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Mating Systems, signaling, language, communication, sexual dimorphism, monogamy
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Day 16 October 30th Chapter 9Mating Systems
Dr. Amy B HollingsworthNatural Science Biology
Fall 2014
9.14 Monogamy versus polygamy: mating patterns can vary across human and animal cultures.
Mating Systems
Polygamy• When some individuals attract multiple
mates while other individuals attract none
Monogamy • Most individuals mate and remain with
just one other individual
Mating Systems
Polygamy subdivided into:
Polygyny • Individual males mate with multiple
females
Polyandry• Individual females mate with multiple
males
Mating Systems Are Not Easy to Define
Three issues complicate the task:
1. Differences between animals’mating behavior and bonding behavior
2. Mating system variation within the species3. Males and females vary in their mating
behavior
Pair bond—appears monogamous
Examination of Birds and Mammals Reveals One Sharp Split
Are humans monogamous or polygamous?
9.15 Sexual dimorphism is an indicator of population mating behavior.
Body Size Is an Important Clue to Behavior.
Level of competition among the individuals of each sex
Selection for larger and larger body size when competition is high
It’s almost impossible to distinguish males from females among most bird species.
Why does that mean they are monogamous?
Men are bigger than women.
What does that tell us about our evolutionary history of monogamy
versus polygamy?
9.16–9.17
Communication
and the design of
signals evolve.
Chemical Communication in Animals
Communication
An action or signal on the part of one organism that alters the behavior of another organism
What types of animal behavior require communication?
What types of communication do animals use?
Types of Animal Communication
Chemical Acoustical Visual
Complex Forms of Communication
Honeybee waggle dance
What is language?
How is language identified?
Vervet monkeys
American Sign Language taught to chimpanzees and gorillas
Human language
9.17 Honest signals reduce deception.
Conveying accurate information
Honest Signal
Cannot be faked
Given when both the individual making the signal and the individual responding to it have the same interests
Carries the most accurate information about an individual or situation
Deception evolves!
“Begging” allele
Evolutionary “arms race”• Unambiguous signals• Sophisticated patterns of deception
An organism’s phenotype includes its behaviors.