1. Animal Behaviour Part II
SBI3UP

2. Behavioural Traits can Evolve by Natural Selection….
This can occur…
Ex1. Between closely related species
Ex2. Within animal species

3. Ex 1:Between closely related species:
Drosophilia: different courtship songs
Voles: some species both males and females care for young, in others only maternal care

4. Ex 2:Within animal species:
There is variation in Prey Selection
Among animals
California coastal snakes vs inland snakes
CCS eat yellow slugs while inland snakes refuse them (feed on frogs)

5. Natural selection favours behaviours that increase survival and reproductive success through…
Foraging Behaviour
(incudes eating and mechanisms used to recognize, search & capture food)
Mating Behaviour
( aka. Sexual selection)

6. 1. Foraging Behaviour
Considers the compromise btw. Nutrition benefits vs. the cost of obtaining food
(aka.Optimal Foraging Theory)
Example: Bluegill sunfish preying on Daphnia; will select larger prey bc they supply most energy
*Note: Larger fish for more energy, but also select smaller if the larger prey are further away

7. 1.Foraging Behaviour cont’d
Risk of Predation is the most significant cost to a forager
Example: Mule deer are preyed upon by mountain lions
Therefore, they feed in open areas, avoiding both forest edge and interiors

8. Mating Behaviour
Includes seeking /attracting mates, choosing mates, & competing for mates
Let’s explore:
Mating systems and parental care
Sexual Selection and Mate Choice

9. 1.Mating systems and parental care
Types of Relationships:
Promiscuous= no strong pair-bonds/ relationships
Monogamous= one male mating with one female/ strong pair bonds
Polygamous= multiple mates

10. 1.Mating systems and parental care
PARENTAL INVESTMENT= time/resources expended for raising offspring
Ex: monogomy->more successful offspring if males help nurture partner
Vs.
Polygamy->males maximize reprodutive success by seeking multiple mates

11. Sexual Selection is a form of Natural Selection…
Intersexual Selection= choosing mates on the basis of specific characteristics (ie.mating songs, courtship dances)
Ex: Male competition for mates
Agonistic behaviour
Stronger males=
Better reproductive
abilities “ more fit”

12. Game Theory
strategies whereby the outcome depends on each individual’s strategy and the strategies of other individuals
E.g. Side-blotched lizard
3 Male phenotypes:
Orange throatmost aggressive &defend large territories
Blue throat  aggessive & defend smaller territories
Yellow throat  nonterritorial and mimic females
Therefore, the relative success of males varies with the abundance of other types.

13. Altruism A.k.a. selflessness Example.
Increasing the fitness of the population as a whole, even at the expense of their own
Example.
1 -Ground squirrels give a high-pitched alarm call alerting all indivuals
In this case there is greater risk to squirrel
2 - Bee societies: workers sting intruders to
Protect hive

14. Inclusive Fitness
Total effect an individual has on proliferating its genes by:
1)reproducing
2) Helping relatives raise offspring

15. Hamilton’s Rule
A quantitative measure for predicting when altruism will be favoured by natual selection
Altruistic acts depends on:
1.Benefit to the recipient[ B]
2.Cost to the altruist: [C]
3.Coefficient of relatedness:[ r]
probability that a particular gene present in one individual will also be present in the second individual
Note : Altruistic act is favoured if: rB > C

16. Kin selection
Inclusive fitness; individuals help relatives raise young

17. Reciprocal Altruism No kinship; behave altruistically
Occurs in species with stable social groups
“Tit for tat strategy”
Examples:
Wolves: food offerings

18. Social Learning Learning through observing others
Forms the roots of culture
Mate choice copying= individuals copy the mate choice of others
Example: female guppies who generally prefer orange males will select non- orange males b/c they see other females engaging courtship with non-orange males

19. Evolution and Human Culture: Things to consider…
Why do you think that certain behavior characteristics in humans exist?
Are they expression of genes perpetuated by natural selection?
Or non-genetic, environmental factors?
What defines acceptable behavior in humans?
What examples of unacceptable behaviour might enhance an individual’s Darwinian fitness?