CAMPBELL BIOLOGY IN FOCUS Urry Cain Wasserman Minorsky
CAMPBELL BIOLOGY IN FOCUS Urry • Cain • Wasserman • Minorsky • Jackson • Reece 39 Motor Mechanisms and Behavior Lecture Presentations by Kathleen Fitzpatrick and Nicole Tunbridge © 2014 Pearson Education, Inc.
Part 1: Motor Mechanisms: Muscular System §Does the actions of the muscular system belong to the CNS or the PNS? §What specific branch(es) does it belong to? §HW: watch the bozeman video on “the muscular system” under anatomy and physiology and make a concept map for the muscular system © 2014 Pearson Education, Inc.
The relationship between behavior and muscular system: § A behavior is an action carried out by muscles under control of the nervous system © 2014 Pearson Education, Inc.
Vertebrate Skeletal Muscle § Vertebrate skeletal muscle moves bones and the body and is characterized by a hierarchy of smaller and smaller units § A skeletal muscle consists of a bundle of long fibers(fascicle), each a single cell, running parallel to the length of the muscle § Each muscle fiber is itself a bundle of smaller myofibrils, which contain thick and thin filaments © 2014 Pearson Education, Inc.
§ Muscle cell contraction relies on the interaction between protein structures § Thin filaments consist of two strands of actin coiled around one another § Thick filaments are staggered arrays of myosin molecules © 2014 Pearson Education, Inc.
The functional Unit: Sarcomere §Made up of actin and myosin proteins §Has bands at the end called Z lines © 2014 Pearson Education, Inc.
Figure 39. 2 Muscle Bundle of muscle fibers Nuclei Single muscle fiber (cell) Plasma membrane Z lines Myofibril Sarcomere TEM Thick filaments (myosin) Thin filaments (actin) © 2014 Pearson Education, Inc. Z line M line Sarcomere 0. 5 m Z line
Figure 39. 2 a Muscle Bundle of muscle fibers Nuclei Single muscle fiber (cell) Plasma membrane Z lines Myofibril Sarcomere © 2014 Pearson Education, Inc.
Figure 39. 2 b Sarcomere TEM Thick filaments (myosin) Thin filaments (actin) © 2014 Pearson Education, Inc. Z line M line Sarcomere 0. 5 m Z line
The Sliding-Filament Mechanism of Muscle Contraction § According to the sliding-filament model, filaments slide past each other longitudinally, causing an overlap between thin and thick filaments Video: Cardiac Muscle © 2014 Pearson Education, Inc.
Figure 39. 3 Relaxed muscle Z Sarcomere M Z Z M Z Contracting muscle 0. 5 m Fully contracted muscle Contracted sarcomere © 2014 Pearson Education, Inc.
How does this occur? § The sliding of filaments relies on interaction between actin and myosin § The “head” of a myosin molecule binds to an actin filament, forming a cross-bridge and pulling the thin filament toward the center of the sarcomere § Need ATP and calcium ions in order for this to occur § THINK: what roles do ATP and calcium play in this process? § Muscle contraction requires repeated cycles of binding and release © 2014 Pearson Education, Inc.
Figure 39. 4 1 Thin filaments Thick filament Thin filament Myosin head (low energy configuration) ATP 5 ATP 2 Thick filament Thin filament moves toward center of sarcomere. Actin ADP Myosin head (low energy configuration) ADP P ADP i 4 © 2014 Pearson Education, Inc. Myosinbinding sites Pi Pi Cross-bridge Myosin head (high energy configuration) 3
Figure 39. 4 a Thin filament 1 ATP Myosin head (low energy configuration) Thick filament © 2014 Pearson Education, Inc.
Figure 39. 4 b 2 Myosinbinding sites Actin ADP Pi © 2014 Pearson Education, Inc. Myosin head (high energy configuration)
Figure 39. 4 c 3 ADP © 2014 Pearson Education, Inc. Pi Cross-bridge
Figure 39. 4 d 4 Thin filament moves toward center of sarcomere. Myosin head (low energy configuration) © 2014 Pearson Education, Inc.
