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Bio Module 6 > Ecosystem 6.5 > Flashcards

Ecosystem 6.5 Flashcards

1
Q

What is an ecosystem?

A

Comminity of plants, animals and smaller organisms that live, feed, reprodce and interact in the same area or evironment

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2
Q

What does it mean when ecosystems are dynamic?

A

They are constantly changing

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3
Q

What is a biotic factor and what are some examples?

A
  • all living factors of an ecosystem
  • predators
  • feeding
  • competition
  • parasitism
  • mutiualism
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4
Q

What is an abiotic factor and what are some examples?

A
  • all non livig factors of an ecosystem
  • light intensity
  • pH
  • nutrients
  • temperature
  • water supply
  • O2 / CO2 conc.
  • organic ion availibility
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5
Q

What is biomass?

A

The total mass of organic material, measured in a specific area over a set time period (can be calculated in terms of dry mass)

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6
Q

What is a producer?

A

Photosynthetic organisms at the start of the food chain that manufacture biomass for al living things

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7
Q

What is a consumer?

A

Organisms that feed of other organisms to obtain energy

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8
Q

What is a decomposer?

A

Organisms that release enzymes which catalyse the breakdow of dead plant and animal material into simpler organic matter

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9
Q

What is a trophic level?

A

The level at which an organism feeds in a food chain

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10
Q

What do food chains show?

A

How energy is transferred from one organism to another

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11
Q

Why is energy lost between trophic levels?

A
  • plants can’t use all light energy that reaches theirs leaves
  • some plant parts of food are not eaten
  • some parts of animals are indigestable
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12
Q

How do you calculate ecological efficiency?

A

Biomass at higher trophic levels / Biomass of lower trophic levels X 100

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13
Q

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

A
  • providing artificial light in greenhouses on overcast days
  • optimising planting distances between crops
  • irrigation to maximise growth in dry weather
  • use of fertilisers
  • selective breeding for fast growth
  • use of fungicides/pesticides
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14
Q

What is a pyramid of numbers?

A

Where each bar in the pyramid is proportional to the number of individuals

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15
Q

What is a pyramid of biomass?

A

Where each bar is proprtional to the dry mass

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16
Q

What is the efficiency of biomass transfers between trophic levels?

A

10% of biomass is transferred between trophic levels in a healthy ecosystem

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17
Q

What is primary productivity?

A

The rate at which energy is converted to organic substances by potosynthesis

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18
Q

What is secondary productivity?

A

The amount of chemical energy and biomass produced by heterotrophic organisms at a given loctaion and at a specific time

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19
Q

What is net primary productivity?

A

The chemical energy stored in plant biomass after respiratory losses to the environment have been accounted for

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20
Q

What is gross primary productivity?

A

The rate at which plants conver light energy into chmical energy through photosynthesis

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21
Q

How do you calculate net primary productivity?

A

Gross primary productivity - Respiration losses

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22
Q

What is productivity?

A

The rate of production of new biomass by producers

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23
Q

How do you increase primary productivity?

A

By manipulating environmental factors
- increasing light intensity (light banks)
- irrigating crops (drought resistant crop)
- growing plants in greenhouses (warmer temperatures)
- crop rotation prevents lack of availability of nutrients
- pesticides
- fungicide

24
Q

How do you increase secondary productivity?

