migration, altruism, communication

Question 1

reasons animals move:

Answer 1

• searching: goal directed
• homing: repetitive
• dispersal: leaving permanently
• migration

Question 2

what are reasons for dispersal:

Answer 2

• avoiding competition
• avoiding inbreeding
• colonizing new habitats

Question 3

what is migration?

Answer 3

• relative long distance travelling on a seasonal basis
• requires navigation

Question 4

ultimate reasons for migration?

Answer 4

• help animals survive and reproduce
• evolved since benefits outweigh costs

Question 5

what are the benefits of migration?

Answer 5

• allows access to food during seasonal changes that influences food availability in some areas.
• the day time duration changes with season and so does the foraging habits of animals.
• to find suitable temperatures for each species.
• limited locations for reproduction
• Facultative migration: some individuals from the population migrate.

Question 6

what are the costs for magration?

Answer 6

• extra body weight to withstand travelling
• dying during migration e.g., from predators, exhaustion.
• susceptibility to parasites–heavier investment to immune defence.

Question 7

what are the phylogenetic methods in tracing evolutionary origins of migration?

Answer 7

• comparing between species behavioural differences.
• matching behavioural data with genetic relatedness between species-phylogeny.

Question 8

what are the mechanistic reasons for migration?

Answer 8

• navigation (i.e., visual: position of the sun and the stars, landmarks.)
• magnetic (earth’s magnetic field e.g., spine lobsters, olfactory).

Question 9

what is developmental reason for migration? add an example:

Answer 9

• the ability of migration has developed during ontogeny.
• ungulate migration in Africa: Young individuals can learn aspects of migration from adults who migrated before

Question 10

what are the components of the signalling system?

Answer 10

• signal
• cue
• sensory modality

Question 11

what is a signal?

Answer 11

a feature or behaviour of the producer that influences the behaviour of the receiver and that evolved specifically for that reason.

Question 12

what is a cue?

Answer 12

any feature or behaviour that can be used to guide any action.

Question 13

what are the sensory modalities?

Answer 13

• vocal
• olfactory
• tactile
• electric
• visual

Question 14

what are the crucial conditions for a signal to evolve?

Answer 14

1. from the producer side: signal needs to be informative. indicate a specific feature.
2. receiver must be able to perceive and adjust its behaviour in accordance to the signal.

Question 15

how does a cue convert to a signal through evolution?

Answer 15

1. a cue that is useful for receiver is picked up by the receiver.
2. gradually, the receiver attends to it more.
3. the signaller is forced to elaborate the cue more.

Question 16

what are the intentions of signals?

Answer 16

predictive of future behaviours of the signaller by the receiver and allows for behaviour adjustment–benefits both parties.

Question 17

how is communication reliability ensure?

Answer 17

• interest of signallers and receivers overlap.
• indexes of quality (imposed by anatomical constraints)
• costly signalling (imposed by costs of signalling).

Question 18

what is the Handicap principle?

Answer 18

it is when a receiver attends to reliable signals. their reliability are ensured by the cost of signal, due to the costs signals are more likely to be displayed by highly motivated individuals, thus cheating is unlikely.

Question 19

what are examples of indexes of quality?

Answer 19

• body size: larger toads produce lower pitch calls than smaller ones.

Question 20

give an example of Handicap principle.

Answer 20

• begging calls demonstrated a positive - correlation with need for food.
  unreliable call have no correlation.
• begging is costly as it attract predators.
• energetically costly, birds that call longer have lower body mass (the cost).