define tropism. write the short note on all types of tropism
Answers
Answered by
6
A tropism (from Greek τρόπος, tropos, "a turning") is a biological phenomenon, indicating growth or turning movement of a biological organism, usually a plant, in response to an environmental stimulus.
Types:
Phototropism
Many photosynthetic animals produce their food from sunlight. Therefore, sunlight has evolved as a stimulus for many organisms. Many of these organisms move towards the light. This positive phototropism causes organisms to move toward the light.
Heliotropism
A similar phenomena occurs in land plants. Terrestrial plants are restricted in their movements, due to their roots. Instead, plants orient their leaves toward the sun, to collect the most sunlight. This tropism is similar to phototropism, but the position of organism cannot change. Instead, the plant turns its leave by reducing or increasing turgor pressure, or water pressure, in individual cells.
Chemotropism
A widely spread tropism in the animal kingdom is chemotropism, or the tendency to turn or move towards or away from a specific chemical substance. Some single-celled organisms use different chemotropisms for different purposes. For example, one chemical might signal a mate, while another signals a dangerous or unpleasant area. These simple organisms will simply move towards or away from stimuli in the direction that has been most evolutionarily rewarding to their ancestors. In higher organisms, certain chemicals still attract animals, though they may not always move towards it. In other words, while they have the tropism, they do not always exhibit taxis. For instance, sharks have a positive chemotropism for blood, or they tend to move towards blood.
Thermotropism: A tropism that causes organisms to move towards a specific temperature.
Thigmotropism: Often, roots may turn when they touch a hard surface, like rock. The stimulus of touch drives this tropism.
Magnetotropism: Many animals may use the magnetic fields as a source of direction, and be drawn to certain poles.
Types:
Phototropism
Many photosynthetic animals produce their food from sunlight. Therefore, sunlight has evolved as a stimulus for many organisms. Many of these organisms move towards the light. This positive phototropism causes organisms to move toward the light.
Heliotropism
A similar phenomena occurs in land plants. Terrestrial plants are restricted in their movements, due to their roots. Instead, plants orient their leaves toward the sun, to collect the most sunlight. This tropism is similar to phototropism, but the position of organism cannot change. Instead, the plant turns its leave by reducing or increasing turgor pressure, or water pressure, in individual cells.
Chemotropism
A widely spread tropism in the animal kingdom is chemotropism, or the tendency to turn or move towards or away from a specific chemical substance. Some single-celled organisms use different chemotropisms for different purposes. For example, one chemical might signal a mate, while another signals a dangerous or unpleasant area. These simple organisms will simply move towards or away from stimuli in the direction that has been most evolutionarily rewarding to their ancestors. In higher organisms, certain chemicals still attract animals, though they may not always move towards it. In other words, while they have the tropism, they do not always exhibit taxis. For instance, sharks have a positive chemotropism for blood, or they tend to move towards blood.
Thermotropism: A tropism that causes organisms to move towards a specific temperature.
Thigmotropism: Often, roots may turn when they touch a hard surface, like rock. The stimulus of touch drives this tropism.
Magnetotropism: Many animals may use the magnetic fields as a source of direction, and be drawn to certain poles.
hg0126:
mark as brainliest
mark her as brain less hahaha
Answered by
3
A tropism is the innate ability of an organism to turn or move in response to a stimulus. As opposed to a learned ability, innate reactions are genetically programmed. Organisms with a tropism will naturally turn toward a stimulus. A stimulus can be any signal from the environment, and individual tropisms are often named after the stimulus that causes the movement. In a positive tropism the animal will move toward the stimulus. In a negative tropism, the animal will move away from the tropism. Certain stimuli become genetically engrained because they are always beneficial or always detrimental to an organism.
Similar questions