Timing and Coordination of Behaviors/Responses

Plants Respond to Changes in Light Phototropism Photoperiodism

Phototropism Plants grow towards sunlight Auxin is released on the shady side and moves down the tip- pushing the plant towards the sun Increases photosynthesis

Photoperiodism Plants only flower during certain seasons They recognize the length of the night using phytochromes

Animals Also Response to Environmental Cues and Signals Circadian rhythms Sleep/wake cycles Seasonal hibernation Seasonal migration Reproductive cycles

Circadian Rhythms Internal clocks found in most living things Can be affected or reset by environmental cues In humans- eyes sense the amount of light, triggers melatonin release, which affects sleep cycles

Sleep Wake Cycle

Mornings are Stressful…

Hibernation State of low metabolic rate to conserve energy Usually entered when food supplies will be unavailable, i.e. winter in tundra, summer in desert

Reproductive Cycles Some animals only reproduce during certain seasons I.e. in the estrus cycle many animals go into “heat” in the spring Controled by light exposure/melatonin

Mating Signals Use signals to attract mates during receptive periods Chemical signals like pheromones Mating dances/behaviors Text messages

Animals React to Information in their Environment 2 main types of behavioral responses: Innate Learned

Innate Behaviors Inherited responses like instincts I.e. you fear heights, you swim when placed in water, you move from hot things, you like sugar etc.

Other Examples of Innate Behavior Also fixed action patterns- some fish will attack anything with a red belly Imprinting – ability to learn during a critical period. Like bird song, or ducks who learn who their mother is

Learned Behaviors Occurs through interaction with the environment I.e. by seeing something, trial-and-error learning, associative learning etc.

Cooperativity Populations often interact in ways that ensure the survival of both Resource/niche partitioning Mutualistic relationships Pollinators/plants

Resource Partitioning Populations adapt to use different resources and avoid competition

Mutualism Species live together and both benefit

Pollination Bees/birds get food source, plants reproduce. Everyone wins!

All of These Mechanisms Have Arisen Through Natural Selection Mechanisms help organisms survive by increasing access to resources or decreasing risk of death Mechanisms help organism reproduce at appropriate times or find mates more easily