The Role of Calcium and Regulatory Proteins § The regulatory protein tropomyosin and the troponin complex, a set of additional proteins, bind to actin strands on thin filaments when a muscle fiber is at rest § How does this affect the sliding filament process? © 2014 Pearson Education, Inc.
Figure 39. 5 Ca 2 -binding sites Tropomyosin Actin Troponin complex (a) Myosin-binding sites blocked Ca 2 Myosinbinding site (b) Myosin-binding sites exposed © 2014 Pearson Education, Inc.
Role of Calcium ions: § For a muscle fiber to contract, myosin-binding sites must be uncovered § calcium ions (Ca 2 ) bind to the troponin complex and expose the myosin-binding sites § In order for contraction to occur, would you need high or low concentrations of Calcium ions? § What do you think might cause muscle contraction to stop? © 2014 Pearson Education, Inc.
Figure 39. 6 a Synaptic terminal T tubule Sarcoplasmic reticulum (SR) Axon of motor neuron Mitochondrion Myofibril Plasma membrane of muscle fiber Sarcomere © 2014 Pearson Education, Inc. Ca 2 released from SR
Figure 39. 6 Axon of motor neuron Synaptic terminal T tubule Sarcoplasmic reticulum (SR) Mitochondrion Myofibril Plasma membrane of muscle fiber Ca 2 released from SR Sarcomere 1 Synaptic terminal of motor neuron Plasma Synaptic cleft T tubule membrane ACh Sarcoplasmic reticulum (SR) 2 Ca 2 pump 3 Ca 2 ATP 4 CYTOSOL 7 6 Ca 2 5 © 2014 Pearson Education, Inc.
How do we control the release of calcium ions? § The stimulus leading to contraction of a muscle fiber is an action potential in a motor neuron that makes a synapse with the muscle fiber § The synaptic terminal of the motor neuron releases the neurotransmitter acetylcholine § Acetylcholine depolarizes the muscle § Is this an inhibitory or excitatory response? Animation: Muscle Contraction © 2014 Pearson Education, Inc.
Figure 39. 6 b 1 Synaptic terminal of motor neuron Synaptic cleft T tubule Sarcoplasmic reticulum (SR) 2 ACh Ca 2 pump 3 Ca 2 ATP 4 CYTOSOL 7 6 Ca 2 5 © 2014 Pearson Education, Inc. Plasma membrane
§ Action potentials travel to the interior of the muscle fiber along transverse (T) tubules, infoldings of the plasma membrane § The action potential along T tubules causes the sarcoplasmic reticulum (SR), a specialized endoplasmic reticulum, to release Ca 2 § The Ca 2 binds to the troponin complex on the thin filaments, initiating muscle fiber contraction © 2014 Pearson Education, Inc.
§ When motor neuron input stops, the muscle cell relaxes § Transport proteins in the SR pump Ca 2 out of the cytosol § Regulatory proteins bound to thin filaments shift back to the myosin-binding sites © 2014 Pearson Education, Inc.
Diseases of the muscular system: § Amyotrophic lateral sclerosis (ALS; also known as Lou Gehrig’s disease) interferes with the excitation of skeletal muscle fibers; this disease is usually fatal § Myasthenia gravis is an autoimmune disease that attacks acetylcholine receptors on muscle fibers; treatments exist for this disease © 2014 Pearson Education, Inc.
Nervous Control of Muscle Tension § Contraction of a whole muscle is graded, which means that the extent and strength of its contraction can be voluntarily altered § There are two basic mechanisms by which the nervous system produces graded contractions § Varying the number of fibers that contract § Varying the rate at which fibers are stimulated © 2014 Pearson Education, Inc.
§ In vertebrates, each motor neuron may synapse with multiple muscle fibers, although each fiber is controlled by only one motor neuron § A motor unit consists of a single motor neuron and all the muscle fibers it controls © 2014 Pearson Education, Inc.
