1) Go outside and visit trees with leaves 2) Using evidence from your observations, identify the main parts of a tree above ground. 3) Your teacher will ask you for your answer and your evidence to back up your answer

1 ) Stems: - radial symmetry (many axes of symmetry) - long-lived - continuous growth 2) Leaves - bilateral symmetry (one axis of symmetry) - short-lived - pre-determined growth

1) Stems: - support structure for leaves - contain transport tissues for plant 2) Leaves - energy conversion light  sugar - absorb light and CO2 for photosynthesis

Roots - radial symmetry - long-lived - continuous growth - absorb water and nutrients from soil - provide support for the rest of the plant

 Complete Part 3 (p )  Show me when you get done with part 3 question 2  Completed Part 3 Due next class

Outer Bark: protection, continually renewed controls moisture, wards off insects Inner Bark: Phloem, transports sugars, dies to become more outer bark Cambium Layer: point of new cell growth, can produce more sapwood or phloem cells Responds to auxin hormones from buds Sapwood:Xylem, water transport cells, as they get old and compacted they become heartwood Heartwood: central supporting pillar, old xylem compacted and glued together by lignin

How is it determined? Count the rings.. 1 ring of wood = 1 year’s growth Found in Sapwood & Heartwood Heartwood rings more difficult to count – thinner Thick rings = good growth conditions Thin rings = bad growth conditions “Branches” & “trunks” both have rings

= Bark is removed in a strip around the entire circumference of the tree - severs the phloem from the roots to the leaves - no more sugar transport to roots - eventual death of tree - also provides access for insects

1) Length of day/night 2) Pigments found within the leaf 3) Weather conditions (temp & rainfall) Length of day/night = photo-period Photo-period is the key trigger for leaf change Intensity of color may vary with weather

1) Chlorophyll – reflects green light, absorbs red and blue wavelengths the best 2)Carotenoids – reflect yellow, orange and brown (corn, daffodils, carrots, bananas) 3)Anthocyanins – reflect deep red, purple and blue (cranberries, blueberries, apples) Chlorophyll masks Carotenoids throughout the year In Autumn – chlorophyll is lost and anthocyanins are made Green gives way to other colors

 Warm sunny days with cool nights produce brighter colors  Produces more anthocyanins  Harsh conditions early in the year reduce color: drought late-coming spring too hot in the fall

 Leaves are susceptible to freezing which damages the plant  Trees shed leaves to avoid this  Pine needles have a waxy coating – freeze resistant  Pine needles are less effective at photosynthesis