5C_Photosynthesis+Review

Watch the video "The Private Lives of Plants - Growing" and answer the following questions: o Why do young seedlings of climbers grow away from light? By heading for shade, they head for the nearest tree trunks. They need to find a host - a prop to climb. They also grow horizontally (roots into ground), till they reach the trunks. (food provided by parents allow it to travel about 6 feet; if doesn't find it then, will die of starvation. Once they reach the tree trunks, they start growing upwards, produce own leaves. The higher it is, the more leaves it has, the more energy it has, the bigger its leaves are. Direct relationship between height and surface area of leaves. 'Baby' leaves shrivel and die later.)

o What are the forces that cause the leaves to unfold during growth? (ferns) Hydraulic (water) pressure. A lot of water in the leaves. (Like water in a glove. Press one side, can pop out the fingers).

o Why are some of the leaves and leaf stalks “hairy”? To trap water. Roots are very small - not much water. Young leaves are soft and tender. Thinner cells, thinner wax layer, very fine xylem tube, tend to loose a lot of water, need 'hair' to trap water. Dense hairs on leaves to keep the pores open (rainwater)

o Name as many different types of leaf shape as possible. lobed leaves - larger surface area. needle shaped leaves. palmate ; five-fingered hand leaves (chestnut).

o Name a few strategies that plants use to gather light. In thick forests Plants can continually move its leaves to catch the moving shafts of light. Higher up, the leaves are placed in just the right positions - don't overlap that much (even in different trees). Any available space taken up. A mosaic. Crown shying. Produce chemicals that prevent them from overlapping that much. Only overlap when you plant them too close to each other. Bottom: a plant can wait for 10 or 20 years while waiting for an adult tree to move/die and for light to pass through, then will grow. Reflective surface: Is red underneath, is reflected back and bounce back into body of leaf. Surface very very dark green - a lot of chlorophyll. Spines- more surface area. maximum amount gathered. (Begonia) Have cells that act like lenses to focus the light the the chlorophyll. (Begonia) (Indoor plants are usually found in the shade. Undergrowth plants. Strive and succeed growing in the shade.)

o Why do roots have root hairs? What are their characteristics?

o How much water is loss through the stomata?

o How do trees “pump” water up its trunk to the leaves in the canopy layer?

o What are the properties of these “pipes”? What are they called?

o How do plants prevent the problem of having too much water accumulating on its large leaf surface especially in the tropics? If water covers the plant surface, it'll clog up the pore, interfere with transpiration. drain-like structures to let water drain down. Many have pointy tips at the end ensure that all the water is drained out. Have to be tough to stand the downpour.

o Why do proboscis monkeys have to spend so many hours eating? Why do they have a large belly? The digestive system of the monkeys cannot deal with the cellulose from leaves. It has bacteria to help deal with them/break them down. Like a huge fermentor inside; takes time. Same with cows (one of the by-products, apart from carbohydrates, is the gas methane).

o How do you tell the difference between a leaf that has been eaten by a caterpillar and that of a grasshopper? Caterpilla have to protect themselves form predators. A caterpillar starts by making a semicircular cut into the cut. Half way through, goes the other way. Then pulls it over (silk?).This is usually done at night, when there are no birds. Then they can eat it

o What are the damages that are inflicted on plants? What strategies do these plants employ to protect themselves? Use the examples featured in the show to explain their strategies e.g. Acacia, Nettle, pebble plant, passion flowers, bracken, mimosa, Venus fly trap, marsh pitcher Giraffes have very tough hides and very mobile tongues. So they can eat it during the day under the cover of Umbrella shaped. Outside, many thorns. In the middle, not so many thorns. Save energy (giraffes can't reach the Nettles: have flowers under their leaves. Their stings: a whole hair made of silicon, filled with poison. Breaks upon touch, releases the poison. The dead nettle: has found protection in mimicry (doesn't have stings) (Antidote: Dog's leg) The pebble plant - in the desert(?), looks like pebbles, even changes color to surrounding, most animals don't see it. Passion flowers: have yellow spots/buds that look like butterfly eggs - butterflies don't lay eggs on plants that already have eggs. Bracken: full of a cocktail of poisons that any animals that eat it will probably get cancer/go blind. Young: leaves contain cyanide. Older: much more complex poisons. A serious problem in Europe. A type of fern, survived since dinosaur age till now. When they dry up, they're a fire hazard. Mimosa: one touch makes it fold its leaves, another one makes it fold its leaves. (grasshopper: when it crawls onto the leaf, it closes. Then it goes down and tips it off. Venus fly trap: shapes the trap fro the end of its leaves. Touch a hair (inside_ and the trap is sprung. The insect struggles, making the trap close even more tightly. Digestive juices then fill it, insect is eaten. Not enough nutrients from soils. Marsh pitcher: leaves have been folded lengthways to make a vertical tube filled with water. (trumpets) Once the insect falls off the rim, into the water, where it decays? decomposes? and the juice is absorbed by the plant. (where one ant goes, so do the rest.) Frogs often wait just at the rim of the plant to catch any insects that fall in, though if they loose their footing, they'll eat eaten as well.

though the formula doesn't change, different plants have different methods/adaptations to get more/optimum light.