Figure 39. 7 Spinal cord Motor unit 1 Motor unit 2 Synaptic terminals Nerve Motor neuron cell body Motor neuron axon Muscle fibers Tendon © 2014 Pearson Education, Inc.
Figure 39. 8 Tension Tetanus Summation of two twitches Single twitch Action potential © 2014 Pearson Education, Inc. Time Pair of action potentials Series of action potentials at high frequency
§ Tetanus is a state of smooth and sustained contraction produced when motor neurons deliver a volley of action potentials © 2014 Pearson Education, Inc.
Types of Skeletal Muscle Fibers § There are several distinct types of skeletal muscles, each of which is adapted to a particular set of functions § They are classified by the source of ATP powering the muscle activity and the speed of muscle contraction © 2014 Pearson Education, Inc.
Table 39. 1 © 2014 Pearson Education, Inc.
§ Oxidative and glycolytic fibers are differentiated by their energy source § Oxidative fibers rely mostly on aerobic respiration to generate ATP § These fibers have many mitochondria, a rich blood supply, and a large amount of myoglobin § Myoglobin is a protein that binds oxygen more tightly than hemoglobin does © 2014 Pearson Education, Inc.
§ Glycolytic fibers use glycolysis as their primary source of ATP § Glycolytic fibers have less myoglobin than oxidative fibers and tire more easily § In poultry and fish, light meat is composed of glycolytic fibers, while dark meat is composed of oxidative fibers © 2014 Pearson Education, Inc.
§ Fast-twitch and slow-twitch fibers are differentiated by their speed of contraction § Slow-twitch fibers contract more slowly but sustain longer contractions § All slow-twitch fibers are oxidative § Fast-twitch fibers contract more rapidly but sustain shorter contractions § Fast-twitch fibers can be either glycolytic or oxidative © 2014 Pearson Education, Inc.
§ Most human skeletal muscles contain both slowtwitch and fast-twitch muscles in varying ratios § Some vertebrates have muscles that twitch at rates much faster than human muscles § In producing its characteristic mating call, the male toadfish can contract and relax certain muscles more than 200 times per second © 2014 Pearson Education, Inc.
Figure 39. 9 © 2014 Pearson Education, Inc.
Other Types of Muscle: Cardiac and Smooth § Cardiac muscle, found only in the heart, consists of striated cells electrically connected by intercalated disks § Cardiac muscle can generate action potentials without neural input § In smooth muscle, found mainly in walls of hollow organs such as those of the digestive tract, contractions are relatively slow and may be initiated by the muscles themselves § Contractions may also be caused by stimulation from neurons in the autonomic nervous system © 2014 Pearson Education, Inc.
§ SLIDES ON SKELETONS are FYI § Not tested too much on the AP exam © 2014 Pearson Education, Inc.
Concept 39. 2: Skeletal systems transform muscle contraction into locomotion § Skeletal muscles are attached in antagonistic pairs, the actions of which are coordinated by the nervous system § The skeleton provides a rigid structure to which muscles attach § Skeletons function in support, protection, and movement © 2014 Pearson Education, Inc.
Figure 39. 10 Human forearm (internal skeleton) Extensor muscle Flexion Biceps Grasshopper tibia (external skeleton) Flexor muscle Triceps Extension Biceps Extensor muscle Flexor muscle Triceps Key © 2014 Pearson Education, Inc. Contracting muscle Relaxing muscle
Types of Skeletal Systems § The three main types of skeletons are § Hydrostatic skeletons (lack hard parts) § Exoskeletons (external hard parts) § Endoskeletons (internal hard parts) © 2014 Pearson Education, Inc.
Hydrostatic Skeletons § A hydrostatic skeleton consists of fluid held under pressure in a closed body compartment § This is the main type of skeleton in most cnidarians, flatworms, nematodes, and annelids § Annelids use their hydrostatic skeleton for peristalsis, a type of movement on land produced by rhythmic waves of muscle contractions © 2014 Pearson Education, Inc.
