Ecology BIOB50 Lecture Notes PDF

# Lec 1 → CH 1 ## What is Ecology? - Ernest Haeckel - Named the term Oekologie mid 1800s ## Ecology - Study of interactions of organisms with the environment that determines their distributions + abundances - Studies: ## Everything in nature is interconnected ## Ecology in the Anthropocene -...

# Lec 1 → CH 1 ## What is Ecology? - Ernest Haeckel - Named the term Oekologie mid 1800s ## Ecology - Study of interactions of organisms with the environment that determines their distributions + abundances - Studies: ## Everything in nature is interconnected ## Ecology in the Anthropocene - The great acceleration - Humans' impact over the past 50 years has changed the course of Earth in many ways some irreversible ## Ecologies have to look at new challenges including - Climate change, land use change, extinction, invasive species, ecosystem homogenization, overexploitation. - The world is changing and these changes will impact both personal and professional aspects ## Levels of organization - Individuals - Populations - same individuals in a specific area - Community - different species interacting in the same area - Ecosystem - community physical environment - Biosphere - all ecosystems ## How do we learn about it 1. Observation + natural history 2. Experimental ecology and Null hypothesis testing 3. Multiple hypothesis testing with best-fit comparisons 4. Ecological modelling ### Observation + natural history - Study of animals, plants, and fungi - Focusing on observation and description - Historical foundation of ecology differing from modern approaches where observations are typically combined with other approaches of scientific analysis - Modern day approaches include focusing on broad ecological patterns combined with other approaches ### Experimental ecology and Null hypothesis testing - Second half of 20th century ecologists began to apply manipulative experiments and statistical hypothesis testing. - Based on observation (either direct or through knowledge from previous work / the literature), propose a question. - Based on your question, propose a null hypothesis (focal factor does not have an effect) and an alternative hypothesis (focal factor has an effect) - Design an experiment that alters/manipulates one or more focal factors (including controls with no manipulation for comparison) and can falsify the null hypothesis (e.g., show that the focal factor(s) do have an effect). - Analyze the data to arrive at results, and then an interpretation for the observations. - Interpretation leads to new questions and the process restarts. - The process is iterative and self-correcting. ### Multiple hypothesis testing with best-fit comparisons - Very difficult to repeat ecological experiments (due to changes in ecosystem over time), conducted logistically (biased towards small species and short timescales), or ethically challenged. - Instead, they use this. - Instead of falsifying a hypothesis for a specific factor having no effect the approach evaluates multiple competing hypotheses for their relative support by data. ### Ecological modelling - Models play a fundamental role in ecology. - Similar to experiments they allow exploring how various factors affect ecological dynamics but without experimental manipulation. - Models can be used in many ways → - understanding the mechanisms that lead to ecological patterns - testing complex hypotheses against data - estimating missing information (e.g., population numbers) - identifying what we don't understand about a system - providing forecasts - How much realism is included in a model depends on its purpose. - Many types are used such as conceptual, mathematical (may be analytical or stimulation-based).