chapter 37 Flashcards

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1
Q

What is an autotroph?

A

make their own food, usually through photosynthesis

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2
Q

what is a heterotroph?

A

absorb energy or consume nutrients from another source

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3
Q

Do plants “eat” minerals they obtain from the soil?

A

No, they absorb minerals to use IN photosynthesis

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4
Q

What is photosynthesis?

A

the process that converts sunlight, CO2, and water into food for the organism

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5
Q

Do all autotrophs photosynthesize?

A

No, some are chemoautotrophs (use inorganic compounds in environment)

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6
Q

What is chlorophyll?

A

photosynthethic material found in chloroplast, helps trap light energy

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7
Q

What light does photosynthesis use?

A

everything but green

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8
Q

Where does water enter in plants?

A

roots

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9
Q

how does the plant get CO2?

A

through their stomata

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10
Q

when does photosynthesis occur?

A

daytime! when the sun is out

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11
Q

what process occurs in plants at night?

A

respiration, have to conserve starch until they can do photosynthesis again

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12
Q

where do plants obtain most of their water and minerals?

A

upper part of the soil

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13
Q

how does soil benefit from living organisms?

A

living organisms aerates the soil and provides nutrients in their poo

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14
Q

what are the basic physical properties of soil?

A

texture and composition

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15
Q

what are the 3 different soil types?

A

largest=sand, medium=slit, smallest=clay

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16
Q

describe sand

A

better drainage but hard to retain water

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17
Q

describe clay

A

retains water but no aeration

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18
Q

why is air important?

A

animals, plants, and bacteria need to respire

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19
Q

how do rock particles get into soil?

A

mechanical weathering- water freezing in crevices of rock
chemical weathering- weak acid dissolves rock
both- organisms penetrate and grow in rock

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20
Q

what are soil horizons?

A

soil stratified into layers

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21
Q

what is topsoil?

A

consists of mineral particles, living organisms, and humus

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22
Q

what is loam?

A

the most fertile soil type, equal amounts of sand, clay, and slit

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23
Q

why is topsoil the most important for plant growth?

A

roots dont penetrate farther than topsoil and humus makes the topsoil fertile

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24
Q

what is soil type?

A

refers to the size ratio of the particles in a sample. depends on the parent rock type, climate (affects weathering), and present organisms

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25
Q

what is humus?

A

formed by decomposes, it is very rich and fertile soil. it improves soil structure and traps water

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26
Q

what is the b horizon? (subsoil)

A

contains much less organic matter than the A horizon and is less weathered

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27
Q

what is the c horizon? (parent rock)

A

composed of mainly partially broken-down rock. some of the rock served as “parent” material for minerals that later helped form the upper horizons

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28
Q

what caused the american dust bowl of the 1930s?

A

combination of drought and inappropriate farming

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29
Q

what are aquifers?

A

they are underground water reserves and are the primary source of irrigation water

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30
Q

what is land subsidence?

A

a gradual settling or sudden sinking of earth’s surface

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31
Q

what is salinization?

A

the addition of salts to the soil which makes it an unsuitable environment for plants

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32
Q

what is a solution to irrigation?

A

to use drip irrigation- the slow release of water to soil and plants from perforated plastic tubing placed directly at the root zone. this technique uses less water and reduces salinization

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33
Q

how do soils become depleted or nutrients?

A

irrigation leaches nutrients and crop harvesting takes them away

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34
Q

what is fertilization?

A

the addition of mineral nutrients to the oil

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35
Q

what chemical elements are fertilizers enriched with?

A

nitrogen, phosphorus, and potassium (NPK ratio)

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36
Q

what are the pros and cons of inorganic fertilizers?

A

pros: more and faster crop growth
cons: manufacture requires fossil fuels, eutrophication occurs

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37
Q

what is eutrophication?

A

excess nutrients go into bodies of water

38
Q

what are the pros and cons of organic fertilizers?

A

pros: slow release of nutrients, improves soil texture, increase air spaces
cons: slow plant growth, needs to be manually spread out

39
Q

how does pH affect the soil?

A

affects cation exhange and chemical form of minerals

40
Q

what is the solution to adjusting soil pH?

A

there’s isnt one, its tricky to change soil pH so it’s best to plant crops best suited for that pH

41
Q

what is contour tilling?

A

crops plants in circles, it helps slow water runoff and topsoil erosion

42
Q

what is no-till agriculture?

A

narrow rows are plowed for seeds and fertilizer so the field is seeded with minimal disturbance to the soil

43
Q

what is phytoremediation?