Figure 39. 11 Longitudinal muscle relaxed (extended) Circular muscle Longitudinal contracted muscle relaxed contracted Bristles Head end 1 Head end 2 3 © 2014 Pearson Education, Inc. Head end
Exoskeletons § An exoskeleton is a hard encasement deposited on the surface of an animal § Exoskeletons are found in most molluscs and arthropods § Arthropods have a jointed exoskeleton called a cuticle, which can be both strong and flexible § About 30– 50% of the arthropod cuticle consists of a polysaccharide called chitin § An arthropod must shed and regrow its exoskeleton when it grows © 2014 Pearson Education, Inc.
Endoskeletons § An endoskeleton consists of a hard internal skeleton, buried in soft tissue § Endoskeletons are found in organisms ranging from sponges to mammals § A mammalian skeleton has more than 200 bones § Some bones are fused; others are connected at joints by ligaments that allow freedom of movement © 2014 Pearson Education, Inc.
Figure 39. 12 Skull Shoulder girdle Clavicle Scapula Sternum Rib Humerus Vertebra Radius Ulna Pelvic girdle Carpals Phalanges Metacarpals Femur Patella Tibia Fibula Tarsals Metatarsals Phalanges © 2014 Pearson Education, Inc. Types of joints Ball-and-socket joint Hinge joint Pivot joint
Figure 39. 13 Ball-and-socket joint Head of humerus Scapula Hinge joint Humerus Ulna Pivot joint Ulna © 2014 Pearson Education, Inc. Radius
Size and Scale of Skeletons § An animal’s body structure must support its size § The weight of a body increases with the cube of its dimensions, while the strength of that body increases with the square of its dimensions © 2014 Pearson Education, Inc.
§ The skeletons of small and large animals have different proportions § In mammals and birds, the position of legs relative to the body is very important in determining how much weight the legs can bear © 2014 Pearson Education, Inc.
Types of Locomotion § Most animals are capable of locomotion, or active travel from place to place § In locomotion, energy is expended to overcome friction and gravity © 2014 Pearson Education, Inc.
Flying § Active flight requires that wings develop enough lift to overcome the downward force of gravity § Many flying animals have adaptations that reduce body mass § For example, birds have no teeth or urinary bladder, and their relatively large bones have air-filled regions © 2014 Pearson Education, Inc.
Locomotion on Land § Walking, running, or hopping on land requires an animal to support itself and move against gravity § Diverse adaptations for locomotion on land have evolved in vertebrates § For example, kangaroos have large, powerful muscles in their hind legs, suitable for hopping © 2014 Pearson Education, Inc.
Figure 39. 14 © 2014 Pearson Education, Inc.
Swimming § In water, friction is a bigger problem than gravity § Fast swimmers usually have a sleek, torpedo-like shape to minimize friction § Animals swim in diverse ways § Paddling with their legs as oars § Jet propulsion § Undulating their body and tail from side to side or up and down © 2014 Pearson Education, Inc.
Part 2: ANIMAL ETHOLOGY © 2014 Pearson Education, Inc.
Overview: The How and Why of Animal Activity § Fiddler crabs feed with their small claw and wave their large claw § Why do male fiddler crabs engage in claw-waving behavior? § Claw waving is used to repel other males and to attract females Video: Albatross Courtship Video: Boobies Courtship Video: Giraffe Courtship © 2014 Pearson Education, Inc.
Animal Ethology §Learning §Movement §Communication §Behavior © 2014 Pearson Education, Inc.
Animal learning: §Innate: § Fixed action pattern § Imprinting §Learned § Habituation § Associative learning § Classical conditioning § Operant conditioning §Observational learning © 2014 Pearson Education, Inc.
Fixed Action Patterns § A fixed action pattern is a sequence of unlearned, innate behaviors that is unchangeable § Once initiated, it is usually carried to completion § A fixed action pattern is triggered by an external cue known as a sign stimulus © 2014 Pearson Education, Inc.
