Middle School ScienceMiddle School Science

Mrs. FigotenMrs. Figoten

DO LEAVES ON TREES

IN ALL BIOMES

CHANGE COLOR?

Leaves change colorseasonally only indeciduous forests.

Warm summers & cold winters

50+ cm precipitation/yr

Trees shed leaves yearly

AUTUMNAUTUMN LEAFLEAF CHANGESCHANGES

Earth’s tilt changes in Northern Hemisphere

Less daylight,cooler temperatures

What signals leaves to change color in autumn?

What What causescauses leafleaf color?color?

3 pigments in each leaf- the amount in each leaf varies

ChlorophyllCaroteneCaroteneAnthocyaninAnthocyanin

AUTUMNAUTUMN LEAFLEAF CHANGESCHANGES

Leaf appears green

Present in leaf membrane

Needs sunlight in order to make food for tree through photosynthesis

Leaf appears yellowLeaf appears yellow

Remains in leaf membrane as Remains in leaf membrane as chlorophyll disappearschlorophyll disappears

Helps with photosynthesisHelps with photosynthesis

Birch & Hickory leavesBirch & Hickory leaves have lots of carotenehave lots of carotene

Leaf appears red/purpleLeaf appears red/purple

Present in cell sapPresent in cell sap

Reacts with sugar from photosynthesisReacts with sugar from photosynthesis

In some trees, sugar in leaves increasesIn some trees, sugar in leaves increasesin autumnin autumn

Red Maple, Red Oak & Sumac leaves have Red Maple, Red Oak & Sumac leaves have lots of anthocyaninlots of anthocyanin

WHAT DO PLANTS NEED WHAT DO PLANTS NEED FOR PHOTOSYNTHESIS?FOR PHOTOSYNTHESIS?

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DOES ANYTHING ELSE MAKEDOES ANYTHING ELSE MAKE ITS OWN FOOD USING ITS OWN FOOD USING

PHOTOSYNTHESIS?PHOTOSYNTHESIS?