Ecology: Sociobiology - University of Texas at Austin · Ecology: Sociobiology Behavior refers to...
Transcript of Ecology: Sociobiology - University of Texas at Austin · Ecology: Sociobiology Behavior refers to...
Ecology: SociobiologyEcology: Sociobiology
Behavior refers to coordinated responses that an animal makes
to stimuli
OutlineOutline
1. Key concepts
2. The study of animal behavior
3. The link between genetics and behavior
4. Social behaviors ultimately aid the reproductive fitness of individuals
5. Conclusions
Key Concepts:Key Concepts:
1. Behavior refers to coordinated responses
that an animal makes to stimuli
2. Forms of behavior have a genetic basis
3. Certain behaviors are instinctive and are
triggered by sign stimuli
4. Behavior has evolved by way of natural
selection
Key Concepts:Key Concepts:
5. Evolved modes of communication
underlie social behavior
6. Having a social group has costs and
benefits
The study of animal The study of animal behaviorbehavior
Behavior: patterns of movement, sounds, body postures, or any type of change exhibited by an animal
• Types of behavior:
� Simple: response to stimulus
� Complex: innate responses to learned behavior
• Animal behaviorists study mechanisms of behavior and evolutionary basis for them
The link between genetics The link between genetics and behaviorand behavior
Behaviors depend on neurophysiological
mechanisms so genes must be involved:
• Innate behaviors: programs which are part of the nervous system; performed correctly first time
• Learned behaviors: acquired by experience
Some animals can change their Some animals can change their behaviors based on experiencebehaviors based on experience
Learned behaviors and survival
Instinctive behavior: important for survival, but cannot be changed
Learned behavior: adaptation to changing conditions based on experience
Instinctive Instinctive behaviorsbehaviors
A male white-throated sparrow and a spectrogram of his song. A spectrogram is a visual record of the pitch or frequency of eachnote, measured in kilohertz. The sparrow repeats the same song over and over. His song is a response to the effect of environmental cues on a brain primed during development to respond to those cues.
Instinctive Instinctive behaviorsbehaviors
What's wrong with this picture? This young cuckoo is much larger than its foster parent, and is colored entirely differently. Yet when the cuckoo opens its mouth and begs, the foster parent feeds it. The parent is responding to the simple sign stimulus of a gaping mouth in its nest.
Learned behaviorsLearned behaviors
Learned behaviorsLearned behaviors
A young toad has neural wiring that causes it to flip its stickytongue at any dark object moving across its field of vision. But if it captures a yellow jacket that stings its tongue, it will learn to avoid attacking black-and-yellow-banded, yellow-jacket-size objects.
Very painful, away from porcupines!
Social behaviors ultimately aid the Social behaviors ultimately aid the reproductive fitness of individualsreproductive fitness of individuals
1. Communication via social behaviors
2. Competitive behaviors
3. Reproductive behaviors
4. Parenting behaviors and altruism
5. Group behaviors
6. Human behavior
Social behaviorsSocial behaviors
These wildebeests, live in largely unrelated herds. Still others, including termites and honeybees, live in huge groups of thousands of related individuals.
Social behaviorsSocial behaviors
Baboons and wolves both live cooperatively, sharing food and the care of the young. In both groups, there is a dominance hierarchy. Members of a baboon troop give up safe sleeping places, choice bits of food, and even receptive females to dominant baboons. Similarly, only one male and one female wolf typically produce pups.
Communication via social Communication via social behaviorsbehaviors
Social behaviors: help members of the same species communicate and interact
Advantages:� Reproduction
� Care of offspring
� Defense of a territory
� Obtaining food
� Defending against predators
Dances of HoneybeesDances of Honeybees
Cost of Living in Social GroupsCost of Living in Social Groups
� Competition for food
� Competition for mate
� Spread of contagious disease and parasites
Social behaviorsSocial behaviors
Walruses hang out in huge groups on the ice or on rocky islands. They have thick skin, with folds at every joint. The skin folds harbor blood-sucking lice, which spread easily from walrus to adjacent walrus.
Competitive behaviorsCompetitive behaviors
Used when two or more individuals want same scarce resource (food, water, mate) � Threat displays
� Submissive behavior
� Territorial behavior
Consequences: � Establishment of new populations
� Most “fit” have resources to reproduce
Competitive Competitive behaviorsbehaviors
Exposed canines are part of a male baboon's threat display. Often, when threatened in this manner, the rival backs down. If so, the signaler benefits, because he retains access to the female without putting up a fight. The signal receiver benefits, because he avoids a serious beating, infected wounds, and possibly death.
Competitive behaviorsCompetitive behaviors
Competitive behaviorsCompetitive behaviors
Competitive behaviorsCompetitive behaviors
Male-male competition for females: male bison, bighorn sheep, and elk competing for access to females. In such species, females will mate with the male that controls a particular area. The females choose the area, then the males fight for control of that territory.
Reproductive behaviorsReproductive behaviors
Sexual reproduction:
produces genetic variability among organisms of the same species
increases chances of adaptation and survival of individuals of a species
requires mating behaviors based on communication and cooperation
Reproductive behaviorsReproductive behaviors
Fixed pattern courtship rituals are species-specific and lead to mating
Male behaviors which attract female:� Mark and aggressively defend territory
� Display attractive body colors or patterns
� Emit noises or songs as mating calls
� Ritual dances
� Odors attractive to females
Reproductive behaviorsReproductive behaviors
Ritual wrestling by rattlesnakes
Male peacock
Parenting behaviors and Parenting behaviors and altruismaltruism
• Altruistic behaviors: benefit one individual at the cost of another
� Parenting behaviors allow young to survive and reproduce
• Parenting Activities:
� Build protective structure for young
� Provide food
� Defend nest
Altruistic behaviorsAltruistic behaviors
An altruistic individual behaves in a self-sacrificing way that helps others but decreases its own chance of reproductive success. Given that such individuals do not contribute their own genes to the next generation.
Group behaviorsGroup behaviors
Social groups (temporary or permanent) work for common good of a species
Individuals within the group� have more protection against predators
� warn each other of danger
� protect all young together
� obtain food together
� more efficient division of work by activity
Group behaviorsGroup behaviors
A school of goatfish. Prey animals may form such a group as a result of each individual attempting to place others between itself and any potential predators. In such a selfish herd, individuals try to hide behind others by moving into the center of the group.
Group behaviorsGroup behaviors
Musk oxen combining their defenses to form a "ring of horns" against predators. In the presence of a perceived threat (usually wolves), the adults form a circle around their young.
Human behaviorHuman behavior
• Study of human sociobiology has inherent limitations:
� cannot experimentally manipulate genes
� cannot vary environments of humans for scientific studies
In ConclusionIn Conclusion
1. Animal behavior originates with genes that
specify products required for the development
and operation of different systems
2. A behavior performed without having been
learned by actual experience is instinctive
3. Experiences can lead to variations or changes in
responses
4. Behavior with a genetic basis is subject to
evolution and natural selection
In ConclusionIn Conclusion
5. Costs and benefits of social life are reflected in
the individual’s reproductive success
6. Social groups have costs as well as benefits
7. Altruistic behavior limits chances of
reproduction by helping others of their social
groups
I love my baby Rhino!