Ecology BIO 340 What is Ecology The scientific study of the interactions that determine the distribution and abundance of organisms

Introduction What is not ecology?

Biological Disciplines Relating To Ecological Study PHYSIOLOGY BEHAVIOR GENETICS Applied Ecology; Management EVOLUTION 7

18th Century Thomas Malthus Exponential Growth

19th Century Natural History Human Demography

Ernst Haeckel Defined “ecology” Coined phrase “ontogeny recapitulates phylogeny” Studied Foraminiferans Controversial ideas

20th Century Lotka & Volterra (1920’s) Model population growth Gause (1920’s) Manipulative Experiments

20th Century Leopold (1930’s) Natural Resources MacArthur (1960’s) Mathematical Ecology Geographical Ecology

20th Century Lindeman (1942) Trophic Dynamics Hutchinson (1950’s) Niche Concept

? 20th & 21st Century Charles Krebs Populations/Cycles Monica Turner Landscape Ecology BIO 340 Student

Introduction Major Questions Where are organisms found? Where aren’t organisms found?

Introduction Major questions How many are found there?

Introduction Major questions Why are organisms found here and not there? alvar

Introduction Levels to ask questions Individuals Behavior Physiology

Introduction Levels to ask questions Populations Change in size Temporal & Spatial

Introduction Levels to ask questions Communities Biotic interactions

Introduction Levels to ask questions Ecosystems Community & Physical Environment

Introduction Levels to ask questions Landscapes Spatial patterns

Introduction Levels to ask questions Biosphere

Organization of Biological World Biosphere Landscape Ecosystem Community Population Individual Organ Tissue Cell Organelle Atom INCREASED KNOWLEDGE INCREASED COMPLEXITY

Types of Ecological Study AUTECOLOGY Study of individuals Physiology /Environment

Types of Ecological Study SYNECOLOGY Study of groups of organisms Community level and above

Introduction How to look at a question Proximate explanation

Introduction How to look at a question Ultimate explanation “Nothing in biology makes sense except in the light of evolution” Theodosius Dobzhansky

Introduction Major Advances Mathematical Models

Introduction Major Advances Evolution

Introduction Major Advances Hypothesis Testing Testing ideas about how the natural world works A hypothesis is developed to explain an observed phenomenon. Example: giraffes have long necks because the long necks enable them to reach food that is unavailable to others.

Testing Ideas about How the Natural World Works Null Hypothesis Hypothesis of no difference Example: The length of a giraffe’s neck does not influence the height at which it forages. Alternative Hypothesis Example: The length of a giraffe’s neck does influence the height at which it forages. Figure 1.9b Caption: (b)Although it is common to see photos of giraffes straining to reach leaves high in trees, these almost always depict dominant bull giraffes, which feed high in vegetation much more frequently than do other individuals. Dominant bulls are a small proportion of the total population

Percentage of feeding bites Most feeding is done below neck height. Males Females 7 7 6 6 5 5 4 4 Feeding height (meters) 3 3 Figure: 1.9a Caption: (a) These data plot the proportion of bites that male and female giraffes take at different heights. The drawings show the average size of a male and female. 2 2 1 1 20 40 20 40 Percentage of feeding bites

Testing Ideas about How the Natural World Works Null Hypothesis Hypothesis of no difference Example: The length of a giraffe’s neck does not influence the height at which it forages. ACCEPT Alternative Hypothesis Example: The length of a giraffe’s neck does influence the height at which it forages. REJECT Figure 1.9b Caption: (b)Although it is common to see photos of giraffes straining to reach leaves high in trees, these almost always depict dominant bull giraffes, which feed high in vegetation much more frequently than do other individuals. Dominant bulls are a small proportion of the total population

Testing Ideas about How the Natural World Works Null Hypothesis Hypothesis of no difference Example: The length of a giraffe’s neck does not influence the height at which it forages. ACCEPT So why do they have such long necks? Alternative hypotheses suggest a different explanation Example: giraffes have long necks because long necks are effective weapons for one male against another during mating (Simmons and Scheepers).

Hypothesis Testing and Experimentation Testing Ideas about How the Natural World Works The predictions made by each hypothesis are determined Observations are made and/or an experiment is designed to obtain data regarding the predictions