Ecosystems Flashcards

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1
Q

How does temperature affect ecosystems?

A
  • Affects enzymes controlling metabolic reactions
  • Warmer temperatures may allow plants and ectothermic animals to develop faster
  • Changes in temperature can trigger migration and/or hibernation in some animal species
  • Changes in temp can trigger leaf fall or dormancy in some plants
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2
Q

What are edaphic factors?

A
  • Relate to soil type
  • Different soil types have different particle size, which affect the organisms that are able to survive in them
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3
Q

How can human activities like agriculture manipulate the transfer of biomass through ecosystems?

A
  • Creates simple food chains by reducing the number of trophic levels
  • They ensure that as much of the energy as possible is transferred into biomass that can be eaten by humans
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4
Q

What is ecological efficiency and how can it be calculated?

A
  • The percentage efficiency at which biomass or energy is transferred from one trophic level to the next
  • energy or biomass available after transfer / energy or biomass available before transfer x 100
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5
Q

What are the basic trophic levels in a food chain?

A
  • Producers - make their own food
  • Primary consumers - consume producers
  • Secondary consumers - consume primary
  • Tertiary consumers - consume secondary
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6
Q

What do decomposers do?

A
  • Break down complex materials in dead organisms into simpler ones
  • This releases nutrients back into the ecosystem
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7
Q

How is net and gross primary production calculated?

A

NPP = GPP - respiratory losses
- GPP is the quantity of solar energy that plants convert to organic matter and store as chemical energy

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8
Q

What are some ways energy can be lost from biomass?

A
  • Some energy is lost through photosynthetic reactions
  • Not all biomass is digestible by consumers
  • Some energy lost to the environment as heat during movement or respiration
  • Some energy lost in excretory materials like urine and faeces
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9
Q

What is ammonification?

A

The conversion of organic nitrogen-containing compounds into substances like ammonia by decomposers

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10
Q

What is nitrification?

A
  • Conversion of ammonia or ammonium ions into nitrites (by nitrosomas) and then nitrates (by nitrobacter)
  • Two stage oxidation process
  • Nitrate ions can then be absorbed by plants
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11
Q

What is nitrogen fixation?

A
  • Nitrogen gas is converted into nitrogen containing compounds like ammonia
  • By rhizobium and azotobacter
  • Bacteria in the soil perform this, then convert the ammonia into amino acids
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12
Q

What is detrification?

A
  • Where denitrifying bacteria convert soil nitrates into gaseous nitrogen
  • Anaerobic process
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13
Q

What happens if organic matter accumulates in regions without decomposers?

A

The carbon they contain may become trapped, forming fossil fuels over millions of years

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14
Q

How does global warming affect the levels of carbon dioxide containing compounds in the ocean and atmosphere?

A
  • Global warming reduces the amount of carbon dioxide that can dissolve in oceans, as at higher temps less gas can dissolve in water
  • So more carbon dioxide is released into the atmosphere
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15
Q

What is a pioneer community and some of they key characteristics of a pioneer species?

A
  • First stage of succession in which pioneer species colonise an inhospitable environment and make it more suitable for other species
    Pioneer species can usually -
  • reproduce asexually
  • germinate rapidly
  • photosynthesise
  • fix nitrogen from the atmosphere
  • tolerate extreme conditions
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16
Q

What is a climax community?

A
  • A stable ecosystem with a balanced equilibrium of species
  • Characterised by a smaller number of dominant plant and animal species that are rarely replaced by new species
17
Q

What is deflected succession, and what may lead to it?

A
  • When human activities stop the natural flow of succession, preventing the ecosystem from reaching a climax community
    Due to
  • grazing and trampling of vegetation
  • removing existing vegetation to plant crops
  • burning for forest clearance