A
  • harvesting animals just before adulthood
  • selective breeding for animals with faster growth rates, increased egg production and increased milk production
  • animals treated by antibiotics
  • zero grazing (prevent animals from moving)
25
What does it mean when bacteria and fungi feed saprotrophically?
They release digestive enzymes, so the food is digested externally, and then they absorbe the pre-digested food
26
What is nitrogen fixing?
Converting nitrogen in the air into ammonium or ions - From N2 - NH4+
27
What microoganisms do nitrogen fixing?
- Azotobacter - Rhizobium
28
How else can nitrogen be converted into ammonium ions?
Through legume plants
29
What is nitrification?
Converting ammonium ions into nitrate and nitrite ions by oxidising them - From NH4+ - To NO3- / NO2-
30
What microorganisms (chemoautotrophs) do nitrification?
- Nitrosomonas - Nitrobacter
31
What is denitrification?
Converting nitrate ions back into gaseous nitrogen or nitrogen oxide - From NO3- - To N2 / N2O
32
What microogranisms do denitrification?
Bacteria
33
Why is nitrogen important?
It is needed to make amino acids and protein
34
What happens during the nitrogen cycle?
- nitrogen in the air is converted into ammonium ions by azobacter - nitrogen can also be converted into ammonium ions by rhizobium which are bacteria found on legume plants - ammonium ions are converted to nitrite ions by nitrosomonas - nitrite ions are converted to nitrate ions by nitrobacter - nitrate ions are taken up by plants - the plants are then eaten by heterotrophs - heterotrophs then die and decompose releasing ammonium ions into the soil - nitrate ions are converted into gaseous nitrogen by bacteria
35
What is the importance of the carbon cycle?
It regulates the earth's temperature, makes up the food that sustains us, and provides energy that fuels our global economy
36
How is carbon stored?
- atmosphere (CO2) - sedimentary rocks - fossil fuels like (coal, oil, and gas) - soil and other organic matter - vegetation (cellulose) - dissolved in the oceans (as CO2)
37
What does the carbon cycle show?
It shows how atoms of carbon can exist within different compounds at different times and be recycled between living organisms and the environment
38
What are the stages in the carbon cycle?
- photosynthesis - sedimentation - respiration - feeding - decay and decomposition - burning fossil fuels
39
How does photosynthesis link to the carbon cycle?
- autotrophs use the energy of sunlight to 'fix' carbon dioxide, turning the carbon into sugars - this removes carbon from the atmosphere - terrestrial plants use CO2 directly from the air - aquatic organisms use CO2 dissloved in water
40
How does sedimentation link to the carbon cycle?
- plants that die are not fully decomposed and form layers of sediment that accumulates, locking carbon into the ground - sediment is a store of energy and can form fossil fuels like peat and coal - aquatic organisms also form sediments and fossil fuelslike oil and gas
41
How does respiration link to the carbon cycle?
- respiration puts CO2 into the atmosphere - CO2 is released in the link reaction and krebs cycle - anaerobic respiration also releases CO2 via fermentation by yeast and bacteria
42
How does feeding link to the carbon cycle?
- carbon is passed from autotroph to heterotroph during feeding - carbon is also passed from primary consumer to secondary consumer
43
How do decay and decomposistion link to the carbon cycle?
- dead organisms are fed upon and decayed by saprophytes which releases carbon into the surroundings and supplys carbon to the saprophytes - waste matter is used by decaying saprobionts which can release CO2 back into the air
44
How does burning fossil fuels link to the carbon cycle?
- burning fossil fuels releases CO2 into the atmosphere - it is released faster than it can be absorbed by plants and aquatic producers - warmer temperatures means less CO2 can be dissolved in oceans
45
What is a population?
Number of organisms / a single species
46
What is succession?
A change in a habitat causing a change in the make-up of a community
47
What is primary succession?
The process that occurs when newly formed or newly exposed land is gradually colonised by an increasing number of species
48
What is secondary succession?
When a previously occupied area is colonised again following a disturbance that kills much or all of its community
49
what are the stages of primary succession from a pioneer species to climax community?
- seeds and spores that are carried by the wind land on the exposed rock and begin to grow - first to colonise the new land are mosses and lichens, pioneering species - they break apart the top surface of the rock and die and decompose leaving dead organic matter which forms a basic soil - Seeds of small plants and grasses land on this basic soil and begin to grow - the small plants die and decompose so the new soil is deeper and more nutrient-rich and the roots form a network to hold the soil and prevent it being washed away - larger plants and shrubs that require deeper, more nutrient-rich soil, can now begin to grow - the soil is sufficiently deep, contains enough nutrients and can hold enough water to support the growth of large trees - the final species to colonise the new land become the dominant species of the complex ecosystem - final community formed, containing all the different plant and animal species that have now colonised the new land, is known as the climax community
50
what are the changes in environment in succession caused by?
- at each stage there are certain species that gradually change the environment so it is more suitable for other species that have not yet colonised the new land - the new colonising species then change the environment in such a way that it becomes less suitable for the previous species
51
What is a pioneer community?
Species of plant that can survive in hostile environments and colonise bare rocks or sand
52
What is a climax community?
The stable community at the end of succession
53
What is deflected succession?
When human activities prevent or interrupt the process of succession
54
How can you prevent succession?
- regular mowing of grass - grazing activities of livestock - managed burning
55
How do you manage succession?
- through conservation which involves the protection and management of ecosystems - preventing an area from reaching its climax community can sometimes be a good thing because ecosystems at the intermediate stages of succession (small plants, grasses or shrubs) are present, often hold a diversity of plant species that would no longer exist if the climax community was reached - diverse plant species provide food and habitat for a high diversity of animal species
56
How is the distribution and abundance of organisms in an ecosystem measured?
Using sampling methods
57
What sampling and recording methods are used to determin distribution and abundance of organisms in ecosystems?
- random - systematic - quadrats - transects - mark-release-recapture

Bio Module 6 (6 decks)

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