Introduction to Evolutionary Thinking 2025 PDF

Topic 2: Introduction to evolutionary thinking Sections 1.3, 1.4, 21.1 Topic 2: Learning Objectives After completing this lecture, you should be able to do the following (if you can’t, these are good questions to review during Office Hours). 1. Recognize the scienti...

Topic 2: Introduction to evolutionary thinking Sections 1.3, 1.4, 21.1 Topic 2: Learning Objectives After completing this lecture, you should be able to do the following (if you can’t, these are good questions to review during Office Hours). 1. Recognize the scientific method and how it applies to learning about evolution and ecology Relevance of experiments, observations, and comparative methods 2. Apply the “why” of the two Time scales of Causation and give examples 3. Know the definition of evolution (and spell it correctly) 4. Describe what can/cannot evolve and the timescales at which evolution occurs Thinking like a scientist What are the shared methods across different types of ecologists and evolutionary biologists? Central to any science is the “Scientific Method” The Scientific Method L1 1. Observations of natural phenomena. 2. Reason and creativity lead to the formation of a hypothesis. 3. Predictions based on the hypothesis are made. 4. Experiments are conducted to test predictions and determine if they support the hypothesis. 5. The data from the experiment are analyzed. 6. The hypothesis is supported or rejected based on the data. 7. Report and Repeat  How do ecologists and evolutionary biologists L1 apply the scientific method? Observational Studies Experimental Studies Comparative studies Dr. Biz Turnell Dr. Jared Ali Dr. Marjorie Weber Dr. Biz Turnell & Hawaiian crickets L1 Dr. Biz Turnell & Hawaiian crickets L1 Dr. Turnell found that in matings observed in the field (shown in blue) the number of microspermatophores received increased the percentage of offspring that hatched. Observational studies L1 Collect data on what happens in nature Document processes without interfering in them May be the only possible types of studies with some organisms Long‐lived, endangered or protected, challenging to handle Dr. Biz Turnell & Hawaiian crickets L1 Why did you become a biologist? I have always loved nature and am especially fascinated by animal behavior. When I found out you could watch animals behave for a living, I was sold! What is your favorite part about your job? I enjoy learning new things every day and getting to the bottom of tricky questions. That still fits my job description now that I work as a scientific editor instead of doing research myself. Dr. Jared Ali & plant chemistry L1 species interactions Dr. Jared Ali & plant chemistry L1 species interactions Using a combination of experimental treatments, Dr. Ali showed that nematodes were specifically attracted to infested plants, not simply the weevil larvae or plants that had been damaged. Experimental studies L1 Researchers can isolate the effects of specific variables Enables direct hypothesis testing May be challenging for logistical or ethical reasons; possible for a subset of organisms or study systems Dr. Jared Ali & plant chemistry L1 species interactions What advice do you have for aspiring biologists? Explore the world around you and find answers in the places few are venturing. Often these understudied areas are going unexplored because few people have the creativity and resourcefulness to make breakthroughs. Often those from disadvantaged backgrounds are well suited to handle such challenges, and the rewards are enormous! Dr. Marjorie Weber and plant diversification L1 Dr. Marjorie Weber and plant diversification L1 Comparative studies L1 Allow researchers to investigate hypotheses at a much broader scale Provide evidence for high‐ level patterns Generally do not provide direct evidence for how/why a pattern exists Dr. Marjorie Weber and plant diversification L1 What obstacles have you overcome to get where you are? MW: In school, I never thought I was the "smart kid" ‐ it was difficult to believe that I could become a scientist. However, with the help of inspiring role models, I slowly began to believe in myself. With perseverance, I was able to get a PhD and become a professional scientist. It is a wonderful job!  L1 Research across ecology and evolution takes many different forms But it all contributes to our understanding of how the natural world works We can apply the scientific method at L2 different scales: the many “whys” of life Why is this feather green? We can apply the scientific method at L2 different scales: the many “whys” of life Cause: genetics Floral scent profiles Cause: pollinator preferences Time scales of causation L2 Proximate causation – Immediate (short‐term) time scale – How actions take place Physiology Development Ecology Ultimate causation – Evolutionary (long‐term) time scale Phylogenetic constraints (prior variation) – Effects on Fitness of Ancestors Survival/Fecundity  Practice: proximate vs. ultimate L2 Ultimate: Proximate: Why does this raincoat exist?  Practice: proximate vs. ultimate L2 Ultimate: Proximate: Why do we see variation in flower color in snapdragons?  Practice: proximate vs. ultimate L2 Ultimate: Proximate: Why do many species of beetles have horns?  Time scale of causation L2 Proximate causation – Immediate (short‐term) time scale – How actions take place Physiology How does it happen? Development Ecology Ultimate causation – Evolutionary (long‐term) time scale Why does it – Effects on Fitness of Ancestors persist? Survival/Fecundity Connecting ecology and evolution to L2 time scales of causation Ecology: Evolution: Proximate: how Ultimate: how do organisms do organisms interact with the persist over environment in time the present moment What exactly is an evolutionary time scale? L4 What exactly is an evolutionary time scale? L4 Video: Evolution on a mega petri dish: https://www.youtube.com/watch?v=plVk4NVIUh8  Evolution in popular media How anything changes over time Evolution of the Windows Logo Star Evolution Pokémon Charmander Evolution What is evolution in a biological context? L3 Generation 1 Generation 2 Descent with modification: a change at the population level from one generation to the next  Caterpillars turn into moths L3 Not all change is Human babies gain teeth biological evolution Flamingos change color based on their diets Do individuals evolve? L4 Is this evolution? L4 Evolution occurs at the level of the population L4 Generation 1 Generation 2 OR How does evolution happen? Generation 1 T5: mechanisms of microevolution Generation 2 What do we need to learn about to understand how evolution works? T3 What enabled the origination of life? T4 What are the requirements for evolution? T5 What are the mechanisms of evolution? T6 Mechanism: natural selection Recap of Topic 2 The scientific method ⇒ proximate and ultimate causes for biological patterns and processes Evolution is: …descent with modification …change from one generation to the next Two questions Evolution is not: on HW 1A …a process that only occurs on ultra‐long time scales …all instances of change over time Topic 2: Learning Objectives After completing this lecture, you should be able to do the following (if you can’t, these are good questions to review during Office Hours). 1. Recognize the scientific method and how it applies to learning about evolution and ecology Relevance of experiments, observations, and comparative methods 2. Apply the “why” of the two time scales of causation and give examples Questions on HW 1A 3. Know the definition of evolution (and spell it correctly) 4. Describe what can/cannot evolve and the timescales at which evolution occurs Climate change is causing some plants to flower earlier Learn more about Dr. Tanisha Williams and her work at: https://projectbiodiversify.org/2020/08/18/ tanisha‐williams/