AP Biology Animal Behavior

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Animal behavior:

Animal behavior The inside scoop on why animals do what they do.

Why animals behave they way they do:

Why animals behave they way they do Behavior depends on a number of variables that fall into four categories Solitary Social Fixed Variable Behavior- an action carried out by muscles under control of the nervous system in response to stimulus Essential for: obtaining nutrients, finding a sexual partner and survival

How do we discover behaviors:

How do we discover behaviors In order to understand behaviors answer these four questions What stimulus elicits the behavior, and what physiological mechanisms mediate the response? How does the animal’s experience during growth and development influence the response? How does the behavior aid survival and reproduction? What is the behavior’s evolutionary history? The first two questions are the Proximate cause (how a behavior occurs or is modified) The second two are the Ultimate cause (why a behavior occurs in the context of natural selection)

The red stickleback:

The red stickleback Male stickleback fish have red under bellies while the females do not, and are very territorial When males see the color red they become aggressive and will attack the red color, be it another male or an unrealistic model The purpose for this is to invade other breeding areas and to protect their own territory

The red Stickleback (con):

The red Stickleback (con) This territorial response from the males is known as a Fixed Action Pattern (a sequence of unrelated acts directly linked to a simple stimulus) These behaviors are essentially unchangeable Once these behaviors are started, normally continued to completion The Sign Stimulus is the external trigger for the behavior In this case it is the red belly of the male stickleback

Environmental stimuli:

Environmental stimuli These can trigger behaviors or also provide cues for animals to carry out behaviors A well know environmental stimulus is the change of seasons causing birds to Migrate (a regular, long-distance change in location) Some animals track position relative to the sun, despite its changes throughout the day This is achieve through a Circadian Clock (an internal mechanism that maintains a 24-hour activity rhythm or cycle)

Animal movements are under substantial genetic influence:

Animal movements are under substantial genetic influence Kinesis- a simple change in activity or turning rate in response to stimulus Sow bugs are more active in dry areas and less active in humid areas Increases the chance that the bugs will leave a dry area for a moist area Taxis- automatic, oriented movement toward or away from stimulus Stream fish show positive rheotaxis , automatically swimming upstream, the current being the stimulus This keeps fish facing the way food is coming and prevents them from being swept away

Communication is key:

Communication is key Social interaction between animals relies on transmitting information through specialized behaviors called signals Signal- a behavior that causes change in another animal’s behavior Can be visual, auditory, chemical, tactile, and electrical Some communication is under heavy genetic control Many signals are energy efficient The environment makes a significant contribution to all communication systems

The environment influences development of behaviors:

The environment influences development of behaviors The environment modifies many behaviors One of the most powerful ways environmental conditions can modify behavior is through learning Habituation- a loss of responsiveness to unimportant stimuli that do not provide appropriate feedback Ex: animals stop responding to warning signals if the signals are not followed by a predator attack

Fitness may be enhanced by capacity for spatial learning:

Fitness may be enhanced by capacity for spatial learning Environments have spatial variation it may be advantageous for animals to modify their behavior based on experience with the spatial structure of the environment Including food, hazards, prospective mates etc. Some animals are able to form cognitive maps (internal codes of spatial relationships of objects in their environment)

Associative learning:

Associative learning Associative learning- ability of animals to associate one stimulus with another Ex: A bird gets food poisoning from a colorful bug and learns to avoid those kinds of bugs Classical conditioning- a learning process when two stimuli are continuously paired Operant conditioning- an animal learns to associate one of its behaviors with a reward or a punishment

Connecting behavior with the nervous system:

Connecting behavior with the nervous system The study of cognition connects these two Cognition- the ability of an animal’s nervous system to perceive, store, process and use information gathered by sensory receptors

Behavioral traits can evolve by natural selection:

Behavioral traits can evolve by natural selection Genes influence behavior Natural selection controls what genes get passed down Natural selection determines what behaviors are passed down through genes Behavioral differences between closely related species are common When behavioral variation within a species corresponds to variation in environmental conditions, may be evidence of past evolution Well known example of this is prey selection of garter snakes Costal garter snakes feed on salamanders, frogs, toads and mainly slugs Inland garter snakes feed on frogs, leeches, and fish but not slugs

Natural selection favors behaviors that increase survival :

Natural selection favors behaviors that increase survival The two most direct ways that behavior can affect fitness are through influences on foraging and mate choice. Optimal foraging theory (OFT)- foraging behavior as a compromise between the benefits of nutrition and costs of obtaining food Energy expenditure versus the risk of predation while foraging Natural selection favors foraging that minimizes the costs of foraging and maximizes the benefits

…and reproductive success:

…and reproductive success Mating relationship between males and females varies a great deal from species to species Many species are promiscuous with no strong pair-bond or lasting relationships In monogamous species the mates remain together for a longer period of time Polygamous species have one individual with many partners Polygyny- one male with many females Polyandry- one female with many males In a monogamous species males and females are hard to distinguish between Certainty of paternity can influence the mating systems and parental care If a males is unsure then his parental influence is likely to be lower

Sexual selection:

Sexual selection Sexual dimorphism within a species results from sexual selection A form of natural selection in which differences in reproductive success among individuals are a consequences of differences in mating success Mate preferences in females may play a central role in the evolution of male behavior and anatomy through intersexual selection

Game theory can model behavior:

Game theory can model behavior Game theory evaluates alternative strategies in situation where the outcome depends on each individual’s strategies and the strategies of other individuals

Inclusive fitness:

Inclusive fitness Most social behaviors are selfish, meaning that they benefit the individual at the expense of others, especially competitors Behavior that maximizes an individual’s survival and reproductive success is favored my natural selection, regardless of how it affects other individuals Altruism- behavior that appears to decrease individual fitness but increases fitness of others Belding’s ground squirrels give high-pitched alarm calls when predators are approaching causing other squirrels to retreat to burrows The caller brings the predator’s attention to itself and has a greater risk of being killed Inclusive fitness is defined as the effect an individual has on proliferating its own genes by reproducing and helping relatives raise offspring

Inclusive fitness (cont.):

Inclusive fitness (cont.) Hamilton’s rule- conditions under which altruistic acts will be favored by natural selection Three key variables The benefit to the recipient is B The cost to the altruist is C The coefficient of relatedness is r, which equals the probability that a particular gene present is one individual will also be inherited from a common parent or ancestor in a second individual rB >C The more closely related two individuals are, the greater the value of altruism

Learning through observing others:

Learning through observing others Social learning- learning through observing others This type of learning forms the roots of culture (a system of information transfer through social learning or teaching) Cultural transfer of information has the potential to alter behavioral phenotypes and influence the fitness of individuals This is not restricted to humans

Social behavior in evolution:

Social behavior in evolution Human culture is related to the evolutionary theory in the discipline of sociobiology Main premise of sociobiology is that certain characteristics exist because they are expressions of genes that have been perpetuated by natural selection Spectrum of human social behaviors may be influenced by our genetic makeup The human capacity for learning allows human behavior to be more easily molded than that of other animals

Congratulations you made it!:

Congratulations you made it!

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