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PLANTS ARE PRODUCERS• PLANTS CAPTURE ENERGY FROM THE SUN.
– The sun’s heat & light provide the energy almost all organisms need to live.
– Light energy must be changed into chemical energy (the form of energy all organisms use to carry out the functions of life). Plants capture energy from the Sun & convert it to chemical energy (via photosynthesis).
• PLANTS ARE ADAPTED TO DIFFERENT ENVIRONMENTS
• PLANTS RESPOND TO THEIR ENVIRONMENT• PLANTS RESPOND TO SEASONAL CHANGES
PLANTS & SUN• PHOTOSYNTHESIS:
plants use sunlight to make chemical energy(in energy rich sugar molecule)
• Sunlight + 6CO2 +6H2OC6H12O6 + 6O2
• Most photosynthesis occurs in leaf, stem holds it up to sun, and roots anchor in soil and give H20.
• AUTOTROPH= self-feeder; another name for plants
• Algae, some bacteria & some protists also use photosynthesis
• Plants are mulitcellular though & can store more energy than the others
• Starch = energy rich molecule made of sugars plants store energy in.
• Cellular respiration = how cells break down sugars for energy release. (C6H12O6 + 6O2 6CO2 + 6H2O + energy)
• Some plants store starch in roots (carrots/beets) & others in stems (rhubarb)
PLANTS ADAPT TO DIFFERENT ENVIRONMENT
• Almost all land has some type of plants• GRASSES: deep roots, quickly makes seeds, found in
most environments (as longs as roots survive, grass grows back)
• TREES: not survive if leaves/stem die; need lots water; coniferous (needle-leaves stay green) do well in cold, deciduous(lose leaves in cold)need long growing season
• Some plants (desert & snowy mountain) must reproduce quickly while timing is good for them (seeds sprout, flowers grow, & new seeds made within just a few weeks)
PLANTS ADAPT TO ENVIRONMENTS
• Some plants adapt to protect: mustard gives off odor; poison ivy & oak make chemical & tobacco makes nicotine (poison) to keep insects from eating them.
• Venus fly trap has teeth on leaf edges to capture insects & makes digestive fluid to break insect down for important materials not found in local soil
Plants Respond to Environment
• Plants respond to stimuli (change in environment causing a response) to survive & grow.
• Gravity: roots drawn down & stems grow up, even if seedling is on its side.
• Touch: “tendrils” (found in peas, & climbing plants) are special stems that wrap around objects to grow upward to sun
• Light: stems grow towards it; plant releases auxin (plant hormone) at tip of stem. This moves away from light & stimulates cell growth, causing plant to bend towards the sun.
PLANTS RESPOND TO SEASONAL CHANGES
• Shorter time of daylight affects amount of sunlight available for photosynthesis. So plant goes into “dormancy”. Plant stops growing & needs less energy.
PLANTS RESPOND TO SEASONAL CHANGES
• In temperate climates, approach of winter causes leaves of deciduos trees to die & drop to ground.
• In some plants (like trees) they go into dormancy & grow in spring again; in others (like wild cornflowers) they die and only grow back in spring due to seeds left behind.
• Short-day plants (rice/ragweed) only flower in fall or winter; long-day plants (lettuce/spinach) flower only in late spring & summer.