Habituation §Loss of responsiveness to unimportant stimuli § Example: if someone taps you multiple times and you don’t want anything, you ignore it § Example: Ducklings normally run for cover whenever a birdlike objects fly overhead. They stop if this is done multiple times § **when studying animals some scientists wait to start recording this data– what is the purpose of this process? ** © 2014 Pearson Education, Inc.
Imprinting § Imprinting is the establishment of a long-lasting behavioral response to a particular individual § Imprinting can only take place during a specific time in development, called the sensitive period § A sensitive period is a limited developmental phase that is the only time when certain behaviors can be learned © 2014 Pearson Education, Inc.
§ An example of imprinting is young geese following their mother § Konrad Lorenz showed that when baby geese spent the first few hours of their life with him, they imprinted on him as their parent § The imprint stimulus in greylag geese is a nearby object that is moving away from the young geese Video: Ducklings © 2014 Pearson Education, Inc.
§ Conservation biologists have taken advantage of imprinting in programs to save the whooping crane from extinction § Young whooping cranes can imprint on humans in “crane suits” who then lead crane migrations using ultralight aircraft © 2014 Pearson Education, Inc.
Associative Learning § In associative learning, animals associate one feature of their environment with another § Classical conditioning § Dogs salivate when a bell rings § Operant conditioning: § a blue jay will avoid eating butterflies with specific colors after a bad experience with a distasteful monarch butterfly © 2014 Pearson Education, Inc.
Figure 39. 19 © 2014 Pearson Education, Inc.
§ Problem solving (insight learning) is the process of devising a strategy to overcome an obstacle § For example, chimpanzees can stack boxes in order to reach suspended food § For example, ravens obtained food suspended from a branch by a string by pulling up the string © 2014 Pearson Education, Inc.
§ Social learning (observational learning) is learning through the observation of others and forms the roots of culture § For example, young chimpanzees learn to crack palm nuts with stones by copying older chimpanzees © 2014 Pearson Education, Inc.
Spatial Learning and Cognitive Maps § Spatial learning is the establishment of a memory that reflects the spatial structure of the environment § Niko Tinbergen showed how digger wasps use landmarks to find nest entrances © 2014 Pearson Education, Inc.
Figure 39. 18 Experiment Nest Pinecone Results Nest © 2014 Pearson Education, Inc. No nest
Types of animal movement §Kinesis §Migration §Taxis © 2014 Pearson Education, Inc.
Migration § Environmental cues can trigger movement in a particular direction § Migration is a regular, long-distance change in location § Animals can orient themselves using § The position of the sun and their circadian clock, an internal 24 -hour activity rhythm or cycle § The position of the sun or stars § Earth’s magnetic field © 2014 Pearson Education, Inc.
Behavioral Rhythms § Some animal behavior is affected by the animal’s circadian rhythm, a daily cycle of rest and activity § Behaviors such as migration and reproduction are linked to changing seasons, or a circannual rhythm § Daylight and darkness are common seasonal cues § Some behaviors are linked to lunar cycles, which affect tidal movements © 2014 Pearson Education, Inc.
Animal Behavior © 2014 Pearson Education, Inc.
Foraging Behavior § Foraging is a behavior essential for survival and reproduction that includes recognizing, capturing, and eating food items § Natural selection refines behaviors that enhance the efficiency of feeding © 2014 Pearson Education, Inc.
§ In Drosophila melanogaster, variation in a gene dictates foraging behavior in the larvae § Larvae with one allele travel farther while foraging than larvae with the other allele § Larvae in high-density populations benefit from foraging farther food, while larvae in low-density populations benefit from short-distance foraging © 2014 Pearson Education, Inc.
Figure 39. 20 Mean path length (cm) 7 Low population density 6 High population density 5 4 3 2 1 0 R 1 © 2014 Pearson Education, Inc. R 2 R 3 K 1 D. melanogaster lineages K 2 K 3
Mating Behavior and Mate Choice § Mating behavior includes seeking or attracting mates, choosing among potential mates, competing for mates, and caring for offspring § Mating relationships define a number of distinct mating systems © 2014 Pearson Education, Inc.
