Lecture 1 + 2 Flashcards
Ecological phenomena can occur at a range of
- biological scales
- spatial scales
- temporal scales
- all of the above
All of the above
Generally, most studies will evaluate a hypothesis based on whether the p-value is
p < 0.05
___ are functioning groups of individual organisms of the same species in a defined location
Populations
The principal sources and approaches used to gather ecological evidence include ___
Observations, experiments, and mathematical models
Sluggish oceans’ circulation cause in part by melting of Greenland and Arctic Ocean ice. Consequences?
Faster build-up of CO2 in the atmosphere
Greater weather extremes (cold, heat, floods, droughts)
May become far worse
Ice Loss and Polar Vortex
The loss of sea ice may be worsening the polar vortex, allowing cold blasts the dip south from the Arctic
Ecology is a science
Hypothesis generation and testing
Testing through models, observations, and experiments
Science is a process for gaining new knowledge, for improving understanding. NOT a list of facts or theories.
Ecology is not Environmentalism
Ecology: scientific study of the interactions of organisms and their environment; a field of biological science
Environmentalism: concern for and action toward protecting the environment; a social movement
Ecological science can feed into environmentalism
Scientists have an ethical responsibility to share their knowledge with the public (shale gas, methane, and global warming)
Hierarchical scales of organization in ecology
- biosphere
- ecosystem
- community
- population
- organism
- organs and tissues
- cells
- organelles
- molecules
Population
Groups of organisms of the same species in a defined area
Communities
All of the populations (different species) in a defined area
Ecosystems
Community of organisms AND the physical environment in a defined area
Biosphere
All life interacting with the physical environment at the scale of the entire planet
Properties observed at a particular level of organization arise out of the functioning of the parts at lower levels
cells -> organs
communities -> ecosystems
Important to look at lower levels, but we can often predict and understand behaviour at one level of organization without fully understanding the functioning at lower levels
ex. Boyle’s Law (1662) for gases:
pressure * volume = constant
understanding of this based on quantum mechanics at the level of individual gas molecules not developed until 250+ years later
similarly, we can predict the consequences of adding nutrients to a lake (ecosystem) without fully understanding the functioning of algal populations
Does the nitrogen added to an ecosystem from the atmosphere (in acid rain) affect biodiversity? How might scientists (ecologists) test the hypothesis that yes, adding more nitrogen changes diversity?
Observations: compare biodiversity across ecosystems that are similar except in terms of how much nitrogen inputs they get from the atmosphere
Experiments: add nitrogen and see how the ecosystem responds
Experiment: adding nitrogen to grassland plots at different levels
Much less “noise” or variation in the pattern, compared to observational data.
But hard to know if the effect is consistent across sites with different climate, soil types, etc.
Ecologists have the greatest confidence in understanding relationships when ___
observational data agree with experimental data
Experimental Lakes Area
An experiment, but with no replication. Instead, comparison to a reference lake that received no acid.
Effects of acid observed at far higher pH’s (less acid) than had been predicted from lab studies of populations of fish.
Lake trout in a reference lake receiving no acid are healthy.
Lake trout in the acidified lake are clearly underweight in the years before they are finally gone.
When evaluating case studies in ecology, it is important to keep in mind:
- phenomenon occur at a variety of scales
- data and evidence can come from a variety of sources
- scientific evidence is necessary
- all of the above
- none of the above
All of the above
Which field of ecology studies trends and fluctuations in the number of individuals of a particular species at a particular time and place as a result of birth and death rates?
- Community ecology
- Systems ecology
- Ecosystem ecology
- Population ecology
Population ecology
A researcher is studying how the physiology of individual single-celled organisms of the same species. This is an example of studying ecology at what level?
- organismal
- population
- ecosystem
- community
Organismal
Which approaches can ecologists use to answer research questions?
- mathematical models
- controlled laboratory experiments
- manipulative field experiments
- observational data
Say you go and measure the diameter of trees in old growth forests throughout 30 plots of land in Argentina. You want to know if tree size differs between sites. This is an example of what type of study?
Comparative field observation study
You design an experiment to test how ultraviolet radiation impacts the development of a species of frog tadpoles. You set up your experiment so that there are 50 replicates, instead of only 10. Why is it a good idea to have so many replicates?
The more replicates you have the greater the likelihood of obtaining accurate results
You compile a model to test how dissolved carbon dioxide levels are affecting calcium deposition in the Pacific Ocean as a result of climate change. Your model indicates that many species relying on carbonate for shell deposition will not be able to survive due to the projected future changes in dissolved carbon dioxide levels as a result of climate change. What is the likely conclusion to draw from this result?
Your model is only a prediction and can be applied cautiously to help land managers and other researchers
