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Animal behavior
 

Animal behavior

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  • Bias:the difference between the expectation value of an estimator and the true value.
  • Arrive in Hawaii Aug to late April; feed in Hawaii and return to Alaska in the spring for breeding Kolea- Hawaiian name
  • Research indicates that humpbacks may use acoustical cues, currents and temperature changes, and even the earth's magnetic field to "home in " on their breeding and feeding grounds
  • The bower is a cone-shaped hut -like structure some 100 cm high and 160 cm in diameter, with an entrance usually propped up by two column-like sticks. A front "lawn" of some square meters area is cleaned of debris and laid out with moss . On this, and in the entrance of the bower, decorations such as colourful flowers or fruit, shining beetle elytra , dead leaves and other conspicuous objects are collected and artistically arranged. Males go to great lengths to ensure that their displays are in prime condition, replacing old items as needed, as well as trying to outdo their neighbours by finding more spectacular decorations, and arranging them appropriately. As opposed to other species of bowerbirds, such as the Satin Bowerbird , there is no fixed preference for items of a certain colour, more important being the "novelty value" of the items instead, which can lead to fashion -like trends if males find rare or unusual items; such rare finds are prime targets for theft by neighboring males. Females visit bowers and, depending on whether they like the "treasure trove" on display, will mate with the attendant males. The bower, indeed the male, play no part in nesting and raising the young. The songs and mimicry skill of this bird are well known among the indigenous peoples . In September 1872, Odoardo Beccari became the first naturalist to see the home grounds of this bowerbird in the Arfak Mountains of Irian Jaya. Because of its unadorned and plain plumage, this bowerbird is relatively safe from persecution. A common species within its limited habitat range, the Vogelkop Bowerbird is evaluated as Least Concern on the IUCN Red List of Threatened Species.
  • Eusociality and Reproduction in the Naked Mole-Rat Gray Lyons   The Naked Mole-Rat is most commonly known as the only truly eusocial mammal.  Naked mole-rat colonies are similar to some eusocial insect colonies in the nature of the dominant breeding queen, but are unique by the existence of a limited number of breeding male individuals (Sherman et al ., 1992).  Generally, only one to three males in the colony are breeding, while the others are reproductively suppressed like the non-breeding females.  For the lay reader, eusocial behavior can best be related to ants or termites - where many individuals work selflessly to the benefit of a dominant queen.  Scientists usually define eusociality more specifically as the existence of reproductive altruism, overlap of adult generations, and permanent philopatry (Burda et al ., 2000).   Naked Mole Rats are characterized by  female dominance - namely a colony that is ruled by one breeding female and sustained by an army of monomorphic workers.  This breeding system is most closely characterized as polyandry (one female with many male mates) since the queen will copulate with one to three breeding males.  However, the breeding system may also be characterized as male monogymy since the males will mate only with a single queen.  Males generally follow an age-related hierarchy whereby the oldest males enjoy breeding rights with the female.  Due to the high levels of genetic relatedness, the males are largely non-competitive for reproduction.     In a recent study, researchers removed breeding males from a colony of naked mole-rats and monitored both behavioral and physiological signs to understand the fruition of select breeding males.  Although urinary levels of testosterone and cortisol were monitored, no correlation could be inferred from cortisol levels, but testosterone levels did correlate with dominance rank.  Additionally, age and size correlated with dominance rank.  The researchers noted, however, that virtually no aggressive interactions or other competitive manifestations occurred in the ascension of breeding males.  This lack of competition is surprising, considering the relatively hostile competition that exists among females to assume the queen position.  The authors attribute this discrepancy to either the “lower reproductive skew for males compared to females or queen control over male reproduction” (Clarke and Faulkes, 1998).   Female Naked Mole-Rats are more aggressive and will exert dominance to in the form of shoving behavior.  This behavior includes prolonged pushes involving nose to nose contact.  This aggression occurs within colonies and is mainly instigated by breeding individuals (generally one female and between one and three male individuals).  