HOW DO PLANTS GROW SCIENCE CH 4 L

HOW DO PLANTS GROW? SCIENCE CH. 4 L. 4 NOTES (PG. 110 – 113)

VOCABULARY • TROPISM – WAYS THAT PLANTS CHANGE THEIR DIRECTION OF GROWTH IN RESPONSE TO THE ENVIRONMENT. • GROWTH HORMONE – A KIND OF CHEMICAL THAT AFFECTS PLANT GROWTH.

DNA • EVERY ORGANISM HAS DIFFERENT DNA • DNA DETERMINES HOW AN ORGANISM LOOKS • TELLS WHAT SHAPE AND SIZE IT WILL BE • PINE TREES ARE TYPICALLY CONE SHAPED • ENVIRONMENT HELPS DETERMINE SIZE AND GROWTH OF ORGANISMS

GROWTH • DETERMINED BY DNA AND ENVIRONMENT • PLANTS WILL GROW AT DIFFERENT RATES DUE TO DIFFERENT DNA • ENVIRONMENT CAN CAUSE SLOW OR FAST GROWTH • TOO COLD, LACK OF NUTRIENTS, LACK OF WATER WILL CAUSE LESS HEALTHY PLANTS

GROWTH CELLS MAY GROW FASTER ON ONE SIDE OF PLANT THAN THE OTHER. • STEM – ONE SIDE WITH FASTER GROWTH WILL MAKE THE STEM BEND

GROWTH • PART OF PLANT MAY HAVE MORE GROWTH HORMONE THAN OTHER. • PLANTS MAKE THEIR OWN GROWTH HORMONES. • AMOUNT OF WATER IN CELLS MIGHT CHANGE • VACUOLES HOLD WATER IN CELLS • MORE WATER = BIGGER CELLS = BIGGER PLANTS

TROPISMS!!! • GROW IN DIFFERENT DIRECTIONS TO BEST MEET NEEDS • LEAVES TOWARD SUN, ROOTS TOWARD WATER, ETC. • HAPPENS WHEN THE ENVIRONMENT CHANGES THE AMOUNT THAT CELLS GROW ON DIFFERENT SIDES OF THE PLANT.

GRAVITROPISM • GROWTH OF A PLANT OR PLANT PART IN RELATION TO GRAVITY. • STEMS USUALLY GROW UP AGAINST GRAVITY • ROOTS USUALLY GROW DOWN WITH GRAVITY

PHOTOTROPISM • PLANT’S REACTION TO A SOURCE OF LIGHT. • STEM MAY GROW TOWARD LIGHT • LEAVES MAY TURN TOWARD LIGHT

THIGMOTROPISM • PLANT’S GROWTH IN RESPONSE TO TOUCHING AN OBJECT. • HAPPENS IN STEMS AND ROOTS • VERY COMMON WITH VINE PLANTS • ROOTS MAY BEND AWAY FROM ROCKS OR HARD SOIL