Mating Systems and Sexual Dimorphism § The mating relationship between males and females varies greatly from species to species § In some species there are no strong pair-bonds § In monogamous relationships, one male mates with one female § Males and females with monogamous mating systems have similar external morphologies © 2014 Pearson Education, Inc.
Figure 39. 21 (a) Monogamous species (b) Polygynous species © 2014 Pearson Education, Inc. (c) Polyandrous species
Figure 39. 21 a (a) Monogamous species © 2014 Pearson Education, Inc.
Figure 39. 21 b (b) Polygynous species © 2014 Pearson Education, Inc.
Figure 39. 21 c (c) Polyandrous species © 2014 Pearson Education, Inc.
§ In polygamous relationships, an individual of one sex mates with several individuals of the other sex § Species with polygamous mating systems are usually sexually dimorphic: males and females have different external morphologies § Polygamous relationships can be either polygynous or polyandrous © 2014 Pearson Education, Inc.
§ In polygyny, one male mates with many females § The males are usually more showy and larger than the females © 2014 Pearson Education, Inc.
§ In polyandry, one female mates with many males § The females are often more showy than the males © 2014 Pearson Education, Inc.
Mating Systems and Parental Care § Needs of the young are an important factor constraining evolution of mating systems © 2014 Pearson Education, Inc.
§ Consider bird species where chicks need a continuous supply of food § A male maximizes his reproductive success by staying with his mate and caring for his chicks (monogamy) § Consider bird species where chicks are soon able to feed and care for themselves § A male maximizes his reproductive success by seeking additional mates (polygyny) © 2014 Pearson Education, Inc.
§ Certainty of paternity influences parental care and mating behavior § Females can be certain that eggs laid or young born contain her genes; however, paternal certainty depends on mating behavior § Paternal certainty is relatively low in species with internal fertilization because mating and birth are separated over time © 2014 Pearson Education, Inc.
§ Certainty of paternity is much higher when egg laying and mating occur together, as in external fertilization § In species with external fertilization, parental care is at least as likely to be by males as by females © 2014 Pearson Education, Inc.
Figure 39. 22 © 2014 Pearson Education, Inc.
Sexual Selection and Mate Choice § Sexual dimorphism results from sexual selection, a form of natural selection § In intersexual selection, members of one sex choose mates on the basis of certain traits § Intrasexual selection involves competition between members of the same sex for mates © 2014 Pearson Education, Inc.
§ Female choice is a type of intersexual competition § Females can drive sexual selection by choosing males with specific behaviors or features of anatomy § For example, female stalk-eyed flies choose males with relatively long eyestalks § Ornaments, such as long eyestalks, often correlate with health and vitality Video: Chimp Agonistic Video: Snakes Wrestling Video: Wolves Agonistic © 2014 Pearson Education, Inc.
Figure 39. 23 © 2014 Pearson Education, Inc.
§ Male competition for mates is a source of intrasexual selection that can reduce variation among males § Such competition may involve agonistic behavior, an often ritualized contest that determines which competitor gains access to a resource © 2014 Pearson Education, Inc.
Concept 39. 6: Inclusive fitness can account for the evolution of behavior, including altruism § The definition of fitness can be expanded beyond individual survival to help explain “selfless” behavior © 2014 Pearson Education, Inc.
Genetic Basis of Behavior § Differences at a single locus can sometimes have a large effect on behavior § For example, male prairie voles pair-bond with their mates, while male meadow voles do not § The level of a specific receptor for a neurotransmitter determines which behavioral pattern develops © 2014 Pearson Education, Inc.
Figure 39. 24 © 2014 Pearson Education, Inc.
Genetic Variation and the Evolution of Behavior § When behavioral variation within a species corresponds to environmental variation, it may be evidence of past evolution © 2014 Pearson Education, Inc.
