General Ecology: Lecture 1 September 29, 2003 I. II. Course Logistics (see handouts) A. NOTE: Before lab this week, download and read Protist Ecology Lab: from Intro through Part A, skim the rest. Mimicry Lab: Read Intro through Step 5, p. 5, skim the rest. What is Ecology? A. Defined: “Ecology is the scientific study of the interactions that determine the distribution and abundance of organisms.” 1. Spatial distribution/abundance [Distribution map] 2. Changes of these distributions/abundances over time (daily, weekly, seasonally, yearly, interannually…) [Figure showing monarch migration; also one with differences in ice] a) Several fields of study are essential to our understanding of ecology 1. Examples given for Physiology, Animal Behavior, Genetics, Evolution, Microbiology 2. Focus on monarch butterflies, but you should be able to come up with your own examples. B. Basic Problems and Approaches in Ecology 1. Descriptive: Natural history of organisms a) Examples of natural history questions 2. Functional: Cause-effect relationships currently in operation; “proximate” causes of current distribution/abundance parameters. a) Examples of “functional” questions 3. Evolutionary: a) Examples of evolutionary questions. C. Levels of integration in biology 1. Bottom line: We know much less about ecology than about how organisms work at a cellular/molecular or individual level. D. Application of the Scientific Method 1. As in all scientific fields, the basic methodology is the scientific method a) Example: Go through steps of the scientific method to explore why different species of birds have different clutch sizes of eggs. (NOTE: See Lack’s hypothesis in Ch. 2.) 1. What type of question is this? (Natural history? Functional? Evolutionary?) 2. Testing ideas a) Lab. b) Field c) Mathematical modeling 3. Some difficulties in studying ecology: a) Multiple/interactive causes of ecological phenomena and/or difficulty in testing single variables. 1. Example… b) Difficulty in manipulating some systems mean that even finding correlations can be a challenge, let alone determining cause-effect 1. Example III. Ecology and Evolution A. Basic assumption in ecology: The patterns of distribution and abundance that we see today, as well as the specific characteristics of populations (lifespan, reproductive output, territorial behavior and territory size, etc…), have been shaped by the processes of evolution acting on those populations. B. Quick review of evolutionary principles 1. Process of natural selection as a key mechanism (but not the only mechanism) of evolution a) Review: Basics of natural selection 2. Types of selection 3. How to test evolutionary questions? a) Lack’s hypothesis (discussed earlier in example of the scientific method) 1. Tests on many species of birds support his hypothesis, while some do not. 4. Concept of coevolution a) One type of selective pressure is the effects of one species on another, and visa versa. 1. Mutualistic coevolution Example 2. Antagonistic coevolution Examples b) NOTE: Concept of coevolution is best applied to pairs of species. 1. When groups of species are involved, it is considered “diffuse coevolution”. Study questions (not turned in, but to use as a study aid) ** Don’t forget to do Question Set 1, given on a separate handout. To be turned in Friday! 1. Name some other areas of biology relevant to ecology, and come up with a question that you might explore in each of those fields that is relevant to ecology. 2. Provide examples of descriptive, functional and evolutionary questions related to the study of ecology that you might ask about a. Egg production in birds b. A topic in ecology of your own choosing. 3. Be sure you can define and provide examples of independent and dependent variables in hypotheses, experiments and field studies. For example, state what the independent and dependent variables are in the hypotheses below. 4. Answer Question 1.7 (p. 16). Be creative and think about what you have learned in other courses! 5. Describe the process of natural selection in your own words. 6. Explain directional, disruptive and stabilizing selection, and provide an example of each. 7. What is coevolution? 8. What is Lack’s hypothesis? How did Lack (and others) test this hypothesis? Is the hypothesis primarily descriptive, functional or evolutionary?