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bio 20 > ecology + ecosystems > Flashcards

ecology + ecosystems Flashcards

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Biology 101 flashcards
1
Q

does earth exchange matter and energy with its surroundings?

A

matter is not exchanged, but energy is

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2
Q

dynamic equilibrium

A

a state where constant changes in a system maintain a balance such that the entire system remains undisturbed

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3
Q

biosphere

A

narrow zone around earth that harbours life

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4
Q

why must energy be constantly provided to the biosphere?

A

energy lost as heat and through metabolic processes is no longer available for use in the system, meaning it must constantly be replenished

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5
Q

ecosystem

A

all the groups of organisms living in an area plus the non-living environment with which they interact

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6
Q

population

A

group of individuals of the same species occupying the same area at a given time

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7
Q

community

A

group of populations living and interacting with each other in an area (all the organisms within an ecosystem)

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8
Q

species

A

group of organisms that can interbreed and produce fertile offspring

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9
Q

biodiversity

A

the number of species within an ecosystem

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10
Q

biome

A

large, geographically defined region with similar climate, vegetation and animal life. determined by temperature and precipitation patterns

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11
Q

habitat

A

the geographic location and properties that is home to a particular species

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12
Q

ecology

A

the study of interactions between organisms and their biotic and abiotic environment

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13
Q

food chain

A

a sequence linking organisms that feed on each other, beginning with the food source and continuing sequentially with each consumer

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14
Q

producers (autotrophs)

A

organisms that produce their own food

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15
Q

consumers (heterotrophs)

A

organisms that eat producers or other consumers to survive

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16
Q

herbivores

A

animals that eat only plants

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17
Q

carnivores

A

animals that eat only other animals

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18
Q

omnivores

A

animals that eat both plants and other animals

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19
Q

scavengers

A

animals that feed on recently killed/dead plant or animal material

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20
Q

detritivores

A

organisms that ingest dead organic matter of fallen leaves and dead animals

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21
Q

saprotrophs

A

organisms that secrete digestive enzymes onto organic matter, allowing them to absorb nutrients in a digested form

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22
Q

how are saprotrophs important?

A

as digestion occurs externally, inorganic nutrients (eg. nitrogen) are cycled back into the soil, where they are used by autotrophs to grow

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23
Q

decomposers

A

organisms that break down detritus to obtain nutrients for their own use, but also release nutrients to soil and water

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24
Q

detritus

A

plant and animal waste, including dead remains

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25
Q

food web

A

represents the feeding relationships among all the organisms in an ecosystem

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26
Q

trophic level

A

category of living things defined by how it gains its energy

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27
Q

3 types of trophic levels

A

producers, consumers, decomposers

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28
Q

first trophic level

A

producer

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29
Q

second trophic level

A

primary consumer

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30
Q

what happens to the amount of energy available as you move up the food chain?

A

it decreases. this is because every time energy is transferred by components in a food chain, the amount of energy available to the next trophic level becomes reduced

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31
Q

10% rule

A

only 10% of the energy becomes available to the next trophic level

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32
Q

thermodynamics

A

the study of energy transformations

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33
Q

first law of thermodynamics

A

conservation of energy - energy cannot be created or destroyed, but it can be transferred from one form to another

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34
Q

second law of thermodynamics

A

entropy - some energy is transferred into an unusable form (thermal energy) when it is transferred. this energy is lost from the system

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35
Q

ecological pyramid

A

a representation of energy flow in food chains and webs

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36
Q

biomass

A

the total dry mass of all the living material in an ecosystem

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37
Q

what 2 consequences does the loss of energy with trophic levels create for an ecosystem?

A
  1. less biomass at higher trophic levels because productivity decreases
  2. lower biomass at higher trophic levels, along with large body mass of top consumers, results in lower population densities
38
Q

name the 3 ecological pyramids

A
  • pyramid of numbers
  • pyramid of biomass
  • pyramid of energy
39
Q

pyramid of numbers

A

outlines the number of organisms at each trophic level, based on #/unit area

40
Q

pyramid of biomass

A

outlines the total biomass at each trophic level, constructed by weighing the dry mass of tissue in all organisms measured. measured in biomass per unit area per unit time (g/m2/yr)

41
Q

pyramid of energy

A

outlines the amount of energy available at each trophic level, given in calories/joules. measured in energy per unit area per unit time

42
Q

are each of the pyramids always in a pyramid shape?

A

pyramids of energy always taken on a pyramid shape, whereas the others may vary - although this shape is most common

43
Q

chemosynthesis

A

the process of non-photosynthetic organisms converting inorganic chemicals to organic compounds without solar energy

44
Q

chemoautotrophs

A

perform chemosynthesis to make nutrients using only water, carbon dioxide and an energy source

45
Q

where is the energy used by chemoautotrophs found?

A

hydrothermal vents near the edges of earth’s crustal plates emit energy in the form of heat and inorganic molecules (eg. hydrogen sulfide, ammonia, ferrous ions, sulfur)

46
Q

environmental vegetarianism

A

the belief that production of meat and animal products is unsustainable due to inefficient energy consumption

47
Q

what 2 processes are involved in the cycling of matter?

A
  1. digestion (complex organic molecules are broken down in the body)
  2. decay (decomposers and detritivores break down organic matter in waste)
48
Q

name the 5 biogeochemical cycles

A

hydrological (water), carbon, oxygen, nitrogen, phosphorus

49
Q

list the steps of the water cycle

A

precipitation, collection (& percolation), evaporation, condensation

50
Q

percolation

A

the downward movement of water through soil due to gravity

51
Q

water table

A

region below the ground saturated with water

52
Q

leaching

A

the loss of dissolved organic matter and nutrients from the soil through percolation of water

53
Q

how do plants help counteract leaching?

