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BEHAVIOR

NATURE OF BEHAVIOR

Stimuli and Behavior

• An organism’s environment is always changing . These changes may involve one or more external factors, including heat, light, carbon dioxide, oxygen, moisture, and the activites of other organisms. Environmental changes also may involve internal factors , such as thirst and hunger.

• Any change in the external or internal environment is called a stimulus.

In a living organism, metabolic processes work best when homoestasis, or a stable internal environment, is maintained.

Living things maintain homeostasis by physiological or behavioral responses to stimuli.

Examples:

When a hungry dog smells food, it salivates

stimulus response

A person sweats when hot ???

• If this response does not cool the body, the person may remove outer clothing .

-Sweating is a physiological response.

- Removing outer clothing is behavior

BEHAVIOR: series of activities performed by an organism in response to stimuli.

Each species has its own pattern of behavior and it aids in the survival of the individual and the species.

PERCEIVING AND RESPOND TO STIMULI

LIGHT: The honey bee can see ultraviolet light but human cannot. And human’ white and bee’s white are different

Using a special ultraviolet-transmitting lens, Eisner and his coworkers at Cornell have demonstrated that many insect-pollinated flowers appear to the honeybee quite different from the way they appear to us. The sharp contrasts between flowers that appear similar to us partly explains the efficiency with which honeybees secure nectar from only one species of flower at a time even when other species are also in bloom.

PERCEIVING AND RESPOND TO STIMULI

SOUND: A bat uses echolocation by bouncing high –pitched sound of the objects.The bat is able to detect the echoes and determine whether an object is an obstacle or moving prey.

PERCEIVING AND RESPOND TO STIMULI

SMELL: Different organisms involves the senses of smell and chemicals.

Sex pheromones are sent by organisms who want to mate. When members of the same species, but of the opposite sex, pick up the sex pheromone signal they get excited and head towards the source. They can find this source, because the concentration of pheromone naturally increases closer to the sender. If this sender meets certain other criteria (tail length, color of the wings, size of the antlers, etc.) mating occurs. Pheromones are more important for insects than for mammals. While a grasshopper is controlled to a very large extent by the chemicals, a female lion inspects potential mates more critically. In the latter case pheromones are only luring chemicals.

If the water snails gets injured, proteins from his tissue serve as alarm pheromones to warn other members of his species

The spreading of pheromones is more difficult in the case of water creatures like fish because of currents and low diffusion rates

The first pheromones were discovered during research on the moth Bombyx Mori

A female mosquito uses exhaled CO2 to locate her victims

Sex pheromone of the butterfly Agrotis segetum

COORDINATING BEHAVIOR

The behavior of an organism depends on its form and Structure. The cheetah’s body structure permits it to run swiftly to catch prey. The robin escapes predators by flying away.

Behavior is affected by all body systems. The nervous system, endocrine system, muscles, and skeleton influence an organism’s response. The more complex an organism’s nervous system and structure are, the more complex its behavior is.

COORDINATING BEHAVIOR

THE NERVOUS SYSTEMS:

HYDRA

FLATWORM

Comparative brain sizes

COORDINATING BEHAVIOR

HEREDITY:

CYCLES OF BEHAVIORField mice are active at night and quiet during the day. They are generally nocturnal animals with superb hearing and vision (hence the large eyes and ears), because of this they are a vital source of food for other larger nocturnal hunters such as owls,

Morning glory flowers open during the day and close at night

CYCLES OF BEHAVIOR

Hawks hunt by day and owls by night.

Investigations into biological rhythms were conducted with hamsters. The circadian clock in the hamster brain signals a change in coat color according to season by releasing the melatonin hormone.This demonstrated that the cycle involved a physiological process.

Jet lag is a combination of symptoms experienced after flying in an airplane, especially on long trips. Fatigue, irritability, dehydration, and a broken sleep pattern are common symptoms of jet lag.