A

uses plants to remove contaminates from polluted soil types

44
Q

What are some limitations of phytomediation?

A

contaminants could still get into water, affects herbivores

45
Q

what are the 6 macronutrients?

A

carbon, oxygen, nitrogen, phosphorus, sulfur, hydrogen

46
Q

What are the 8 micronutrients?

A

zinc chlorine iron manganese boron copper nickel and molybednum

47
Q

what are micronutrients used for?

A

for coenzymes

48
Q

whats phosphorus used for?

A

for nucleic acids

49
Q

whats sulfur used for?

A

makes proteins

50
Q

whats magnesium used for?

A

chlorophyll

51
Q

whats iron used for?

A

making different compounds

52
Q

a deficiency in a ______ nutrient will affect older leaves

A

mobile

53
Q

a deficient of a less mobile nutrient will affect _____ leaves more

A

younger

54
Q

what is the most common deficiency?

A

nitrogen deficiencies

55
Q

what does a iron deficiency look like?

A

younger leaves yellowing

56
Q

what does a nitrogen deficiency look like?

A

older leaves yellowing

57
Q

what does a deficiency of magnesium look like?

A

yellowing of the leaves; chlorosis

58
Q

what are smart plants?

A

plants that inform the grower of a nutrient deficiency before damage has occurred

59
Q

what do living plant roots provide for soil?

A

secretions from roots support microbes

60
Q

what do dead plant roots provide for soil?

A

nutrients and energy for microorganisms

61
Q

what are detritivores?

A

they recycle organic matter

62
Q

what is a rhizosphere?

A

the layer of soil closely surrounding the plants roots

63
Q

what is rhizobacteria?

A

free-living bacteria living in the rhizosphere

64
Q

what are endophytes

A

non-pathogenic bacteria that live between the cells of host plant tissues

65
Q

what do rhizobacteria and endophytes do for the plant?

A

stimulates plant growth, protects roots from disease, absorbing toxins and increasing nutrient availability

66
Q

why cant plants use atmospheric nitrogen?

A

the triple bond is too strong for the plant to break

67
Q

what forms of introgen can plants absorb?

A

nitrate or ammonia

68
Q

what is the nitrogen cycle?

A

describes the transformation of N2 and N2 compounds in nature

69
Q

what is nitrogen fixation?

A

reduction of N2 gas by a stepwise addition of 3 pairs of hydrogen atoms

70
Q

what is required for nitrogen fixation?

A

ATP, strong reducing agents, and nitrogenase

71
Q

what is nitrogenase used for in nitrogen fixation?

A

to catalyze the reaction

72
Q

How many ammonias are produced in nitrogen fixation?

A

2

73
Q

How much ATP is needed for nitrogen fixation?

A

16

74
Q

what are diazatrophs?

A

nitrogen-fixing bacteria

75
Q

What is the symbiotic bacteria in legume plants? (pea plants)

A

rhizobium

76
Q

what is the symbiotic bacteria in non-legume plants>

A

frankia

77
Q

what is crop rotation?

A

a non-legume is alternated with a legume to restore the concentration of fixed nitrogen in the soil

78
Q

what is mycorrhizae?

A

mutualistic association of fungi and roots

79
Q

what is the benefit for mycorrhizae fungi?

A

fungi gets carbs from host plant

80
Q

what is the benefit for host plants in mycorrhizae?

A

increased surface area for water uptake

growth secretions that promote branching

81
Q

what are the two types of mycorrhizae?

A

ectomycorrhizae and arbuscular (endo) mycorrhizae

82
Q

what is ectomycorrhizae?

A

they form a sheath OUTSIDE rootlets and penetrate root cells

83
Q

what is arbuscular mycorrhizae?

A

hyphae extend into the root but not the plasma membrane, occur in 85% of plants

84
Q

what are 3 adaptations that plants in nutritionally poor environments use other organisms to obtain N2 and nutrients in non-mutualistic ways?

A

epiphytes, parasitic, carnivorous

85
Q

what are epiphytes?

A

plants that grow on top of other plants (vanilla)

86
Q

what are parasitic plants?

A

absorb nutrients from hosts (mistletoe)

87
Q

what are carnivorous plants?

A

capture small animals/insects

88
Q

what are lobster pots?

A

can get in but not out

89
Q

what are bladder traps?

A

exclusive to bladderworts, the prey is sucked in and a trap door closes behind them

90
Q

what is the problem with nitrogenase?

A

it is very sensitive to oxygen and will deactivate. luckily most nitrogen-fixing bacteria are anaerobes