Answer:
Step-by-step explanation:
Sure! Here are four points comparing reflex action and tropism:
1. Definition and Nature:
- Reflex Action: Reflex action is an involuntary and rapid response to a specific stimulus, usually involving the nervous system. It is a type of automatic response that occurs without conscious thought or decision-making.
- Tropism: Tropism is a growth or movement response exhibited by plants in response to external stimuli. It is a directional growth or movement towards or away from a stimulus, such as light or gravity.
2. Types of Organisms:
- Reflex Action: Reflex actions are typically observed in animals, including humans. They are mediated by the nervous system and involve sensory receptors, neurons, and effectors.
- Tropism: Tropisms are primarily observed in plants, although some simple organisms like fungi and bacteria may also exhibit tropic responses. Plants show various tropic responses, such as phototropism (response to light), geotropism/gravitropism (response to gravity), and thigmotropism (response to touch).
3. Stimulus and Response:
- Reflex Action: Reflex actions are triggered by specific stimuli, such as pain, heat, or pressure. The response is immediate and aims to protect the organism or maintain homeostasis. Examples include pulling away from a hot object or blinking in response to a bright light.
- Tropism: Tropic responses in plants are triggered by external stimuli, such as light, gravity, or touch. The response is gradual and directional, leading to growth or movement towards or away from the stimulus. Examples include plant stems bending towards a light source (positive phototropism) or roots growing downward due to gravity (positive geotropism).
4. Mechanism:
- Reflex Action: Reflex actions involve a complex neural pathway. When a sensory receptor detects a stimulus, it sends a signal to the spinal cord or brain, which then sends an immediate motor response signal to the effectors (muscles or glands) to produce the reflexive action.
- Tropism: Tropisms in plants are typically controlled by hormones and growth regulators. The stimuli are detected by specialized cells or structures in the plant, and the hormones direct the growth or movement towards or away from the stimulus. The response is often mediated by differential growth rates on different sides of the plant part, resulting in bending or curvature.
It's important to note that while reflex actions are quick and involve animals' nervous systems, tropisms are slower and primarily observed in plants as growth responses.