CHAPTER 51ANIMAL

BEHAVIORDanica MagañaPeriod 2, 2011

OVERVIEW All of our time spent on Earth,

humans have been curious about animal behavior.

Animal behavior is not only essential to the life of the animal but to those who hunt it.

Modern scientists study how behavior develops, evolves, and contributes to reproduction and survival.

51.1

Behavior traits are an important part of an animal’s phenotype.

Questions about behavior are put into two categories.

Proximate questions are “how?” questions that is concerned with the environmental, genetic, physiological, and anatomical stimuli that triggers a response.

Behavior can stem from muscular activity (catching prey) and no muscular activities (releasing hormones).

Everything an animal learns, does, and how it carries out an action is behavior.

51.1

1. What is the mechanistic basis of the behavior, including chemical, anatomical, and physiological mechanisms?

2. How does development of the animal influence the behavior?

3. What’s the evolutionary history of the behavior?

4. How does the behavior contribute to the survival and reproduction of the animal?

Four questions are used to fully understand animal behavior.

In the 1900’s, the study of animal behavior (ethology) came about.

51.2 Behavioral traits stem from complex

interactions between genetic and environmental factors. All behaviors are affected by both.

Behavior is a variable that depends on environmental experience. Thus, most of the individuals in the environment have identical behavior.

Strong genetic influence makes a behavior fixed and innate. Environmental differences do not alter innate behavior.

51.2 Kinesis is a change in activity due to a stimulus

response. Taxis is an automatic movement toward or

away from a stimulus. Migration is a regular movement of animals

over relatively long distances. This behavior is genetically programmed.

Signals is the social interaction between animals through specialized behaviors.

Animal communication consists of transmission, reception, and response.

A lot of communication is under strong genetic control. Environment makes contributions too.

51.2

Animals communicate using energy efficient visual, auditory, chemical, tactile, and electrical signals.

Pheromones are excreted by animals for both reproductive and nonreproductive behavior. They are very effective at low concentrations.

51.3

The environment affects and modifies many behaviors.

The most powerful way that can influence behavior is through learning by specific influences.

Those learned behaviors can be very simple or complex.

Habitation is the loss of response towards unimportant stimuli or stimuli that does not provide appropriate feedback.

51.3

Animals modify their behavior when to help it work with the spatial structure (nest sites, hazards, food, mates, etc) in their environment.

The capacity to know this enhances the survival of the animal.

The stability of an environment gives an animal different kinds of information for spatial learning.

To successfully learn animals use cognitive maps and codes for spatial arrangements.

51.4 Natural selection can result in different

behavioral traits thanks to evolution. Behavioral differences between related

species are common. Significant differences can be found

within animal species. Behavioral variation within a species

correlates to the variety in the environment. This can be used as evidence of past evolution.

51.4 The best way to find evidence of

evolution is by carrying out experiments on organisms with short life spans.

51.5

Genetic components evolve through natural selection favoring traits that enhance survival and reproduction.

Behavior can affect the fitness through influences on foraging and mate choice.

Foraging includes eating and mechanisms used to recognize, search for, and capture food.

51.5 Natural selection favors behavior that

minimizes the cost of foraging and maximizes the benefits.

Foraging is studied by applying cost-benefit analysis to study the proximate and ultimate causes of diverse strategies.

Optimal foraging theory says that the proportion of small to large prey captured will vary with prey density.

51.5

Smaller organisms will be selected when larger prey are far away.

Learning also improves the foraging efficiency.

Predation is the biggest risk a forager takes.

51.5

Mating behavior, which includes seeking and attracting mates, choosing potential mates, and competing for mates is called sexual selection.

Sexual selection goes hand in hand with mating behavior.

Mating relationships vary species to species.

Mating can be promiscuous. It can also be monogamous or polygamous.

51.5

Polygamous relationships are divided into 2 categories where it is a polygyny (one male, many females) or a polyandry (one females, many males)

The needs of the offspring constrain the evolution of mating systems.

Parental investment refers to the time and resources spent on raising the offspring.

Species can maximize reproductive success by seeking other mates.

51.5 Paternity can influence mating systems

and paternal care. If a male is unsure if a offspring is his,

he will invest less time. Male parental care occurs in 7% of fish

while it occurs in 69% of families with external fertilization.

51.5

Sexual dimorphism within a species results from sexual selection.

It is a form of natural selection where differences in reproductive success is a consequence of mating success.

Sexual selection is a form of intersexual selection where one sex chooses mates on the basis of particular characteristics of the other sex.

Mate preferences by females play a vital role in the evolution of male behavior and anatomy.

51.5

A female chooses a healthy male in order to get healthy offspring.

Males in turn compete with each other by agonistic behaviors to see who deserves the female.

More than one mating behavior can result is successful reproductions.

Intrasexual selection has led to the evolution of alternative male mating behavior and morphology.

51.5

The game theory suggests alternative strategies in situations where the outcome depends on each individual’s behavior in comparison to others.

Modeling showed that the relative success of different males vary with the abundance of other types of males.

THEMES OF BIOLOGY The most prominent theme featured in

this chapter is evolution. Evolution has everything to do with animal and human behaviors. It has changed the way people mate, who they mate with, and how they react to the environment. Another theme that is prominent is that an organism interacts with its environment. This is important because without interaction in the environment the animal would die or not mate. I’m sure many other themes are covered but these stand out to me.