4. Natural Selection equally operates on behavioral traits, no matter how trivial The male mole cricket The wing structure, singing and burrow-digging behavior are all precisely co-adapted to produce an efficient sound aimed at female.
6. The Black-headed Gull removing the empty eggshells, less vulnerable to crows and herring gulls.
7. Kittiwake gull do not have to throw away the Egg shells, with nest on the cliff ledges
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9. It often result not in the best but in the best compromise, because
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11. not the best but the BEST COMPROMISE displays or loud songs attract their mates, are also likely to attract the a predator. the croaking frog attracting mate….. frog-eating-bat.
12. Evolutionarily Stable Strategies(ESS),simply a specific action of an animal, as removing egg shell. female wasps which uses burrows dug by other wasps; the success of the strategy depends on whether few or many digger wasps present. frequency dependent.
13. ESS benefits depends on what other animals around are doing, Applied to aggression , the best strategy (e.g attack or retreat) is very dependent on what strategy an opponent takes up.
14. Cultural Transmission of Behavior a behavioral trait may be horizontally propagated, without any genetic changes involved ______ the cultural evolution. E.g : the human languages and culture In other primates, Macaques washing potatoes. Chimpanzees fish for termites Opening of milk bottles by blue tits in UK
15. Maintenance of the song dialect in many birds e.g White Crowned Sparrow. The chick’s ability to learn song depends on both biological and social cues.
16. The chick’s ability to learn song depends on both biological and social cues. A.If exposed to the songs of many species while growing up, the chick invariably picks out and learns the correct song. B.If isolated during the song-learning phase, the chick produces only a rough outline of the normal song.
17. C.If deafened at an early age, the chick’s song is entirely abnormal. D.A chick that is socially (but not acoustically) isolated from its own species but in contact with the adult of another species learns its tutor’s song.
18. Alaram Calls development , in black bird Chicks see the plastic bucket while the adults are shown the stuffed owl
19. Genes and Behavior Genes are the products of evolution. Evolution is about changes in gene frequency “the genes making the more fit” Easy to contemplate genes for physical characters, but GENES FOR BEHAVIORAL TRAITS! Behavior: Interaction of nerves, muscles, sense organs, hormones etc. Many difficulties in studying behavioral genetics(especially in humans)
20. Drosophila Bar eye, reduces the number of facets in compound eye. The white eye, reduces pigment O-> difficulty in locating O+ Vestigial or dumpy Wings, O-> unable to vibrate wings All these genes affect the courtship behavior
21. Drosophila Mosaic Flies(Hotta 1976) are genetically different in different parts of their body. E.g. Gynandromorphs: some cells are O-> some O+.
24. We could not expect such results in vertebrates, where sexual behavior develops as a result of hormones, secreted by the gonads, that affect the whole body
25. We could not expect such results in vertebrates, where sexual behavior develops as a result of hormones, secreted by the gonads, that affect the whole body
26. We could not expect such results in vertebrates, where sexual behavior develops as a result of hormones, secreted by the gonads, that affect the whole body
27. An examples of naturally occurring behavior showing a classical Mendelian pattern Gwadz's (1970) . The females of different populations of mosquitoes become sexually receptive at different times after emergence. The females of one strain GP receptive 38h. In another strain TEX takes much longer 120. Hybrids between the two strains TEX/GP) , with a mean of about 54 h, but with a slope like GP strain. When the F1 hybrids were backcrossed to the GP and TEX parental strains, the results were compatible with the idea that early receptivity was due to a single, autosomal, semidominant gene.
28. GP[38 h] X TEX [120 h] GGTT F1 GT[56 h] GT X GG
29. Classic Mendelion Results are rare in Behavior Genetics. Behavioral traits affected by more than one gene, or large number of genes may interact to produce a certain behavior, which in most of the cases is not an all or non phenomenon. Mice can not be classified as aggressive and non-aggressive____________Continous Variation need quantitative genetics.
30. Migratory Restlessness in Different populations of Black Cap Finland Corelation between how far they have to migrate and the intenisty of migratory restlessness at the time of migration Those who had to go far-away___More restless Crosses between birds from different populations resulted in hybrids with intermediate degrees of restlessness Canary Islands AFRICA
31. Two lovebirds of the Genus Agapornis The peach-faced tuck the nest material in to their rump, while Fischer’s lovebird carry the strips singly in their bill When crossed The hybrid for some time not capable of building the nest because they were attempting some sort of compromise between the two.
32. After months of practice, successful only in 41 % trials Two years later 100 % sucessful, but before carrying a strip in their bill they would make a brief turning movement of the head( a reminiscent of tucking). Hybridswere sterile so the F2 or F3 could not be known.
