Animal Behavior

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UIC BioS 101 Nyberg

BEHAVIOR

The actions of an organism may be called behavior. Actions are traditionally responses that occur shortly after a stimulus.

Speaker Notes:

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UIC BioS 101 Nyberg

Reading Assignment

The assigned reading is Chapter 51.
Section 51.3 on hormonal & neural control may be skipped.

Speaker Notes:

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UIC BioS 101 Nyberg

Efforts to Explain Behaviors

Proximate – involve the mechanisms that underlay the action responding to a stimulus
Ultimate – why or how the behavior functions, why or how it improves fitness
The chapter should be read skeptically. Ask if the appropriate evidence is actually provided.

Speaker Notes:

Courtship rituals are often elaborate. We already looked at some types of feeding in fishes.

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UIC BioS 101 Nyberg

Types of Behavior

Two axes (Fig 51.2)
Learned versus Innate (not modified by experience)
Stereotyped versus conditional (flexible)
Are these axes really independent? It seems impossible to be in upper right or lower left, i.e. modified thru learning AND highly stereotyped.

Speaker Notes:

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Fixed Action Patterns

FAPs have little variation in performance sequence and timing.
Different in different species.
Sequence of actions is invariant once initiated (compressed time).
Often associated with prey capture.

Speaker Notes:

Predator’s attack on a prey often follows a fixed action pattern.

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Nature vs Nurture

Both genes and an adequate environment are necessary for individual development.

Both genetic variation and variation in environmental conditions effect the probability that specific behaviors will be manifest.

Speaker Notes:

Though identical twins have the same DNA, the expression of that genetic information can differ. This is an area of active research.

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Twin Studies

Identical twins have the same genotype.
Children in the same family share many environmental conditions as well as having genetic similarity.
Identical twins adopted into different families have the same genotype, but, presumably, grew up in different environments.

Speaker Notes:

Most twins are the consequence of two separate fertilizations. Identical twins are fairly rare and the number adopted into different families is low.

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Conditional Strategies

When behavior changes according to the environment in which an individual finds itself, we say the behavior is ‘conditional’.
The word ‘strategy’ is used in connection with alternative behaviors because biologists believe that behaviors are the product of adaptive evolution.

Speaker Notes:

The ‘environment’ an individual is responding to is often another individual of the same species.

Bee-eaters

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Why do the bee-eaters that don’t have to go far gather less food?

Speaker Notes:

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Many of the behaviors studied are associated with sex

Among the strange and unusual ‘behaviors’ is the capacity of some fish to change sex.
Figure 51.6 describes a situation in a reef fish where there is only one male in a group. If the male is removed, one of the larger females switches sex, i.e., becomes male.

Speaker Notes:

Can you think of an advantage for one of the small fish to become male? Look at Fig. 51.19.

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Game Theory can be used to Study Behavioral Strategies

Game theory provides ways to calculate the benefits of various strategies of playing games.
The rules of the biological ‘games’ are set by evolution and involve increasing the fitness of the players.

Speaker Notes:

Dr. Joel Brown in our Department is a leader in applying game theory to biology.

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Prisoner’s Dilemma Game Example

http://william-king.www.drexel.edu/top/eco/game/game.html

Speaker Notes:

Al and Bob are burglars that have been apprehended by the police. Their choice is to confess or not. The Numbers are the years Al, Bob will serve in jail.

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Learning

Classical conditioning (Pavlov) implies learning.
Imprinting (best known from birds) is a situation where young are programmed to identify with adults during a specific, limited phase of their life.
- Can only be discovered by ‘messing’ with species, i.e. disrupting the normal course of events.

Speaker Notes:

One of the behaviors that has not responded to selection is tendency of flies to turn right versus left.

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Can animals think?

I assert it is impossible to define ‘thinking’ in a way that I would have difficulty finding an animal that would fulfill the criteria, if the majority of human individuals fulfill the criteria.
For people with pets, it is obvious that animals ‘think’, if you call thinking being able to respond in an appropriate way to new situations.

Speaker Notes:

People like to think they are special and they are but only to a greater degree rather than manifesting completely new properties.

Tool making crows

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UIC BioS 101 Nyberg

Speaker Notes:

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Stories about adaptive value

Behaviors can be rationalized in terms of evolution.
The stories in your book seem to make sense, but what evidence is provided that excludes other plausible alternatives?
‘Why did they do that?’ doesn’t always have to make sense. Animals, like people, do ‘stupid’ things.

Speaker Notes:

Things work but that doesn’t mean there are no other things that would work equally well or even better.

Communication

What does it take to fool a redwing?

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Speaker Notes:

Honeybee description of food source

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Speaker Notes:

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Deception

Your goal as an individual is NOT to be deceived, but …
You may gain advantage by deceiving other individuals, but …
Taxes is a good example of a situation where many people lose real advantages by trying to gain individual advantage, to ‘beat the system’.

Speaker Notes:

People often accept part of their wage ‘under-the-counter’ to avoid paying income and social security taxes, but these same individuals qualify for much lower benefits later on.

Mimicry exploits deception

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Speaker Notes:

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Migration

The capacity of animals to navigate often exceeds the capacity of human individuals.
Most people depend on social organizations to find their way around, i.e. they buy a ticket to get to a place.
Species of animals show an impressive ability to navigate, especially to find home.

Speaker Notes:

Birds navigate over very long distances. Whooping cranes, an endangered species, were taught a new migration route using an ultralight airplane.

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Classification of interactions between individuals based on outcomes

Effect on Recipient

Effect on Initiator

Positive

Negative

Altruistic

-,+

Cooperative

+,+

Spiteful

-, -

Selfish

+, -

Speaker Notes:

We expect that individuals that initiate an action to gain from that action, so the left column is where most events are expercted.

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Kin Selection

Behavior that seems altruistic can be classified as selfish, if the cost to the initiator is less than the benefit to the initiator’s relatives.
The classical example is alarm calls. Birds that see a hawk often give a call that alerts other animals to the presence of the predator.

Speaker Notes:

Benefits are weighted by the degree of relationship.

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Calculating Coefficients of Relatedness

The symbol for the coefficient of relatedness of a pair of individuals is r
The value of 0 means the individuals are not related. The value of 1 represents genetic self identity
Full Siblings have an r value of 0.5
First cousins have an r value of 0.125

Speaker Notes:

The coefficient of relatedness estimates the likelihood two individuals carry genes identical-by-descent (IBD).

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Social Insects

Many species in the insect group Hymenoptera have complex social organizations.
Some colonies have only a single fertile individual known as the queen. Most ‘individuals’ are workers. Workers are haploid. The few males that are present are diploid.

Speaker Notes:

Ants, bees and termites are social insects, but not all species are social.

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UIC BioS 101 Nyberg

Vocabulary

Courtship
Learned
Innate
Fixed action pattern
Game theory
Deception

Altruism
Selfish
Kin selection
Coefficient of relatedness
Conditional strategy

Speaker Notes: