Biology Chapter: Taxis, Kinesis, and Tropism

Questions and Answers

What is taxis?

A directional response to a stimulus.

What is kinesis?

A response in which the organism doesn't move towards or away from a stimulus but moves randomly.

What is one similarity and two differences between taxis and tropism?

Similarity: Directional response to a stimulus; Differences: Taxis is when a whole organism moves, while tropism is a growth response. Taxis occurs in animals, and tropism occurs in plants.

How does the distribution of IAA cause the root to bend?

IAA concentration is high at the bottom of the root, inhibiting elongation of cells, while the IAA concentration is low at the top of the root, leading to elongation of cells. Signup and view all the answers

Why was it important that the light was dim and even during the worm experiments?

Dim light mimics the worms' normal environment, prevents heat from affecting them, and ensures they do not show phototaxis. Signup and view all the answers

What is one possible explanation for the worms' behavior on the glass surfaces in the absence of food?

Worms are hungry and seeking food, or they move toward the temperature they were cultured in as they associate it with food. Signup and view all the answers

What are two common factors between taxis and kinesis?

Both are motions that organisms use to respond to a stimulus and are usually found in the behavior of animals and insects. Signup and view all the answers

What are the two types of kinesis?

Orthokinesis and klinokinesis. Signup and view all the answers

What is orthokinesis?

How fast the organism moves, which is dependent on the intensity of the stimulus. Signup and view all the answers

What is klinokinesis?

Involves the frequency of turning, which is proportional to the intensity of the stimulus. Signup and view all the answers

What is the difference between taxis and kinesis?

Taxis is directional and active, while kinesis is random. Signup and view all the answers

What is the mechanism in kinesis?

Rapid movements increase as the stimulus becomes more unpleasant, and random movements occur to bring the organism to favorable conditions. Signup and view all the answers

Give an alternative explanation for the flatworms' behavior observed by the student.

Could be random movement due to a small sample size or influenced by a chemical attractant in the mucus. Signup and view all the answers

How could the student modify her observations to determine whether the flatworms' behavior is a kinesis?

Record the number of turns (rate of movement). Signup and view all the answers

What are the three types of behavior patterns that invertebrates use including for escaping danger?

Taxis, kinesis, and reflex escape response. Signup and view all the answers

What is a reflex action?

A rapid and automatic response to a stimulus. Signup and view all the answers

What are the three main stimuli that plants need to respond to?

Light, gravity, water (Photo, Geo, Hydro). Signup and view all the answers

What is the importance of organisms responding to stimuli?

Organisms need to respond to stimuli to survive. Signup and view all the answers

What is tropism?

A growth movement in response to an external environmental stimulus. Signup and view all the answers

Study Notes

Taxis and Kinesis

Taxis is a directional movement towards or away from a stimulus.
Kinesis involves random movements that are not directed towards or away from a stimulus.
Both taxis and kinesis are behavioral responses used by organisms to react to stimuli, commonly observed in animals and insects.
Taxis can lead to a concentrated movement in response to stimuli, while kinesis results in varying movement patterns without a specific direction.

Differentiating Taxis and Tropism

Both taxis and tropism involve a response to stimuli; however, taxis refers to movement by the entire organism, whereas tropism is a growth response.
Taxis is primarily observed in animals, while tropism is seen in plants.

Tropism and IAA

Indole-3-acetic acid (IAA) concentration influences root bending; higher concentrations at the root's bottom inhibit cell elongation, while lower concentrations at the top promote it.
Uneven growth rates from IAA distribution result in the bending of the root toward greater growth.

Experimental Considerations on Worm Behavior

Dim light is essential as worms typically live in dark environments and to avoid heat damage from intense light.
Even light prevents phototaxis, allowing for clear observation of the worms’ natural behaviors.
Worms in the experiment likely moved towards familiar temperatures associated with food, illustrating their foraging behavior.

Types of Kinesis

Orthokinesis refers to changes in the speed of movement based on stimulus intensity.
Klinokinesis involves changes in the frequency of turns relative to the intensity of the stimulus.

Reflex Actions

Reflex action is a quick, automatic response to stimuli, vital for immediate reactions, especially to danger.

Plant Stimuli Responses

Plants respond primarily to three stimuli: light (phototropism), gravity (geotropism), and water (hydrotropism).
These responses are critical for survival and adaptation to the environment.

Importance of Stimuli Responses

Organisms must respond to stimuli for survival, facilitating movement towards favorable conditions or away from threats.

Summary of Behavior Patterns in Invertebrates

Invertebrates utilize taxis, kinesis, and reflex escape responses to navigate their environment and respond to danger effectively.

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Description

Explore the concepts of taxis, kinesis, and tropism in this quiz. Understand how organisms respond to stimuli through movement and growth mechanisms. Test your knowledge on the influence of indole-3-acetic acid on plant behavior.