The prevailing theories explaining this behavior are the threat reduction hypothesis (that is, suppressing the reproduction in non-breeding individuals) and the work conflict hypothesis (that is, inciting work activity in non-breeding individuals).  In a recent article, the authors found no evidence to support the work conflict hypothesis, but they did note that the onset of shoving behavior coincided with reproductive activity and shoving strongly correlated with reproductive status.  Queen shoving may have several functions, but this report ads evidence to only one of those functions: augmenting the reproductive success of the queen and breeding male individuals (Clarke and Faulkes, 2001).   In accordance with the eusocial nature of naked mole-rats, the it would be expected that naked mole-rats recruit colony mate to food sources.  The successful forager attracts other colony members by auditory calls and displaying food (for scent, rather than sight).  The colony mates will follow the scout’s original route through the labyrinth of tunnels, even if shorter alternate routes exist.  However, if the route is replaced with clean tunnels, the colony mates showed no preference in routes to seek out the food, implicating the role of olfaction in food recruitment (Judd and Sherman, 1996).     It is easy to speculate on the evolutionary origins of the eusocial behavior of the Naked Mole-Rat.  Presumably, the evolution of kin selection is inextricably tied to the subterranean habitiat: an ancestral rodent species found that they could escape some of the predation inherent in burrowing by closing the top of the burrow to surface predators.  This habitiat led to rampant in breeding which produced individuals with high genetic similarity such that kin selection was more benefitial than individuality in the colony (Sherman et al ., 1991).  The intracolony genetic relatedness has been confirmed in a recent study, which explains the evolution of reproductive altruism.  The same study also has implications predicting the intrercolony aggression described in Basic Biology and Habitat of the Naked Mole-Rat.   Faulkes et al . (1997) used a variety of genetic tests available in 1997 to quantify the level of genetic divergence in the naked mole-rats.  Multilocus DNA fingerprinting was performed using restriction endonucleases and sequence-specific minisatellite probes.  In addition, mtDNA regions, including the conserved cytochrome-b sequence, were sequenced and manually read by polyacrylamide gel electrophoresis.  Thereafter, the data were analyzed by computer algorithms to construct unrooted phylogenetic trees. The authors found the individuals within a single colony to be nearly monomorphic to the point where they observed “a single individual can be representative of the whole colony.”  Conversely, the authors observed a more divergent macrogenetic structure among the various colonies they tested in Ethiopia, Somalia, and Kenya.  These results may be expected considering the secluded nature of naked mole-rat colonies and their documented propensity for eusocial inbreeding.   While the many behavioral attributes of Naked Mole-Rat reproduction are interesting, the species is unique in other areas.  They are known to defy many common assumptions regarding mammalian biology.  Some of these characteristics are addressed in the next section, Assorted interesting Facts About the Naked Mole-Rat.    

Animal behavior Animal behavior Presentation Transcript

  • Animal Behavior By:saif BS zology
  • • Behavior is what an animal does and how it does it. What is Behavior? • Animal behavior asks what, why, and how. • Animal behavior is also referred to as ethology. – Scientists who study animal behavior are called ethologists.
  • • Animal behavior is centered around the ability to move. – Animals seek food, water, shelter. – Animals play with each other. – Animals seek mates. Introduction
  • Introduction • Why do animals do what they do? – Why do birds sing? – How do sea turtles navigate the ocean to lay their eggs on the same beach where they were hatched? – How do honeybees know when the hive needs more food? Image from http://www.nps.gov Image from http://www.scottcamazine.com
  • Introduction • Behavior results as a reaction to a stimulus. – A stimulus is a detectable change in the animal’s internal or external environment. – Hunger. – Sound. – Pain. – Visual cues(stimulus). – Hormonal changes. Image from http://www3.nau.edu/biology/
  • Introduction • Ethologists do not attempt to describe WHY an animal does a behavior before describing WHAT the animal is doing. – This removes as much bias as possible – good scientists don’t want to just “see what they want to see”. – Need to make objective observations of animal behaviors, analyze the data statistically, then come to conclusions about WHY an animal behaves a certain way.