A

they have deep, branching roots which return materials to the surface

54
Q

acid rain

A

precipitation of acidified water caused by emissions of sulfur dioxide and nitrous oxides

55
Q

carbon flux

A

the flow of carbon between carbon pools (net difference between removal and addition)

56
Q

how is carbon removed from the environment

A

photosynthesis, mineral formation, dissolution in oceans, trapped in fossil fuels

57
Q

how is carbon added to the environment

A

respiration, fossil fuel burning, volcanic activity

58
Q

reservoirs of inorganic carbon

A
  1. atmosphere
  2. oceans
  3. earth’s crust (limestone is largest reservoir)
59
Q

bogs

A

wetlands composed of acidified peat

60
Q

peat

A

slowly decomposing plant matter produced by low oxygen levels

61
Q

how is peat formed?

A

peat forms when partly decayed vegetation accumulates with flooding, preventing oxygen from reaching soil and resulting in anaerobic and acidic conditions

62
Q

why is decomposition so slow in bogs?

A

lack of oxygen

63
Q

how is coal formed?

A

as peat deposits are overlaid with sediment, increasing pressure and temperature causes it to fossilize and become coal

64
Q

how is the formation of oil different from coal?

A

the process is the same, but oil is formed from decaying aquatic plants and animals

65
Q

describe how decomposition occurs in bogs

A

methanogenic bacteria decompose plant matter and produce methane as a byproduct. methane is then recycled by methanotrophic bacteria, which oxidize methane to carbon dioxide

66
Q

what 2 processes cycle oxygen in the atmosphere?

A

cellular respiration and photosynthesis

67
Q

what is nitrogen required in the production of?

A

proteins and nucleic acids

68
Q

in what form is nitrogen accessible to living organisms?

A

nitrogen gas is very stable and inert, so it must first be converted into nitrates to be accessible to plants

69
Q

nitrogen fixation

A

the process of atmospheric/dissolved nitrogen being converted to nitrate ions

70
Q

in what 2 ways does nitrogen fixation occur?

A
  1. lightning (nitrogen is reacted with oxygen in the atmosphere)
  2. nitrogen-fixing bacteria (decomposers break down nitrogen in dead remains/waste into chemicals like ammonia, which is converted into nitrites, then nitrates)
71
Q

denitrification

A

the process of nitrates being converted into nitrites and then nitrogen gas

72
Q

what is the main difference between nitrogen fixation and denifrication (in terms of oxygenation)?

A

nitrogen fixation requires oxygen, but denifrification works better in anaerobic conditions

73
Q

why can bogs only support a few plant types?

A

they lack useful nitrogen

74
Q

why may discoloration of plant leaves indicate nitrate deficiency?

A

chlorophyll is a protein that requires nitrates

75
Q

fertilizers

A

materials used to restore nutrients to plants by replenishing the soil with nutrients/sources for nitrates

76
Q

why are fertilizers necessary for crops?

A

harvesting of crops removes important nutrients from the soil

77
Q

list 2 negative effects of fertilizers.

A
  1. too much use can acidify soil by inrroducing high amounts of nitric acid
  2. runoff of fertilizers into lakes/ponds can cause eutrophication
78
Q

explain how eutrophication occurs.

A

fertilizer runoff introduces nutrients that cause algal blooms in lakes, which blocks sunlight from penetrating the water. this causes plants to die, depleting oxygen levels that kills off other aquatic organisms. decomposing bacteria decompose these dead organisms as well as the algae, using more oxygen in the process. this eventually leads to an anoxic environment that cannot support life

79
Q

how does conversion of nitrates into nitrites affect hemoglobin containing species?

A

nitrites attach to hemoglobin and reduce its ability to carry oxygen

80
Q

long-term phosphorus cycle

A

phosphorus exists in bedrock as phosohates, which are eroded from the rock and carried to rivers and oceans. they are absorbed by algae and plants. aquatic organisms feeding on these algae and plants use the phosphates themselves to make bones and shells, which eventually become rock through sedimentation

81
Q

short-term phosphorus cycle

A

phosphates takeb up by plants are absorbed into food chains and recycled by decomposers

82
Q

indicator species

A

species sensitive to small changes in ecosystems that can provide early warning that the balance in an ecosystem is being negatively affected

83
Q

give an example of an indicator species. why is this species effective?

A

amphibians - abundant and are part of 2 separate ecosystems during their lifespan (juvenile and adult stages)

84
Q

why does high biodiversity lead to greater stability?

A

ecosystems with high biodiversity allow for dynamic equilibrium such that when one species is lost/declining, other organisms can compensate for it without disrupting the balance

85
Q

monocultures

A

agricultural practice of growing the same crop over a large area

86
Q

name 2 types of baited poisons.

A
  • sodium cyanide
  • compound 1080
87
Q

what are the negative effects of pesticides?

A

they are often not species-specific, causing non-target species to be negatively affected. this can affect reproductive ability and embryo development

88
Q

biomagnification

A

increase in concentration of a substance with each subsequent trophic level

89
Q

ecotone

A

transition zone between bordering ecosystems

90
Q

what are the characteristics of an ecotone?

A

greater biodiversity and less fragility

bio 20 (1 decks)

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