Bellwork: February 19 Copy the statement and question Underline key words

Science Fact of the Day: An ostrich's eye is bigger than its brain.

Transport System Essential Question: How does a plant use the transport system to maintain homeostasis?

Homeostasis refers to an organisms ability to maintain a stable internal condition Think-Pair-Share What are some examples of things your body regulates? **Regulate=maintain homeostasis***

Today we’re going to look at how plants maintain homeostasis.

Remember: Plant Parts/Systems Reproductive System = Flower (with male and female parts) Transport System = tissues in stem Nutrient System = Leaf + Root Structural Support System = Stem + Roots All of these parts and systems work together to help a plant maintain homeostasis.

What is the structural support system made of?

Roots Hold plant in position Absorb water and minerals from the soil Specialized cells to increase surface area for water intake

Wheat seed Root hairs Fragile parts of cells that grow from the main root They massively increase the surface area for absorption

Root hair cells (x150)

Stems: - are supporting structures that connect and carry water and nutrients between the roots and leaves

What is the transport system made of?

Vascular tissue: specialized tissue used to move water and nutrients throughout a plant.

Xylem: carries water upward from the roots to every part of the plant. Phloem: transports food (nutrients) produced by photosynthesis.

How are the parts of a leaf related to their function?

Leaves are organs that perform photosynthesis and contain one or more bundles of vascular tissue.

Cuticle: a thick waxy layer on the top of the leaf that protects the leaf against water loss and injury.

Structures of the Leaf Photosynthesis Conserves water Transports water and sugar to stem and roots

Stoma position

Leaf diagram – palisade layer CO 2 Most chlorophyll

Gas exchange Leaves are designed to allow carbon dioxide to get to the main chlorophyll layer at the top of the leaf They have small holes called stomata on the under surface Each hole is open & closed by 2 guard cells

Stomata: openings in the underside of the leaf that allow CO 2, O 2, and H 2 O to move into and out of the leaf. Guard cells: specialized cells in the epidermis that control the opening and closing of stomata.

Stoma is a small hole Its size is controlled by 2 guard cells closed open

Stoma function is for gas exchange in the leaf Carbon dioxide oxygen Guard cell Provided plant is photosynthesising

Why would a plant open and close its stomata?

Stomata open and close at different times of the day When it is light the plant needs CO 2 for photosynthesis so the stoma open At night (darkness) they close to conserve water

Gas exchange

Transpiration is the loss of water through leaves.

Osmotic pressure keeps a plant’s leaves and stems rigid. Wilting results from the lack of water—and therefore of the pressure in a plant’s cells.

Debrief: Explain how the plant would respond if… There was a drought? There was a flood? HOMEWORK: Plant Systems by Alyssa Dolny (youtube)

Mix-Freeze-Group I am the vascular tissue that transports nutrients through the plant. I am the structure around the stomata that allows gases to enter and exit the leaf. I am the process during which water is lost through the leaves. I am the vascular tissue that transports water throughout the plant. Phloem Xylem Guard CellTranspiration