Lecture 1 + 2 Flashcards
(21 cards)
What is a rank-abundance curve?
- One way to plot species abundance data
(an approach originated by R. H. Whittaker) - in which each species is represented by a vertical bar proportional to its abundance
(IMG)
Describe the community of which this plot is made of (IMG)
- Notice the long ‘‘tail’’ of rarer species
- A community with such striking disparities in abundance among species is said to have low evenness (low uniformity).
- A rank-abundance plot for a hypothetical community with perfect evenness would be flat instead of declining, indicating that every species had the same abundance
What are 3 examples of criteria used to quantify biodiversity?
- Species richness
- Diversity index
- Functional diversity
What is the diversity index?
Mathematical expression that combines species richness and evenness (how equal the community is numerically) as a measure of diversity
What is functional diversity?
- Variety and number of species that fulfill different functional roles in a community or ecosystem
- Functional diversity, influences ecosystem stability, productivity, nutrient cycling
What is deimatic display?
- Its used to intimidate predators and dissuade them from attacking
- Typically involves the display of some conspicuous color or structure
(IMG)
What are the different levels of explanations?
- Ultimate explanations –> evolution
- Proximate explanations –> mechanism
Name examples of evolutionary and
Evolutionary explanations:
- Evolutionary history (Did this behavior evolve in an ancestral species?)
- Adaptation (How does this behaviour maximize survival and/ or number of offspring)
Name examples of proximate expanations
Proximate explanations:
- Development (ontogeny (How did the animal develop this behaviour?)
- Causation (mechanism (What is the immediate cause for the animal to show this behaviour?)
What are these 4 types of explanations also known as?
Tinbergen’s 4 ways (IMG)
3 types of behavioural studies
- Field observations
- Field experiments
- Lab experiments
Name adavantages and disadvantages of field observations
Adv:
- Animals in real ecological context
Disadv:
- difficult to control variables
Name adavantages and disadvantages of field experiments
Adv:
- Can vary ecological context, stimulus conditions, etc. while maintaining animals in their natural environment
Disadv:
- Difficult to control external variables
- Manipulations may have confounding effects
Name adavantages and disadvantages of lab experiments
Adv:
- Able to vary treatments precisely while controlling for most extraneous variables
Disadv:
- Manipulations may have confounding effects
- Impoverished (poor) ecological context
- May get artifactual responses
What are the 7 deadly sins in the study of behaviour?
- Unjustified conclusions are made from observational (i.e., correlational) data.
- Data are not independent - pseudoreplication.
- Treatments are confounded by time and sequence effects.
- No efforts are made to avoid observer bias.
- Potential artifacts arise when animals are not accustomed to experimental
procedures. - Unsuitable controls are used.
- An attempt is made to “prove” the null hypothesis with small samples
How to avoid making these mistakes?
(Unjustified conclusions)
Correlation and causation
How to avoid making these mistakes?
(Data not independent)
Be aware of:
- Pseudoreplication: Use of inappropraite sample size OR treatments are not replicated and/or replicates are not statistically independent
- Litter effects: litter mates not statistically independent (shared ancestry and rearing environment)
How to avoid making these mistakes?
(confounded treatments)
Be aware of:
- Order effects: Data collected later in the study is systematically different from data collected earlier
- Temporal effects: Time of day/ year or cyclic changes.
- Repeatability: Panta rei (everything flows).
You can never really measure the same behavior on an animal twice because of learning and habituation - Winner/ loser effects: Winning a fight increases probability of subsequent wins with the same or other individuals
How to avoid making these mistakes?
How to avoid making these mistakes?
(observer bias)
- Clever Hans effect: unconsciously biasing behavior of animals
How to avoid making these mistakes?
(Potential artifacts and unsuitable controls)
- Ceiling effects: Subjects show a maximal response to all treatments. (Why we need negative controls)
- Floor effects: Subjects show a minimal response to all treatments (Need positive controls)
