WHAT DO YOU KNOW ABOUT PLANTS? Sketch this plant in your notebook and label the parts of the plant that you can identify.

WHAT DO YOU KNOW ABOUT PLANTS? PLANTS HAVE ORGANS TOO! What is the function of each of these parts of the plant?

WHAT DO YOU KNOW ABOUT PLANTS? PLANTS HAVE ORGANS TOO! traps energy from the sun to make “food” site of gas exchange (carbon dioxide and oxygen) anchors the plant to the ground absorbs water and nutrients (minerals) from the soil provides structure and support positions the leaves to collect sunlight contains the reproductive structures

WHAT DO YOU KNOW ABOUT PLANTS? PLANTS HAVE ORGAN SYSTEMS TOO! The Shoots System parts of the plant above ground stems, leaves, flowers The Roots System part of the plant below ground The Reproductive System Flowers/cones

Wolffia angusta Golden Barrel Cactus Fern Spanish Moss Hydnora africana

Golden Barrel Cactus Does this plant have all four plant structures? Where are the leaves? the stem? Why are the leaves and stem shaped the way they are?

Does this plant have all four plant structures? Fern

Do these plants have all four plant structures? Where are the roots? Spanish Moss Do they flower?

Does this plant have all four plant structures? Wolffia angusta: each speck is an individual plant! In what environment do you think these plants live?

Does this plant have all four plant structures? Hydnora africana

SO WHAT REALLY MAKES A PLANT A PLANT!?! T H E I R C E L L S ! ! ! cell wall nucleus plasma membrane cytoplasm ribosomes DNAlarge, central vacuole chloroplast

WHAT DO PLANTS NEED TO SURVIVE?

WHAT EXACTLY DO PLANTS NEED TO SURVIVE?

What nutrients do plants need? Nitrogen, phosphorus, potassium, calcium, magnesium, sulfur Where do they come from? The soil…they get dissolved in the water absorbed by the plant.

WHAT EXACTLY DO PLANTS NEED TO SURVIVE? SO HOW DO PLANTS GET ALL OF THESE THINGS?

NONVASCULAR PLANTS  The first plants to evolve were very simple, very small – they did not have roots or stems!  Cannot transport water, food, or nutrients so all cells must be able to absorb water directly and make what they need!  In what type of environment do you think they must have lived? Why?  Why do you think they had to stay small? WET!

SO HOW DO WE HAVE BIG, TALL, COMPLEX PLANTS THAT DO NOT LIVE IN WATER?!?! WHAT WAS THE GREATEST CHALLENGE TO PLANTS AS THEY BEGIN TO MOVE ONTO LAND?

VASCULAR PLANTS  Plants evolved a way to transport water and nutrients and therefore could grow much larger, with cells far away from the water source.  This transport system (the vascular system) is made up of specialized plant cells, called vascular tissue. Plant Cells Vascular Tissues Vascular System Vascular Plant

 Vascular tissues transport materials from one part of the plant to another and spans both the roots and shoots systems. Shoots System Roots System

 Vascular tissues transport materials from one part of the plant to another and spans both the roots and shoots systems.  Xylem –transports water and minerals upward from the roots to the shoots  Phloem –transports nutrients (food/sugars) from the leaves where food is made to the rest of the plant This vascular system allowed for the evolution of…. bigger, more complex plants that could live on land! top/leaves bottom/roots

HOW DOES WATER GET INTO THE PLANT? WHAT MAKES WATER TRAVEL UPWARD, AGAINST GRAVITY?

HOW DOES THE WATER GET INTO THE XYLEM?  Osmosis – movement of water from high concentration to low concentration. Water moves into the root cells because there is less water in the roots than in the soil. By osmosis through the root cells H2OH2O

PATH OF WATER ENTERING A ROOT

HOW DOES THE XYLEM WORK?  Once water has entered the xylem, it continues to “want” to move upward because of osmosis.  the tendency for water to rise within a thin narrow tube due to adhesion and cohesion! (like a straw!) But how can it move against gravity?!? What does adhesion and cohesion mean?!?

COHESION  Cohesion – water sticks to water because of hydrogen bonds  In plants, each water molecule pulls on the next water molecule and on and on until the water pulls up the xylem!

ADHESION  Adhesion – the attraction between unlike molecules  So together, cohesion and adhesion allow water to stick together and stick to the sides of the xylem and thus pull the water UP the xylem = capillary action!!!  In plants, this is water sticking to other substances, like the walls of the xylem

HOW DOES THE XYLEM WORK? Transpiration is the evaporation of water from the leaves of plants  Transpiration is like you sucking on a straw!  The water exits the leaves through openings, or pores, called stomata H2OH2O H2OH2O  Capillary action & osmosis are not enough to bring the water ALL THE WAY UP to the leaves.

STOMATA  stomata not only allow water vapor to evaporate from the leaves of plants What else could enter and exit through these very tiny openings?  Stomata also allow gases into and out of the plant What gas is entering the plant? What gas is exiting the plant? CO 2 O2O2

NOW WE KNOW HOW PLANTS TRANSPORT WATER UP, BUT WHAT HAPPENS WHEN IT REACHES THE TOP?!?

WATER LOSS  On average, plants use 90% of water that enters the through their roots  What doesn’t get used, is lost through transpiration – when the water evaporates from the leaves through the stomata  This helps cool the leaf, which is great, but it also means water is lost, especially when it is very hot or dry – conditions when the plant should be “saving” water!!!

TRANSPIRATION RATES  Vary from plant to plant.  Broad leaves= ___________ transpiration rates  Narrow leaves= __________ transpiration rates  Depends upon environmental factors  Temperature  Humidity  Air Movement.  In what type of environment would transpiration rates be highest? higher lower

TO PREVENT WATER LOSS, PLANTS HAVE HAD TO ADAPT! 1. Thin, narrow leaves 2. Reduced number of stomata Why? Decreased surface area Why? Fewer places from which water can escape 3. Guard cells What?!? Two specialized cells that surround each stoma and control how “open” or “closed” they are

TO PREVENT WATER LOSS, PLANTS HAVE HAD TO ADAPT! 4. Cuticle Why? The large, central vacuoles of each cell store extra water for dry times! 5. Water Storage What?!? Thick, waxy layer on the outside of plants that helps seal in water

Trace the pathway of water from the roots and shoots systems of a plant to the atmosphere.  Use the following terms:  Cohesion  Adhesion  Capillary Action  Transpiration  Evaporation  Include data from your lab activities and demos to support your explanations. * This should be well written, in complete sentences! ON THE LEFT OR RIGHT SIDE OF YOUR NOTEBOOK, COMPLETE THE FOLLOWING REFLECTION: