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ecology + ecosystems Flashcards

(90 cards)

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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
food web
represents the feeding relationships among all the organisms in an ecosystem
26
trophic level
category of living things defined by how it gains its energy
27
3 types of trophic levels
producers, consumers, decomposers
28
first trophic level
producer
29
second trophic level
primary consumer
30
what happens to the amount of energy available as you move up the food chain?
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
31
10% rule
only 10% of the energy becomes available to the next trophic level
32
thermodynamics
the study of energy transformations
33
first law of thermodynamics
conservation of energy - energy cannot be created or destroyed, but it can be transferred from one form to another
34
second law of thermodynamics
entropy - some energy is transferred into an unusable form (thermal energy) when it is transferred. this energy is lost from the system
35
ecological pyramid
a representation of energy flow in food chains and webs
36
biomass
the total dry mass of all the living material in an ecosystem
37
what 2 consequences does the loss of energy with trophic levels create for an ecosystem?
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
name the 3 ecological pyramids
- pyramid of numbers - pyramid of biomass - pyramid of energy
39
pyramid of numbers
outlines the number of organisms at each trophic level, based on #/unit area
40
pyramid of biomass
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
pyramid of energy
outlines the amount of energy available at each trophic level, given in calories/joules. measured in energy per unit area per unit time
42
are each of the pyramids always in a pyramid shape?
pyramids of energy always taken on a pyramid shape, whereas the others may vary - although this shape is most common
43
chemosynthesis
the process of non-photosynthetic organisms converting inorganic chemicals to organic compounds without solar energy
44
chemoautotrophs
perform chemosynthesis to make nutrients using only water, carbon dioxide and an energy source
45
where is the energy used by chemoautotrophs found?
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
environmental vegetarianism
the belief that production of meat and animal products is unsustainable due to inefficient energy consumption
47
what 2 processes are involved in the cycling of matter?
1. digestion (complex organic molecules are broken down in the body) 2. decay (decomposers and detritivores break down organic matter in waste)
48
name the 5 biogeochemical cycles
hydrological (water), carbon, oxygen, nitrogen, phosphorus
49
list the steps of the water cycle
precipitation, collection (& percolation), evaporation, condensation
50
percolation
the downward movement of water through soil due to gravity
51
water table
region below the ground saturated with water
52
leaching
the loss of dissolved organic matter and nutrients from the soil through percolation of water
53
how do plants help counteract leaching?
they have deep, branching roots which return materials to the surface
54
acid rain
precipitation of acidified water caused by emissions of sulfur dioxide and nitrous oxides
55
carbon flux
the flow of carbon between carbon pools (net difference between removal and addition)
56
how is carbon removed from the environment
photosynthesis, mineral formation, dissolution in oceans, trapped in fossil fuels
57
how is carbon added to the environment
respiration, fossil fuel burning, volcanic activity
58
reservoirs of inorganic carbon
1. atmosphere 2. oceans 3. earth's crust (limestone is largest reservoir)
59
bogs
wetlands composed of acidified peat
60
peat
slowly decomposing plant matter produced by low oxygen levels
61
how is peat formed?
peat forms when partly decayed vegetation accumulates with flooding, preventing oxygen from reaching soil and resulting in anaerobic and acidic conditions
62
why is decomposition so slow in bogs?
lack of oxygen
63
how is coal formed?
as peat deposits are overlaid with sediment, increasing pressure and temperature causes it to fossilize and become coal
64
how is the formation of oil different from coal?
the process is the same, but oil is formed from decaying aquatic plants and animals
65
describe how decomposition occurs in bogs
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
what 2 processes cycle oxygen in the atmosphere?
cellular respiration and photosynthesis
67
what is nitrogen required in the production of?
proteins and nucleic acids
68
in what form is nitrogen accessible to living organisms?
nitrogen gas is very stable and inert, so it must first be converted into nitrates to be accessible to plants
69
nitrogen fixation
the process of atmospheric/dissolved nitrogen being converted to nitrate ions
70
in what 2 ways does nitrogen fixation occur?
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
denitrification
the process of nitrates being converted into nitrites and then nitrogen gas
72
what is the main difference between nitrogen fixation and denifrication (in terms of oxygenation)?
nitrogen fixation requires oxygen, but denifrification works better in anaerobic conditions
73
why can bogs only support a few plant types?
they lack useful nitrogen
74
why may discoloration of plant leaves indicate nitrate deficiency?
chlorophyll is a protein that requires nitrates
75
fertilizers
materials used to restore nutrients to plants by replenishing the soil with nutrients/sources for nitrates
76
why are fertilizers necessary for crops?
harvesting of crops removes important nutrients from the soil
77
list 2 negative effects of fertilizers.
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
explain how eutrophication occurs.
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
how does conversion of nitrates into nitrites affect hemoglobin containing species?
nitrites attach to hemoglobin and reduce its ability to carry oxygen
80
long-term phosphorus cycle
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
short-term phosphorus cycle
phosphates takeb up by plants are absorbed into food chains and recycled by decomposers
82
indicator species
species sensitive to small changes in ecosystems that can provide early warning that the balance in an ecosystem is being negatively affected
83
give an example of an indicator species. why is this species effective?
amphibians - abundant and are part of 2 separate ecosystems during their lifespan (juvenile and adult stages)
84
why does high biodiversity lead to greater stability?
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
monocultures
agricultural practice of growing the same crop over a large area
86
name 2 types of baited poisons.
- sodium cyanide - compound 1080
87
what are the negative effects of pesticides?
they are often not species-specific, causing non-target species to be negatively affected. this can affect reproductive ability and embryo development
88
biomagnification
increase in concentration of a substance with each subsequent trophic level
89
ecotone
transition zone between bordering ecosystems
90
what are the characteristics of an ecotone?
greater biodiversity and less fragility

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