Asking questions and testing hypotheses in animal behaviour

Question 1

Natural selection. Definition.

Answer 1

It’s the name for consistent difference in offspring production by different classes of reproducing entities, either phenotipically different organisms or genes. This leads to adaptation.

Question 2

Adaptation

Answer 2

Adaptation is the evolutionary process whereby an organism becomes better able to live in its habitat or habitats. Increases fitness.

Question 3

Evolution

Answer 3

is the change in frequency of heritable variants from generation to generation.

Question 4

Tinbergen’s four questions about behaviour. (4)

Answer 4

• Adaptive function. Current function / utility in nature - Evolution. Evolutionary history - Immediate causation. What triggers the behaviour? physiological processes - Ontogeny. How does it develop? genetic, experience & developmental processes

Question 5

Say if it is proximate or ultimate.

Answer 5

ultimate ultimate proximate proximate ultimate proximate or ultimate proximate ultimate

Question 6

How do ants build the bivouac? prox/ult?

Answer 6

Ants link together using their feet. Proximate

Question 7

What is the adaptive function of building bivouacs? prox/ult?

Answer 7

Bivouacs stabilise temperature and humidity. Ultimate

Question 8

Why build bivouacs instead of permanent nests?

Answer 8

Army ants have many larvae to feed. Temporary nests allow them to move regularly with the larvae to find new food sources. Ultimate

Question 9

Black headed gulls (Schwarzkopfmöwe) leave the nest undefended to take eggshells away. What is the function/ adaptive value of this behavious?

Answer 9

Eggshell removal reduces predation.

Question 10

Optimality

Answer 10

Optimality is defined as the point where the difference between benefits and costs for a behavior is maximized, which can be done by graphing the benefits and costs on the y-axis and a measure of the behavior on the x-axis.

Question 11

Optimality and natural selection

Answer 11

Natural selection leads to adaptations that maximise fitness benefits in relation to fitness costs.

Question 12

Parental survival is affected by clutch size(amount of eggs laid). Yes/No?

Answer 12

Yes.

Question 13

Enlarged clutch size decreases parental survival. Yes/No?

Answer 13

Yes.

Question 14

What is the Comparative approach?

Answer 14

Phylogenetic comparative methods (PCMs) use information on the historical relationships of lineages (phylogenies) to test evolutionary hypotheses.

Question 15

Asking proper questions. (4)

Answer 15

• Question - Hypothesis - Null hypothesis - Prediction

Question 16

Null hypothesis. When do we accept/reject it?

Answer 16

We reject the null hypothesis if the probability of obtaining the results in the sample when the null hypothesis is true is less than 5%.

Question 17

Null hypothesis testing

Answer 17

• Assume for the moment that the null hypothesis is true, and there is no relationship between the variables in the population. - Determine how likely the sample relationship

Question 18

Null hypothesis testing (3)

Answer 18

• Assume for the moment that the null hypothesis is true, and there is no relationship between the variables in the population. - Determine how likely the sample relationship would be if the null hypothesis were true. Need statistics! - If the sample relationship would be extremely unlikely, then reject the null hypothesis. If it would not be extremely unlikely, then retain the null hypothesis.

Question 19

Drawbacks of the null hypothesis. (2)

Answer 19

-5% false positives is a lot! (rejecting the null hypothesis when it is true) - the larger the sample the likelier it is to find a difference from zero

Question 20

What kind of evidence do we use for hypothesis testing? (3)

Answer 20

• Correlations - Experiments - Models

Question 21

Correlations is the same as Causation. Yes/No

Answer 21

NO! Correlation is not the same as Causation! Be careful!

Question 22

Experiments to test causality. Explain

Answer 22

Test the effect of X on Y. Manipulate only one variable (X), keeping everything else as equal as possible. - need appropriate treatment groups and controls - Random allocation by experimenter to treatment or control group - Avoid experimenter prejudice/bias