key points:#1) Many behaviors are affected by genetic differences. An example in Fruit Flies: Maggots that tend to "sit" next to the same piece of food, as contrasted with other maggots that rove.
The dominant form of the gene promotes "roving", #2) A human example of behavior affected by genetic differences: Alcoholism
The old question of "nature or nurture";
Studies of adopted children (adopted by non-relatives) Would this be independent of alcohol abuse in the adoptive family?
THE ANSWER: apparently there are two distinct genetic influences on alcoholism!
II) Adult-onset alcoholism Notice that genes can be part of the cause for a difference, without being the only cause. Sometimes people mistakenly think that genetic cause means a one-to-one relation between genes and effects A given behavior might be influenced by many genes, and also influenced by environmental differences. Many examples in nature include inheritance of frog calls, bird calls, mating dances, etc. etc.
#3) Animal behavior is sometimes altruistic Is this contrary to Darwinian evolution!? Can we predict under what circumstances natural selection will favor genes that increase self-sacrificing & risky altruistic behavior?
In the case of parents protecting their offspring, such behavior doesn't surprise us: because the kids have the same genes as the parents, therefore risky behavior by the parents will improve the chances of those genes being passed on to future generations. Most people have no trouble believing in "Maternal Instincts" or that it is caused by genes evolved by natural selection. These genes slightly reduce the "fitness" of the mother animal, but nevertheless are favored in evolution if they cause enough increased survival in related animals that carry many of the same genes. This is the concept of "inclusive fitness". A non-behavioral example of inclusive fitness sometimes occurs in the evolution of bad flavors in animals; that teach predators not to eat that species any more. #4) Notice that each parent has ~ 50% the same genes as offspring; Then also notice that brothers & sisters also have ~ 50% the same genes. Therefore why shouldn't evolution favor genes that cause offspring to risk their lives to help each other?
Prairie dogs have alarm calls, that warn each other of predators. Hamilton's law predicts that genes for altruistic behaviors should tend to increase in % when their "cost" (reduced survival of an animal doing the altruistic act) is less than the benefit to other animals multiplied by their coefficient of relatedness .
B * r > C #5) Animal societies (including herd behavior, etc.) result from complex sets of genetically-determined altruistic behaviors.
The most extreme examples of altruistic behaviors occur in the social insects. Bees, wasps, ants and termites (although notice that many species of bees are NOT social)
#6) It was already known that sex determination in Hymenoptera works by fertilized eggs becoming (diploid) females, and unfertilized eggs becoming (haploid) males! In contrast to most animals, in which siblings have only half their genes in common. Sociobiology developed out of such ideas in the 1970s & 80s and became very controversial<. Some people hate it because they have it mixed up with sociology, but sociologists mostly hate the idea of genetically-caused behavior. #7) Among many studies related to sociobiology:
Child-murder is much more common among step-parents!
Male lions taking over prides of lions tend to kill all the cubs.
More recently, the Naked Mole-Rat (of Somaliland and Kenya)
#8) Observing animal behavior in nature; some examples Stokes Nature Guides "In nature, all things are equally wild" -----
Gray Squirrel Sciurus carolinensisEach individual squirrel has a fixed home range, of a few wooded acres.These ranges overlap (they don't drive each other out, as is true of the home ranges of many other animals, & many birds) However, they have a strict dominance hierarchy; a pattern in which they give in to one another, without much fighting. Each knows his place Older/younger Male/female Young squirrels fight to gain rank in this hierarchy, with 2 periods of increased fighting: in late spring; and mid-late summer, or early fall. (during which time more are killed on roads, as young disperse) Aggressive interactions: tooth chatter; waving of tail; chase, but rarely actually fight. Nests: carrying leaves etc. In forks of trees. Mating chase : may go 1/4 mile or further from home range, both males and females make chuff sound; like a stifled sneeze Gestation period: 45 days weaned 8 to 9 weeks after birth; leave mother entirely at about 4 months -----
Box turtle Terrapene carolinaIndividual variations in color (yellow-reddish) and patternMale red iris in eye females have brown eyes Males have concave bottom shell female plastron is flat. Hibernate from Oct-April by digging into the ground, wedged tight in the dirt 3 or 4 inches under the surface. Eat insects, berries, slugs, carrion; Babies tend to be more carnivorous than adults Small home ranges, as little as 80 to 300 feet across; or less But do not drive others out of home ranges, although males tend to fight, and tend to have a hierarchy, in which the winner between any given pair is always the same, & the loser just closes up in his shell and waits for the other one to go away. Courtship of females by males: Craning of neck; nipping at females feet; male climbs on females back from the rear, tips self up at a 90 degree angle. Female can store sperm for up to 4 years from last mating: (in other kinds of turtles, this can be as long as 10 years!) Female digs nest in dirt with her hind feet (without looking!). She does this in late afternoon, continuing into evening. Lays 3 to 5 eggs, rarely 6 or 7. Eggs tend to be laid in May and June, but can be later in year. Digs several false nests, which she then abandons; When eggs are laid, then the dirt is packed in tightly over them. Eggs take 2 or 3 months to hatch; and sometimes the babies don't dig out until the next spring. Often live over 100 years, if not killed on the highway. -----
