Lecture Notes: Organism Response to Stimuli

Introduction

• Organisms respond to stimuli for survival and adaptation.
• Stimulus: A change or signal in the environment which organisms recognize and react to.
• Response: The reaction to a stimulus.

Animal Responses

Eagle

• Stimulus: Spots fish in the lake.
• Response: Dives and catches fish with sharp talons.

Rabbit

• Stimulus: Senses a predator.
• Response: Runs to escape.

Gazelle

• Stimulus: Change in wind direction with scent of predator.
• Response: Alters course to avoid detection.

Birds

• Stimulus: Seasonal changes.
• Response: Migrate to warmer regions during winter.

Earthworm

• Stimulus: Presence of light.
• Response: Moves away to stay in dark soil.

Plant Responses

Phototropism

• Example: Sunflower plants turn towards the sun for photosynthesis.

Geotropism

• Example: Roots grow downwards, stems grow upwards.

Venus Fly Trap

• Stimulus: Insect lands on leaves.
• Response: Closes leaves to capture prey.

Microorganism Responses

Amoeba and Paramecia

• Stimulus: Harmful substances or food sources.
• Response: Move away from harmful substances, towards food sources.

Conclusion

• All organisms, including simple ones, can respond to stimuli.
• This ability is crucial for interacting with the environment, adapting to changes, and ensuring survival.

Note: Remember to subscribe for more content.