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!