Biology 1A    Dec 3, 1998
Lecture 24 - Biomes & Hormones

Page Contents :

• Reading Assignment
• Overview of Reading
• Reading Outline
• Vocabulary
• Study Questions
• Related Websites

Stern: Chapter 11, 25

Overview of Reading:

The Nitrogen Cycle (p.453-454).
Biomes (p. 460-467).
Plant Hormones (p.182-188).

A. tundra
B. taiga
C. temperate deciduous forest
D. grassland
E. desert
F. mountain forests
G. tropical rain forest

A. auxins
B. gibberellins
C. abscisic acid
D. ethylene

 
   abscisic acid     epiphyte             permafrost
   agar              ethylene             taiga
   auxin             gibberellin          temperate deciduous forest
   coleoptile        grassland            tropical rain forest
   denitrification   mountain forests     tundra
   desert            nitrogen-fixation

• Where are auxins produced by the plant? How are they transported?
• What effect do auxins have on shoot growth?
• Can auxins inhibit root growth? Can they promote root growth? How can auxin be responsible for both?
• Your book says that auxins promote growth rather than control it; explain the difference.
• What uses do auxin sprays have for fruit growers? for control of weeds?
• In what organism(s) were gibberellins first discovered?
• What effect does gibberellin have on shoot growth? on root growth? Which group of plants are most sensitive to gibberellins?
• How are gibberellins used in grape production? in celery production? in brewing?
• What kind of biomolecule is cytokinin?
• What effect do cytokinins have on plant cells? on animal cells?
• In what plants and tissues were cytokinins discovered? In which tissues are they most commonly produced?
• Why is ABA called a "growth-inhibitting hormone"? How is such a hormone useful?
• In what tissues or structures does ABA usually function?
• How does ABA make it easier to ship plants?
• Which plant hormone is a gas?
• What effect does ethylene have on flowers, leaves, and fruits? How is ethylene useful to fruit growers?

• From where do plants get most of their nitrogen? In what form?
• If there is so much nitrogen in the air, then why don't plants make use of it?
• How does atmospheric nitrogen enter the nitrogen cycle? What organisms are responsible?
• What are some ways in which nitrogen is returned to the atmosphere?
• How is decay important to the nitrogen cycle?

• What is a biome?
• How much of the earth's surface is tundra? Where is tundra found in North America?
• Describe the climate of the tundra.
• What is the permafrost? Where is it found? What is its effect on tundra vegetation?
• What is taiga? What are some other names for the taiga? Where is taiga found in North America?
• Describe the climate and vegetation of the taiga.
• Describe the climate and vegetation of a temperate deciduous forest. Where can such forests be found in North America?
• How has European immigration affected the deciduous forests of North America?
• When do most flowers of the deciduous forest bloom? Why?
• Describe the climate and vegetation of a grassland. Where are they found in North America?
• Describe the climate and vegetation of a desert. Where are deserts found in North America?
• What adaptations do desert plants have for surviving there?
• What percent of earth's forest are tropical rain forests? Describe the climate of these forests.
• What are epiphytes, and how do they survive in tropical rain forests?

• UCMP - Biomes