1 / 22

Stimulus & Response

Stimulus & Response. Stimulus. A change in organism’s environment. Types of Stimuli. A stimulus can either be external or internal. Ex ternal stimuli- come from things found in the environment. Examples- temperature, predators, length of daylight, presence of water or food, etc.

anneh
Download Presentation

Stimulus & Response

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Stimulus & Response

  2. Stimulus Achange in organism’s environment

  3. Types of Stimuli • A stimulus can either be external or internal. • External stimuli- come from things found in the environment. Examples- temperature, predators, length of daylight, presence of water or food, etc. • Internal stimuli- come from things within an organism Examples- germs, dehydration, lack of energy, pain, lack of sleep

  4. Stimulus Is this stimulus external or internal?

  5. Response An organisms reaction to change.

  6. Response

  7. Homeostasis Homeo- same Stasis- state of balance The purpose of response to stimuli in organisms is to maintain homeostasis, a balance within it’s internal systems, or protection.

  8. Examples • Stimulus = Is this internal or external? • Response = • Stimulus = Is this internal or external? • Response = Lack of water Wilting (to conserve water) Bacteria or Virus Fever (to kill germs)

  9. Fight or Flight Response • An organisms biological response to extreme stress. • Can include- • Increased heart and breath rate • Shaking • Adrenaline rush- extreme strength • Freezing in place (cannot move)

  10. Examples of Fight or Flight

  11. Tropisms • Tropism = plant’s growth response toward or away from a stimulus

  12. Tropisms • Tropism = plant’s growth response toward or away from a stimulus • Positive tropism • Negative tropism

  13. Tropisms • Tropism = plant’s growth response toward or away from a stimulus • Positive tropism = plant grows toward a stimulus • Negative tropism

  14. Tropisms • Tropism = plant’s growth response toward or away from a stimulus • Positive tropism = plant grows toward a stimulus • Negative tropism = plant grows away from a stimulus

  15. Phototropism Plants grow toward a source of light Animation: http://botanical-online.com/animation8.htm

  16. Examples

  17. Hydrotropism Hydrotropism = a plant’s rootsgrow toward water Is this positive or negative?

  18. Gravitropism • A plant grows with or against gravity • Also called Geotropism Positive- A plant’s roots grow down, with the pull of gravity Negative- A plant’s stems or trunk grow up, against the pull of gravity. Animation: http://botanical-online.com/animation4.htm

  19. Regardless of the position a seed is planted in, the roots grow down with gravity and the stem up against gravity. Regardless of the slope of the land, the tree grows up against gravity.

  20. Thigmotropism A plant grows toward or away from pressure Positive turns toward pressure Negative turns away from pressure

  21. Working Together • Plant tropisms work together to maintain homeostasis within the plant + phototropism - geotropism + geotropism + hydrotropism

  22. Turgor Pressure This celery stalk has the least amount of turgor pressure because of water pressure in the cells This celery stalk has more turgor pressure than the 1st This celery stalk has the most turgor pressure of all because it has the greatest water pressure in the cells of the plant The pressure exerted by water inside the cell against the cell wall.

More Related