Case Study: Variation in Prey Selection § The natural diet of western garter snakes varies by population § Coastal populations feed mostly on banana slugs, while inland populations rarely eat banana slugs § Studies have shown that the differences in diet are genetic § The two populations differ in their ability to detect and respond to specific odor molecules produced by the banana slugs © 2014 Pearson Education, Inc.
Figure 39. 25 © 2014 Pearson Education, Inc.
Altruism § Natural selection favors behavior that maximizes an individual’s survival and reproduction § These behaviors are often selfish § On occasion, some animals behave in ways that reduce their individual fitness but increase the fitness of others § This kind of behavior is called altruism, or selflessness © 2014 Pearson Education, Inc.
§ For example, under threat from a predator, an individual Belding’s ground squirrel will make an alarm call to warn others, even though calling increases the chances that the caller is killed § For example, in naked mole rat populations, nonreproductive individuals may sacrifice their lives protecting their reproductive queen and kings from predators © 2014 Pearson Education, Inc.
Figure 39. 26 © 2014 Pearson Education, Inc.
Inclusive Fitness § Altruism can be explained by inclusive fitness § Inclusive fitness is the total effect an individual has on proliferating its genes by producing offspring and helping close relatives produce offspring © 2014 Pearson Education, Inc.
Hamilton’s Rule and Kin Selection § William Hamilton proposed a quantitative measure for predicting when natural selection would favor altruistic acts among related individuals § Three key variables in an altruistic act § Benefit to the recipient (B) § Cost to the altruistic (C) § Coefficient of relatedness (the fraction of genes that, on average, are shared; r) © 2014 Pearson Education, Inc.
§ Natural selection favors altruism when r. B C § This inequality is called Hamilton’s rule § Hamilton’s rule is illustrated with the following example of a girl who risks her life to save her brother © 2014 Pearson Education, Inc.
§ Assume the average individual has two children. As a result of the sister’s action § The brother can now father two children, so B 2 § The sister has a 25% chance of dying and not being able to have two children, so C 0. 25 2 0. 5 § The brother and sister share half their genes on average, so r 0. 5 § If the sister saves her brother, r. B ( 1) C ( 0. 5) © 2014 Pearson Education, Inc.
Figure 39. 27 Parent A Parent B OR ½ (0. 5) probability Sibling 1 © 2014 Pearson Education, Inc. Sibling 2
§ Kin selection is the natural selection that favors this kind of altruistic behavior by enhancing reproductive success of relatives © 2014 Pearson Education, Inc.
Figure 39. UN 03 Imprinting Learning and problem solving Cognition Associative learning © 2014 Pearson Education, Inc. Spatial learning Social learning
Animal Signals and Communication § In behavioral ecology, a signal is a behavior that causes a change in another animal’s behavior § Communication is the transmission and reception of signals § Chemical - phermones § Visual- sight § Auditory- sound § Tactile - touch © 2014 Pearson Education, Inc.
Chemical: Pheromones § Many animals that communicate through odors emit chemical substances called pheromones § A female moth can attract a male moth several kilometers distant § A honeybee queen produces a pheromone that affects the development and behavior of female workers and male drones § When a minnow or catfish is injured, an alarm substance in the fish’s skin disperses in the water, causing nearby fish to seek safety © 2014 Pearson Education, Inc.
Fly courtship follows a 3 step stimulus response: using different types of communication 1. A male identifies a female of the same species and orients toward her § he smells a female’s chemicals in the air § he sees the female and orients his body toward hers 2. The male alerts the female to his presence § he taps the female with a foreleg 3. The male produces a courtship song to inform the female of his species § he extends and vibrates his wing **If all three steps are successful, the female will allow the male to copulate** © 2014 Pearson Education, Inc.
§ Honeybees show complex communication with symbolic language § A bee returning from the field performs a dance to communicate information about the distance and direction of a food source © 2014 Pearson Education, Inc.
Figure 39. 16 (b) Round dance (food near) (a) Worker bees (c) Waggle dance (food distant) 30 A 30 B Beehive C Location A © 2014 Pearson Education, Inc. Location B Location C
- Slides: 118