33. Genetic Lines relevant to Behavior can be selected The Rate of Mating in Pairs of Drosophila
39. bees colony, worker bees are responsible for collecting food, defending the colony,and caring for the nest and the young, but they are sterile and create no offspring.
40. Scientists now recognize that among social insects, such as bees, wasps, and ants, the sterile workers are actually more closely related genetically to one another and to their fertile sisters, the queens, than brothers and sisters are among other organisms.
41. Samuel Butler, A chicken is an egg’s way of producing another egg’ An animal is a gene way of producing more copies of that gene Some people uneasy with A gene-centered view of evolution / existence. Consider Parental Care
42. Success in evolutionary terms means leaving offspring that themselves reproduce, but the 'success' of an individual is short-lived and ephemeral. In sexually reproducing species, an individual does not survive for more than one generation. But the genes are passed on to the future generations>>>>
43. Genetic variation in ('genes for') a tendency to defend young—perhaps mediated through variations in the level of a hormone —will result in a variation in the numbers of offspring that survive to pass on the favoured genes, and so on down the generations.
44. The direct line of parents to offspring is the only way that genes are passed on into the future, but direct parental care is not necessarily the only genetic strategy that will be successful. Helping a brother, sister, or other relatives to reproduce may also enable genes to perpetuate themselves.
45. Inclusive fitness Hamilton invented the idea of inclusive fitness. Fitness can be divided into two components: Direct fitness results from personal reproduction Indirect fitness results from additional reproduction by relatives, that is made possible by an individual’s actions.
46. Hamilton’s Rule The rule generalized the circumstances in which relative-helping of various sorts would evolve into the equation: Br - c > 0, Bis the benefit to the relative/actor and r is the coefficient of relatedness c the cost to the relative-helping genotype.
47. r b - c > 0, calculating values for r, b and c. rdoes not cause problem. r is the probability that the homologous alleles in two individuals are identical by descent. From basic genetics Full Siblings, and Parents & Offspring have a 50 per cent chance of sharing a given rare gene (r = 0.5); Nieces and Nephews have a 25 per cent chance of sharing with an uncle or an aunt (r = 0.25) and so on.
48. Calculating r To calculate r one should trace each path between the two individuals and count the number of steps needed. Then for this path r = 0.5 (number of steps) Thus, if two steps r for this path = 0.5 (2) = 0.25. To calculate final value of r one adds together the r values calculated from each path.
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52. It is not just the degree of relatedness that matters, but the number of relatives that can be helped. Haldane, “ I am prepared to lay down my life on behalf of four grandchildren or eighth first cousins!”
53. r b - c > 0, values b and c More Problematic How to measure the effect of help. If we observe one animal helping another torear its yourn, how do we know that the parent wouldn’t have been just as scessful without the help? Ando how do we know whtat the cost to the helper was in terms of the offspring it wold have had if it hadn’t been helping someone else? The mythical offspring
54. r b - c > 0, values b and c, Some Practical Examples Hamilton on Isoptera(termites) and Hymenoptera(ants, bees, wasps) With Extreme Altruistic Behavior.
57. How to Explain the sociality of Termites 1 0 0 0, 0 0 0 s Offspring
58. Naked Mole-rats Naked mole-rats are highly unusual mammals. They are nearly hairless and ectothermic. They are eusocial and, like termites, can digest cellulose with the help of bacteria in their gut.
60. Naked Mole-rats The behavior of naked mole-rats is similar to that of colonial insects. There is a single reproductive female (queen) and 1-3 reproductive males. The remaining individuals act as workers. They dig tunnels to find food, defend the tunnel system from other mole-rats, and tend the young.
61. Naked Mole-rats Leading hypothesis for why naked mole-rats are eusocial is inbreeding. Average coefficient of relatedness is 0.81 and about 85% of matings are between parents and offspring or between full siblings.
62. Naked Mole-rats Despite high level of relatedness conflicts still occur because reproductive interests of workers and reproductives are not identical.
63. Naked Mole-rats Queens maintain control through physical dominance. Queen aggressively shoves workers who do not work hard enough and shoves are mainly directly towards less closely related individuals. Workers double their work rate after being shoved.
64. Naked Mole-rats In addition to inbreeding, ecological factors such as severely limited breeding opportunities and group defense appear to contribute to eusociality in naked mole-rats.
65. “We are survival machines—robot vehicles blindly programmed to preserve the selfish molecules known as genes”
66. You can study other examples in the Chapter 5 reading given to youOther examples are from Birds, Jackals etc