  • Introduction • For example, you see two cubs interacting with each other, rolling and hopping around, running to and from each other. – As a behavioral ecologist, you would first state the behavior you are observing. – Once you made the observations about WHAT was happening, you could begin to determine WHY they are behaving that way.
  • Introduction • The behavior you observed could have been many different things. – Play. – Mating rituals. – Aggression, defending territory.
  • How to determine WHY – action patterns. • Action patterns are complex behaviors that are always repeated the same way by a species of animal. – We say that action patterns are stereotyped, since they occur the same way each time, and through to completion. – After repeatedly observing action patterns, an ethologist can analyze the data statistically. – (Statistics is the study of the collection, organization, analysis, interpretation and presentation of data) – Only then do we attempt to determine WHY a behavior is being done. – Fixed Action Patterns (FAP) are INNATE
  • Niko Tinbergen(Dutch) • Niko Tibergen(noble prize holder) was a pioneer(first to do something) in the field of ethology and ornithology. – He observed animals in their natural conditions, then manipulated(handle something), or varied the conditions to see how the animals responded.Image from http://nobelprize.org/
  • Niko Tinbergen • Tinbergen observed how a wasp called the beewolf finds its nest among other beewolf nests. – He observed that the beewolf would circle its nest in an ever-widening circle before flying away to hunt. – This behavior was an action pattern – it was performed exactly the same way each time. Image from http://www.sciencenews.org
  • Niko Tinbergen • After the beewolf flew off, Tinbergen would move certain landmarks around the nests. • When the beewolf returned, it was disoriented. – So, by manipulating the beewolf’s environment, Tinbergen came to the conclusion that the beewolf commits landmarks to memory to be able to find its nest when it comes back from hunting! Image from http://www.earthlife.org
  • Niko Tinbergen • Tinbergen had to describe and investigate WHAT the organism was doing before attempting to explain WHY.
  • More on Action Patterns • The egg-rolling behavior of the greylag goose is a good example of an action pattern. • Niko Tibergen and another pioneer in ethology, Konrad Lorentz, originally observed this behavior. Image from http://www.grayimages.co.uk
  • More on Action Patterns • The goose will roll an egg that is outside the nest back into the nest in the same manner every time. – Interestingly, the goose will do this with any round object placed outside the nest! – Every time this action pattern is initiated, it is carried through to completion.
  • Proximate vs. Ultimate Causes • The question of “WHY” can have different answers. • Proximate causes are related to internal changes in the animal. – Hormones. – Messages from the nervous system. • “Proximate” means close. • Ultimate causes are related to the survival and reproductive success of the animal. • “Ultimate” means furthest, or utmost.
  • Proximate vs. Ultimate Causes • An example incorporating both proximate and ultimate causes: Belding’s ground squirrels. – When males reach about two months old, they leave the burrow where they were born. • It is an increase in testosterone, or a hormonal change that triggers this behavior. • So, the proximate cause of the nest- leaving behavior involves the increase in testosterone levels in the squirrel.
  • Proximate vs. Ultimate Causes • There is more to the story than just hormones! – When males leave the nest, they avoid inbreeding with sisters or cousins, etc. – Their offspring are therefore healthier. – The male offspring inherit the same genetic information that induces them to leave their nests at a young age. – So, this behavior is passed on genetically, and it makes for a healthier population of squirrels. – Avoiding inbreeding is therefore the ultimate cause of this “early nest-leaving” behavior.
