Responses to Stimuli: Taxes Flashcards Preview

A2 Biology: Response to Stimuli > Responses to Stimuli: Taxes > Flashcards

Flashcards in Responses to Stimuli: Taxes Deck (8):
1

what is a taxis?

a taxis is a simple response whose direction is determined by the direction of the stimulus

2

how do motile organisms respond to environmental changes?

by moving its whole body either towards a favourable stimulus or away from an unfavourable stimulus

3

what are the 2 ways taxes are classified by?

1. according to whether the movement is towards/away from the stimulus
2. the nature of the stimulus

4

what is it called when the movement is towards the stimulus?

positive taxis

5

what is it called when the movement is away from the stimulus?

negative taxis

6

when single-celled algae move towards light (positive phototaxis), how does this increase their chances of survival?

as they are photosynthetic and require light to produce their food

7

when earthworms move away from light (negative phototaxis), how does this increase their chances of survival?

as it takes them into the soil where they are better to conserve water, find food and avoid predators

8

some species of bacteria will move towards a region where glucose is more highly concentrated (positive chemotaxis), how does this increase their chances of survival?

as they use glucose as a source of food