of females Guppy(Poecilia reticulata) 3. Let females observe males in the presence/absence of a predator  Mean number of predator inspections by bright and drab male guppies Figure 19.2 From Godin and Dugatkin, 1996, Figure1. © (1996) National Academy of Sciences, U.S.A  Mean number of predator inspections by bright and drab male guppies Is there an effect of brightness on inspection? Figure 19.2 From Godin and Dugatkin, 1996, Figure1. © (1996) National Academy of Sciences, U.S.A  Effects of presence of female and male color on predator inspection behavior Predator inspections initiated by bright or drab males when females either present or absent. How does presence of female make a difference? Figure 19.3 From Godin and Dugatkin, 1996, Figures 2 & 3. © (1996) National Academy of Sciences, U.S.A  Effects of presence of female and male color on predator inspection behavior Predator inspections initiated by bright or drab males when females either present or absent. How does presence of female make a difference? Figure 19.3 From Godin and Dugatkin, 1996, Figures 2 & 3. © (1996) National Academy of Sciences, U.S.A  Effect of male color on predator inspection behavior 0 = drab 4 = bright What is relationship between boldness (inspections) and brightness of males? Figure 19.3 From Godin and Dugatkin, 1996, Figures 2 & 3. © (1996) National Academy of Sciences, U.S.A  Effect of male color on predator inspection behavior 0 = drab 4 = bright What is relationship between boldness (inspections) and brightness of males? Colorful males are generally bolder! Figure 19.3 From Godin and Dugatkin, 1996, Figures 2 & 3. © (1996) National Academy of Sciences, U.S.A  Effect of male color on predator inspection behavior 0 = drab 4 = bright What is relationship between boldness (inspections) and brightness of males? Colorful males are generally bolder! Figure 19.3 From Godin and Dugatkin, 1996, Figures 2 & 3. © (1996) National Academy of Sciences, U.S.A  Effect of male color on predator inspection behavior 0 = drab 4 = bright What is relationship between minimum distance of an approaching predator and brightness of males? Bright guppies are more likely to flee from predators before the predator gets to close! Figure 19.3 From Godin and Dugatkin, 1996, Figures 2 & 3. © (1996) National Academy of Sciences, U.S.A  Effect of male color on predator inspection behavior 0 = drab 4 = bright What is relationship between minimum distance of an approaching predator and brightness of males? Bright guppies are more likely to flee from predators before the predator gets to close! Figure 19.3 From Godin and Dugatkin, 1996, Figures 2 & 3. © (1996) National Academy of Sciences, U.S.A  Effects of presence of female and male color on predator inspection behavior A. Predator inspections initiated by bright or drab males when females either present or absent. B. Relationship between boldness and brightness of males. C. Relationship between minimum distance of an approaching predator and brightness of males. Figure 19.3 From Godin and Dugatkin, 1996, Figures 2 & 3. © (1996) National Academy of Sciences, U.S.A  How does boldness and male color affect female preferences in choice tests? Any predictions? Guppy(Poecilia reticulata) Slide put together by Dr. Jeremy Gibson (2021)  How does boldness and male color affect female preferences in choice tests? Any predictions? Selection can act on behaviors Mating behavior - Who to mate with? - Risky behavior? - How long to display? Guppy(Poecilia reticulata) Slide put together by Dr. Jeremy Gibson (2021)  Preferences of female guppies in choice tests bright male drab male Bright males were simulated to be bold Figure 19.4 From Godin and Dugatkin, 1996, Figure 4. © (1996) National Academy of Sciences, U.S.A  Preferences of female guppies in choice tests bright male drab male Drab males were simulated to be bold Figure 19.4 From Godin and Dugatkin, 1996, Figure 4. © (1996) National Academy of Sciences, U.S.A  Preferences of female guppies in choice tests bright male drab male Females preferred to mate with bold males when a predator was present Figure 19.4 From Godin and Dugatkin, 1996, Figure 4. © (1996) National Academy of Sciences, U.S.A  Preferences of female guppies in choice tests bright male drab male Figure 19.4 From Godin and Dugatkin, 1996, Figure 4. © (1996) National Academy of Sciences, U.S.A  Preferences of female guppies in choice tests bright male drab male Females assessed male boldness by examination of their color alone Figure 19.4 From Godin and Dugatkin, 1996, Figure 4. © (1996) National Academy of Sciences, U.S.A  Preferences of female guppies in choice bright male drab male tests Figure 19.4 From Godin and Dugatkin, 1996, Figure 4. © (1996) National Academy of Sciences, U.S.A BME 19.1: Do females really prefer bold males? When a predator was present, 14 / 20 female guppies preferred the bright male to the drab male when the bright male was the bold one 16 / 20 preferred the drab male to the bright male when the drab male was the bold one. bright male drab male From Godin and Dugatkin, 1996, Figure 4. © (1996) National Academy of Sciences, U.S.A Summary of guppy experiments Bold males selected against in first experiment. In presence of females, bright more likely than drab guppies to swim towards, and inspect, potential predators. Bright guppies more likely to flee before predator gets too close. Females preferred to mate w/ bold males when predator was nearby and bright males when predator absent; appearance = boldness? Bold males inspections may signal to predator that it has been spotted. Bold individuals more aware? Bold, healthy males may contribute more advantageous genes. Phenotypes remain in population when providing advantage to possessor; phenotypes selected against reduce ability of individual to survive or reproduce. Copyright © 2015 by AM Campbell, LJ Heyer, CJ Paradise. All rights reserved.