  • Ecology: Interaction between organisms and the biotic and abiotic environment • Abiotic- non living; e.g., temperature, light, dissolved gas, water • Biotic- living; e.g., predators, prey, mates Behavioral Ecology The study of the behavior of organisms within an evolutionary framework. • e.g., communication, finding food, protection from predators
  • Mechanistic basis for behavior: A. Identify the stimuli that triggers the behavior or B. Study the psychological, neuronal, and hormonal changes that underlie the behavior E.g., MIGRATION Hawaii Distribution & Migration Map of Pacific Golden Plover
  • Proximate causes • External stimuli- changes in day length and temp • Internal stimuli - hormone levels Winter plumage Breeding plumage
  • Ultimate causes - address the evolutionary significance for a behavior and why natural selection favors this behavior. • Why did a behavior evolve? • Is it adaptive? • Does it contribute to reproductive success? Example: birds that migrate have a selective advantage over birds that don't/didn't, selected for over time, could be due to long term climate changes, glaciation, disease, taking advantage of food sources, etc.
  • Nature versus Nurture: Revisiting an Old Debate Nature Behaviors are: • Innate • Hard-wired • Instinctual • Genetically determined Nurture Behaviors are: • Learned • Flexible • Not genetically determined Behavior results from both genes and environmental factors
  • A. Behavior - What an animal does and how it does it. - some behavior is learned, some behavior is inherited B. To some extent ALL behavior has a Genetic Basis 1. some is totally genetic - which implies heritable 2. some is learned but relies ENTIRELY on genetically based mechanisms C. In general, behavior is a response to some environmental stimulus
  • Innate Behaviors – inherited, instinctive A. programmed by genes; B. highly stereotyped (similar each time in many individuals) C. Four Categories 1. Kinesis 2. Taxis 3. Reflex 4. Fixed Action Pattern
  • 1. Kinesis: "change the speed of random movement in response to environmental stimulus“ 2. Taxis: "a directed movement toward or away from a stimulus; positive and negative taxes 3. Reflex: "movement of a body part in response to stimulus". 4. Fixed Action Pattern (FAP): "stereotyped and often complex series of movements, responses to a specific stimulus", hardwired, however, not purely genetic, may improve with experience a. programmed response to a stimulus b. stimulus of FAP = "releaser", sometimes called "sign stimulus“ c. examples: - courtship behavior - rhythms - daily (circadian); annual (circannual)
  • D. Characteristics of Innate Behaviors - especially FAPs: 1. The behavior is performed correctly the 1st time without prior experience (no opportunity to learn) 2. Triggered by some external stimulus 3. Once started, run to completion with no further input 4. Breeding crosses produce hybrid behaviors
  • • Ethology is the study of how animals behave in their natural habitat. –Karl von Frisch: bee communication –Niko Tinbergen: herring gull experiment; digger wasps –Konrad Lorenz: imprint in geese Classical ethology presaged an evolutionary approach to behavioral biology
  • Karl Von Frisch- communication in bees
  • Herring gull experiment by Niko Tinbergen Releaser Stimuli- stimuli that release FAP E.g., Chick and red dot on gull parents beak triggers feeding response- parent regurgitates food Laysan albatross feeding chick
  • Niko Tinbergen Hypothesis: digger wasps use visual landmarks to keep track of her nests Move pine cones Visual cue is arrangement pattern rather than objects themselves
  • Egg rolling behavior in geese is a Fixed Action Pattern
  • Male three-spined stickleback shows aggression at models with red undersides Life-like model
  • • Songbird repertoires provide us with examples. –Why has natural selection favored a multi-song behavior? Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 51.5
  • • It may be advantageous for males attracting females. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 51.6
  • • Cost-benefit analysis of foraging behavior. –Foraging is food-obtaining behavior. • The optimal foraging theory states that natural selection will benefit animals that maximize their energy intake-to-expenditure ratio. Height of Drop (m) Average Number Of Drops Required to Break Shell Total Flight Height (Number of Drops × Height per Drop) 2 55 110 3 13 39 5 6 30 7 5 35 15 4 60
  • Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 51.7
  • • The behavior is adaptive - signs that natural selection is at work a. survival may depend on behavior, learning not an option (one chance only) b. animals with simple NS may not have capacity to learn - not strictly true, "simple" animals learn c. social interactions dependent on survival require rigid performance of roles mating rituals, termite mounds