Mallard Duck Anas platyrhynchos(This is the widespread and numerous species of duck with the green iridescent heads, and the whitish ring around the collar: although only the males have that color: the females are brown with white flecks, and might seem to be a completely different kind of duck;Members of both sexes gradually shed their feathers several times per year (molting), and during one period, the males have the female color pattern) Mallard courtship is mostly a set of displays done between a male and a female, or among groups of males. "Three or more males perform intricate movement patterns almost simultaneously" "Subtle and last only a few seconds" The sounds made by the two sexes are completely different: only the females quack? Only males make "a nasal Rhaeb sound and a short Whistle-call" (the latter part of mating)
During mating (April-May) a territory is briefly defended, that does NOT include the nest site! MALE ONLY DISPLAYS Head Shake and Tail Shake done first, gets females attention Grunt-Whistle : arch body, with neck raised and head down Whistle-call Just after spitting out an arc of water droplets "Done by small groups of males, often simultaneously, in front of a female" Down-Up Whistle-call and/or Rhaebrhaeb call Head-Up-Tail-Up Whistle-call FEMALE ONLY DISPLAYS Inciting swim behind male, while repeatedly flicking bill back on one side of body: As she does this, she makes the inciting-call: "a rapid series of short percussive notes: "quegegegegegegege"
Persistent-Quack while trying to chose a nest site DISPLAYS DONE BY BOTH MALES AND FEMALES: Nod-Swimming Mock-Preening
"Pumping" rhythmic bobbing of head up and down, ----------
Questions that you should be able to answer about animal behavior:a) Can genetic differences cause differences in the behavior of animals? What is a specific example in fruit flies?b) Is alcoholism believed to be partly caused by genes? How did scientists distinguish between effects of family environment as opposed to genetic effects? c) Did the studies indicate that there are more than one kind of gene that affects alcoholism? d) What is an example of an altruistic behavior in an animal? e) Can instincts evolve even though the behaviors that they produce cause increased risks of being killed in those animals carrying the gene that promotes that behavior? f) What is the distinction between "inclusive fitness", as opposed to fitness? g) A parent has (on the average) at least what fraction of the same genes as one of their child? What fraction of are genes are shared by siblings (brothers and sisters, who have the same pair of parents)? What fraction are shared by grandchildren? What fraction are shared by first cousins (whose parents are siblings)? h) In relation to "Hamilton's law" what is meant by "the coefficient of relatedness". Why is the coefficient of relatedness 0.5 for siblings? What is the coefficient of relatedness for first cousins? (1/8 = 0.125) i) In Hamilton's law, what are the expected algebraic relations between the benefits and costs of altruistic behaviors? Which one needs to be larger in order to favor evolution of a gene causing instincts to behave in some way that is dangerous for the individual carrying out this behavior? j) What is meant by "social insects", as opposed to other kinds of insects; and what are the 4 kinds of social insects? *k) Do any of these belong to the order Hymenoptera? What peculiarity of the Hymenoptera seems to predispose to increased evolution of extreme altruistic behavior? l) Can evolution ever favor the evolution of instincts to harm certain other members of one's own species? m) What is so interesting about "Naked Mole-rats"? n) What is meant by a "home range" in wild animals? o) Do all kinds of animals tend to expel other members of their species from their home range? p) What are some specific examples of species that do not try to expel or keep out other members of their species? q) In species that don't try to expel others of the same species, what tends to happen instead? Do they just ignore each other? Or do they fight to the death? Or what? r) If you seen two squirrels facing each other and waving their tails, what is probably going on? What kind of noise do they tend to make in this case. s) What is the "mating chase" in Gray Squirrels? t) Describe nest building in Box Turtles. (Actually, it is pretty much the same in ALL species of turtles.) u) What is the duck that has the pretty dark green neck? (The common name, not the Linnean name, is sufficient here) v) Do both sexes have this color pattern? Do both sexes quack? w) In this kind of duck, what is somewhat surprising about the locations of their nests relative to the location of the territory from which they try to drive out others of the same species? x) When males of this species are courting females, describe what they do? How does the female signal to her chosen male that she has chosen him? *y) In some species of fish, the male guards the nest and the eggs; in other species, the nest is guarded by the female. In fish with external fertilization, it tends to be much more common for the nest to be guarded by the father, rather than the mother; whereas female guarding of the nest occurs mostly in species with internal fertilization? In terms of genes for behavior, try to figure out why this is to be expected. **z) In wild songbirds, the warning call is the same in many different species ("Look out for the hawk! Pass it on"). In terms of Sociobiology, would you have expected that each species would have its own, special, warning call? Or not? Arguments can be made either way: so the real question is, what are some relevant factors?
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