An Evolutionary View of Behavior Starr/Taggart’s Biology: The Unity and Diversity of Life, 9e Chapter 47

Ethology vs. Behavioral Ecology: Ethology: the study of behavior Visible action Chemical signals Learning Behavioral ecology: the study of behavior and evolution, in other words how does behavior increase fitness

One can look at populations and learn many things! Naked mole rats! Fig. 47.22, p. 848

Genes and Behavior: Behavior is a combo of nature and nurture! Behavioral responses depend on: Neural patterns Patterns are based on genes There may be a selective pressure on those genes

Hormones and Behavior Recall that hormones are signaling molecules They can impact behavior Example of hormonal impact on behavior: “song system” in male birds Change in photoperiod affects pineal gland Pineal reduces melatonin secretion Gonads release testosterone Testosterone activates singing behavior

Sterotyped Behavior (innate) Characteristics: Instinctive Behavior will display on first encounter with stimulus based on nervous system pathways “Sign stimuli” or an external sensory stimulus will trigger a fixed action pattern It is developmentally fixed = sequence of acts that are unchangeable and are completed when started Fixed action patterns help in mating, predator evasion, energy conservation, food acquisition, and finding shelter

Sterotyped behavior (innate) Steps: 10:40 Sterotyped behavior (innate) Fixed action patterns are sequences of acts that are unchangeable and are completed when started Baby bird crying for food Moth folding its wings and dropping to ground at a bat’s ultrasonic cry

Learned Behavior In learned behavior animals modifies behavior based on experience Vervet monkey alarm calls improve over time The capacity to learn is wired into an animal’s nervous system Wiring determines what an animal can learn

Learned Behavior Examples Imprinting: exposure to key stimuli during a sensitive period Maturation: when a behavior onsets due to developmental progression flight

The Adaptive Value of Behavior Reproductive success refers to the survival and production of offspring (fitness) Adaptive behaviors promote the propagation of an individual’s genes Social behavior is based on communication signals and is cooperative Selfish behavior is when an individual acts to boost its own fitness Altruistic behavior is associated with decreasing individual’s success but boosting group’s success

Altruistic behavior example: Meercats

Cost of Living in Social Groups Competition for food Competition for mate Spread of contagious disease and parasites Risk of being killed or exploited

Communication Signals Communication signals are actions or cues that have a beneficial effect on the signaler and receiver during an exchange of information Pheromones are powerful! Composite signals can be chemical, acoustical, and visual

Dances of Honeybees Tactile displays LifeSci: 52120

Dominance Hierarchies Established by agonistic behavior which is a combo of both threatening and submissive displays that determine access to a resource Members of a group are ranked according to status Status can change over time

Fig. 47.13, p. 841

Fig. 47.19, p. 845

Territoriality: Territories are defended areas for feeding, mating, and rearing young Usually associated with males Rituals and dominance hierarchies reduce aggression

Courtship Behavior leading to copulation.

Fig. 47.11, p. 840

Parenting: Time and energy drain! Genes live on! LifeSci: 48745, 49017, 49176, 49361