  • Learning - Learned Behavior: Five Categories A. Imprinting 1. a strong association learned during a specific developmental period a. "sensitive period" or "critical period" b. imprinting of baby geese on mother - Lorenz baby geese imprint on mother within hours of hatching will imprint on any object during that period 2. learning a releaser for an innate FAP
  • Goose imprinting by Conrad Lorenz Geese imprint on the first moving (with sound) object that they see after birth There is a selection of a specific period of time (critical period) for social attachment and mate recognition in geese (to ensure geese imprint on the same species)
  • Imprinting in conservation biology: Need to minimize/eliminate human presence while raising California Condors
  • B. Habituation 1. decline in response to a harmless, repeated stimulus filter - prevents animal from wasting energy/attention on irrelevant stimuli adaptive
  • C. Conditioning - laboratory setting 1. classical conditioning animals make associations - Pavlov's dog associates bell with food, begins to salivate, can be extinguished and later followed by recovery (unconditioned stimulus - meat, unconditioned response - salivation, conditioned stimulus - bell, conditioned response - salivation) a. animal learns to perform an "old" response to a new stimulus b. Pavlov's dog - place dried meat powder in dog mouth - salivation - associate with bell - salivation to bell c. Stimulus first, behavior second (but of course there is an expectation of reward second)
  • 2. operant conditioning a. perform behavior to receive reward or avoid punishment b. Skinner Box - levers, reward - self training elaborate protocols c. behavior first, reward second (but of course there is a stimulus, if only a thought of reward)
  • • Operant conditioning. –This is called trial-and-error learning - an animal learns to associate one of its own behaviors with a reward or a punishment.
  • D. Trial and Error Learning - nature setting 1. natural operant conditioning 2. modify responses to specific stimuli (releasers) - making both more adaptive 3. modify releaser to specific FAP - making both more adaptive Observational learning - social imitation
  • Octopus opening jar with crab Trial & Error & Observational Learning
  • • Play as a behavior has no apparent external goal, but may facilitate social development or practice of certain behaviors and provide exercise. Practice and exercise may explain the ultimate bases of play
  • E. Insight, reasoning 1. manipulating concepts in the mind to arrive at adaptive behavior 2. mental trial-and-error 3. internal memory stores are used as additional sensory/information source All examples of tool-using: • chickadees/tits and opening milk bottles • Egyptian Vulture - uses rocks • Cocos Finch - uses splinters of wood • North American Gulls, Northwestern Crow - smash clams on sandy beaches
  • • Cognition is the ability of an animal’s nervous system to perceive, store, process, and use information gathered by sensory receptors. The study of cognition connects nervous system function with behavior
  • • Migration Behavior. –Migration is the regular movement of animals over relatively long distances. –Piloting: an animal moves from one familiar landmark to another until it reaches its destination. Whale Migration Routes
  • • Orientation: animals can detect directions and travel in particular paths until reaching destination. – Navigation may use cues including the earth’s magnetic field, the sun, and the stars. starlings Adults who made the trip before Juv. went W & SW Normal Migration Transport adult and juv.
  • • Social behavior is any kind of interaction between two or more animals, usually of the same species. Sociobiology places social behavior in an evolutionary context Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Orcas chasing Dusky DolphinOrca and Weddell Seal
  • Social Behavior in Vertebrates A. Predator Avoidance Behavior -mimicry - schooling B. Reproductive Behavior -competition -territoriality - displays C. Parental Behavior D. Communication E. Cooperative Behavior -warning alarms
  • • Sometimes cooperation occurs. Competitive social behaviors often represent contests for resources Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 51.18
  • • Agonistic behavior is a contest involving threats. – Submissive behavior. – Ritual: the use of symbolic activity. – Generally, no harm is done. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 51.19
  • • Reconciliation behavior often happens between conflicting individuals. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 51.20
  • • Dominance hierarchies involve a ranking of individuals in a group (a “pecking order”). –Alpha, beta rankings exist. • The alpha organisms control the behavior of others. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  • • Territoriality is behavior where an individual defends a particular area, called the territory. –Territories are typically used for feeding, mating, and rearing young and are fixed in location.
