Lecture 3 - The Function & Evolution of Animal Behaviour Flashcards
What does it mean to have a function?
To have a function implies some sort of “design’ and this implies that a “designer” is involved.
What is the definition of selection?
Acts to sift variants of behaviour, favouring those that provide their bearer with greater representation in the next generation.
What is selection for survival?
Natural selection
Why is there a need for selection?
Environment is not static but dynamic and changes so animals must evolve to keep up with these changes
How does natural selection work in practice?
- Huge numbers of individuals are produced.
- Insufficient resources for all, so many die before reproducing.
- Individuals vary in attributes.
- Individuals with attributes better suited to environment are less likely to die.
- These individuals will be over represented in next generation.
What are phenotypes?
An expression of your genotypes. It is what you can see.
What is sexual dimorphism?
different behaviours by sexes to mate. overall population advantage .e.g male spotted by predators as visible but gets lots of mates
Behaviours are a result off…
A trade off between selective forces
How to stick insects find partners?
Not true hermaphrodites - one stick insect just needs to find another to reproduce
Behaviours function to maximise…
- Likelihood of long-term survival
- Lifetime reproductive output
What behaviours maximise survival?
- Hiding from predators
- Escaping from predators
- Increasing amounts of food eaten
- Reducing energetic costs
What behaviours aid reproduction?
- Increasing attractiveness
- Increasing access to mates
- Increasing fecundity
- Increasing survival of young
Example of how ostriches aid reproduction
Female is brown and male is black. They split the devision of labour equally. Females sit on eggs during day time and males at night time due to their colour
Example of prairie dog’s dysfunctional behaviour
Stand on their back legs and yell loudly to warn everyone that there is a predator and they need to go underground to a burrow. The caller will stand there until the predator is really close and everyone has gone underground
Example of common buzzards dysfunctional behaviour
mobbing - a group of prey species gather together to drive off predator. By clubbing together they are more successful and driving them out of their territory
Who does dysfunctional behaviours directly benefit?
individual
Who does dysfunctional behaviours indirectly benefit?
Kin and offspring
How have behaviours evolved?
Have more offspring and/ or enable species to continue for as long as possible
What is behaviour a compromise of?
Animal and the situation (despite the strength of selection pressures)
How to behaviours develop?
Refine previous behaviours exhibited by the species or its relatives
Do behaviours make an individual less fit that it previously was?
No
Why is the understanding of early relatives’ behaviours important?
We can better understand the behaviours we see today
What is epistasis?
a phenomenon whereby the expression of one gene depends upon the presence of the others around it. A gene can be expressed or repressed by the other genes around it
What is divergent evolution?
Evolution of different features from a common ancestor; resulting in differences between species.
