BIOL 1902 Lecture Notes - Xanthophyll, Thermostat, Stoma

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goldeel903

20 Jul 2012

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First stage triggered by change in photoperiod. Keeping needles creates new problem solar radiation: solution: xanthophyll pigments. Skunk cabbage turns up its heat (living thermostat) -> blooms quicker. Dessication is new problem (drying out: calm, sunny days are the worst. Conifers retain their leaves so size and shape is very important: avoid by having leaf surface area being small. Close stomata: how to retain water: thick cuticles (thicker on coniferous trees, retain leaves so size and shape is very important. Hairy underside of leaves: picks up air flow and retains moisture inside leaf (traps moisture, example is bog plant. Ferns: reduces leaf surface area by rolling them up. Deciduous trees have large leaves with large surface area: drops their leaves. Male trees turn red, female turns yellow: leaves produce anthocyanins, red -> aposematic coloration. Losing leaves prevents the heavy weight of snow. Northern trees shed snow: balsam fir are spire shape (sharp pointy trees, black spruce are spindly.

Related Questions

What is the function of the phloem? Select one: a. Phloem carries nitrogenous wastes to the roots where the waste leaves the plant. b. Phloem carries water and minerals to the rest of the plant from the roots. c. Phloem carries water from the leaves to the rest of the plant. d.

Phloem transports sugar down from the leaves to the rest of the plant. How do the cells of the xylem compare to the cells of the phloem? Select one: a. The xylem cells have thin cell walls, whereas the phloem cells have thick cell walls. b. The xylem cells are large, whereas the phloem cells are small. c. The xylem cells have chloroplasts, whereas the phloem cells do not have chloroplasts. d.

The xylem cells are square, whereas the phloem cells are round. From which part of the stem tissue is wood made? Select one: a. spongy mesophyll b. the cuticle c. old layers of xylem and phloem d. central parenchyma Flat leaves lose water to the environment more readily than pine needles do.

Which statement describes a structural characteristic of flat leaves that accounts for this difference? Select one: a. Flat leaves have a thicker coating of waterproof wax. b. Flat leaves have more surface area. c. Flat leaves have a thicker epidermis. d. The stomata of flat leaves are sunken into the leaf.

can all three questions be answered please

1. is it possible for natural selection to occur buta population to not evolve. Briefly describe a situation that couldallow that to happen.

2. Each year, all the ginkgo trees in an area drop their leavesat nearly the same time, a phenomenon called "The Night of theGinkgo". Give a plausible (not necessarily correct!), goodscientific hypothesis for this observation.

3. Many terrestrial mammals weigh much less than a pound, yetthe smallest fully marine mammal is the sea otter, which weighsover 30 lbs. as an adult. How might the surface area: volume ratiocontribute to the large size of marine mammals?

a. Animals with high SA:V ratios retain heat moreefficiently.

b. Animals with low SA:V ratio retain heat moreefficiently.

c. Animals with high SA:V ratios generate more heat via highermetabolisms.

d. Animals with low SA:V ratio are able to take more prey.