  • –Drawbacks are that territoriality uses a great deal of an individual’s energy. • In addition, an individual might be defending a territory and die or miss a reproductive opportunity. –Spraying behavior is where an individual marks its territory. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 51.22
  • • Courtship behavior consists of patterns that lead to copulation and consists of a series of displays and movements by the male or female. Natural selection favors mating behavior that maximizes the quantity or quality of mating partners Vogelkop Bowerbird
  • Fig. 51.23
  • • Parental investment refers to the time and resources expended for raising of offspring. – It is generally lower in males – Females usually invest more time into parenting (fecundity, egg size, care of offspring) – Females are usually more discriminating in terms of the males with whom they choose to mate. • Females look for more fit males (i.e., better genes), the ultimate cause of the choice. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  • • Mating systems differ among species. – Promiscuous: no strong bond pairs between males and females. – Monogamous: one male mating with one female. – Polygamous: an individual of one sex mating with several of the other sex. • Polygyny where a single male mates with many females. • Polyandry one female mates with several males. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  • • Certainty of paternity can influence mating systems and parental care. –If the male is unsure if offspring are his, parental investment is likely to be lower. –Exceptions do exist. Male sea spider cares for eggs
  • Mimicry monarch viceroy Bastian Mimicry- palatable species resembles an unpalatable one Mullerian- two or more unpalatable species resembles one another monarch queen
  • blenny (Aspidontus taeniatus) mimics Hawaiian cleaner wrasse shortnose wrasse mimics Potter's angel which sports a defensive spine Mimicry
  • Schooling Behavior
  • • Defining animal signals and communication. – A signal is a behavior that causes a change in the behavior of another animal. – The transmission of, reception of, and response to signals make up communication. – Examples include the following: • Displays such as singing, and howling. • Information can be transmitted in other ways, such as chemical, tactile, electrical. Social interactions depend on diverse modes of communication Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  • – Pheromones are chemicals released by an individual that bring about mating and other behaviors. • Examples include bees and ants. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 51.26
  • • Most social behaviors are selfish, so how do we account for behaviors that help others? –Altruism is defined as behavior that might decrease individual fitness, but increase the fitness of others. The concept of inclusive fitness can account for most altruistic behavior Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 51.28
  • Altruism
  • Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 51.29
  • –Inclusive fitness: How can a naked mole rat enhance its fitness by helping other members of the population? • How is altruistic behavior maintained by evolution? • If related individuals help each other, they are in affect helping keep their own genes in the population. • Inclusive fitness is defined as the affect an individual has on proliferating its own genes by reproducing and helping relatives raise offspring. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  • –Hamilton’s Rule and kin selection. • William Hamilton proposed a quantitative measure for predicting when natural selection would favor altruistic acts. • Hamilton’s rule states that natural selection favors altruistic acts. Worker bees
  • • The three key variables are as follows: – B is the benefit to the recipient – C is the cost to the altruist – r is the coefficient of relatedness, which equals the probability that a particular gene present in one individual will also be inherited from a common parent or ancestor in a secondCopyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 51.30
  • –The rule is as follows: Formally, such genes should increase in frequency when rB > C The more closely related two individuals are, the greater the value of altruism. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  • – Kin selection is the mechanism of inclusive fitness, where individuals help relatives raise young. – Reciprocal altruism, where an individual aids other unrelated individuals without any benefit, is rare, but sometimes seen in primates (often in humans).
  • Sociobiology connects evolutionary theory to human culture Fig. 51.32