Recycling materials in the ecosystem

Question 1

name the two types of decomposer

Answer 1

bacteria and fungi

Question 2

what is this form of nutrition (fungi feeding)

Answer 2

saprotrophic

Question 3

why does decomposition result in carbon dioxide being released

Answer 3

due to the bacteria and fungi respiring, thus resulting in the release of carbon dioxide

Question 4

why is nitrogen so important

Answer 4

DNA and proteins

Question 5

what is nitrogen fixation

Answer 5

Atmospheric nitrogen gas is converted into nitrogen-containing compounds
This biological nitrogen fixation is carried out by nitrogen-fixing bacteria such as Rhizobium
The bacteria convert nitrogen into ammonia, which forms ammonium ions (in solution) that can then be used by plants
These nitrogen-fixing bacteria are found inside the root nodules (small growths on the roots) of leguminous plants such as peas, beans and clover
The bacteria have a symbiotic (mutually beneficial) relationship with these plants - the bacteria provide the plants with nitrogen-containing compounds and the plants provide the bacteria with organic compounds such as carbohydrates

Question 6

what is ammonification

Answer 6

Nitrogen compounds in waste products (e.g. urine and faeces) and dead organisms are converted into ammonia by saprobionts (a type of decomposer including some fungi and bacteria)
This ammonia forms ammonium ions in the soil

Question 7

what is nitrification

Answer 7

The ammonium ions in the soil are converted by nitrifying bacteria into nitrogen compounds that can be used by plants, known as nitrates
Initially, nitrifying bacteria such as Nitrosomonas convert ammonium ions into nitrites
Different nitrifying bacteria such as Nitrobacter then convert these nitrites into nitrates

Question 8

what is denitrification

Answer 8

Denitrifying bacteria use nitrates in the soil during respiration
This process produces nitrogen gas, which returns to the atmosphere
This process occurs in anaerobic conditions (when there is little or no oxygen available, such as in waterlogged soil)

Question 9

what is the purpose of leghaemoglobin

Answer 9

to absorb oxygen

Question 10

what does nitrogen reductase do

Answer 10

reduces nitrogen, by adding hydrogen and producing ammonia

Question 11

what are the bacteria involved in nitrogen fixation

Answer 11

• Azotobacter
• Rhizobium.

Question 12

what are the bacteria involved in nitrification

Answer 12

• Nitrosomonas
• nitorbacter

Question 13

what are the bacteria involved in denitrification

Answer 13

• anaerobic denitrifying bacteria

Question 14

state 3 differences between the carbon and nitrogen cycle

Answer 14

• different bacterial species
• lightening lightening versus combustion
• photosynthesis only involved in combustion

Question 15

state 3 similarities between the carbon and nitrogen cycle.

Answer 15

• decomposition (decomposers)
• plants and animals involved
• eating and egestion/ excretion involved
• mixture of biological and non - biological involvement
• how nutrients are recycled around ecosystems
• respiration

Question 16

name a compound that can be classified as organic nitrogen

Answer 16

amino acids

Question 17

name a compound that can be classified as organic nitrogen

Answer 17

amino acids

Question 18

name one of the types of bacteria, involved in the process of turning organic nitrogen to inorganic nitrogen

Answer 18

nitrifying bacteria

Question 19

name one of the types of bacteria, associated with turning nitrates, into nitrogen gas

Answer 19

denitrifying bacteria

Question 20

what is succession

Answer 20

succession, is a directional change in the composition of species in a community, that occupy a given area throughout time.

Question 21

what causes succession ( state 2 things)

Answer 21

• changes, in the community, cause changes in the physical environment
• this, causes another community, to become established and replace the former

Question 22

what is the pioneer community

Answer 22

the first organism to colonise an area.

Question 23

what is the climax community

Answer 23

the final stable community after succession

Question 24

what is secondary succession

Answer 24

the recolonization, of an area, after an earlier community has been removed or destroyed

Question 25

what is primary succession

Answer 25

ecological community develops in the absence of soil (i.e. from bare rock)

Question 26

what is deflected succession

Answer 26

occurs, when a community remains stable, due to human activity, preventing further succession for example regular mowing or grazing of livestock

Question 27

what plagioclimax

Answer 27

climax community, after deflected succession

Question 28

what is the goal of the first colonizers

Answer 28

to make soil

Question 29

what do we call the organism that first colonize

Answer 29

pioneer species

Question 30

what is the main way that we can tell if an area is in a later stage of succession

Answer 30

if it has a high diversity

Question 31

why is a later stage able to have greater diversity

Answer 31

due to being made of thousands of organism communities.

Question 32

can we always predict the route succession is going to take?

Answer 32

no it’s random

Question 33

outline the process of succession occurring on Surtsey island

Answer 33

• (1)after new rock has formed, lichens are established as the pioneer community
• (2)these organism, cause erosion of rock and provide dead material, which when decomposed, helps form soil
• (3)larger plants, like moss can then grow, and these types of species, replace the pioneer community
• (4)these plants, add further nutrients, moisture etc, to the soil and create shelter, This causes other species, to now occupy the area (shrubs etc) these outcompete the moss.
• (5) this process, continues, until a climax community is reached (often woodland in temperate areas)

Question 34

outline the process of succession occurring on sand dunes

Answer 34

• beach - pioneer species, can be found here.
• mini dunes - as wind blows, sand builds up around the base of pioneer plants, inin dunes from. As dune increase in size, stabilising plants, like couch grass, helping to establish the dunes.
• young yellow dunes - increased stability, and more nutrients, allows marram grass, to grow. This collects sand well increasing dunes further in size.
• old grey dunes - more mature dunes, allow leguminous plants, to grow. these have resident bacteria, to convert nitrogen gas to nitrates, further increasing the nutrients in the dune, allowing other plants to grow.

Question 35

why do sand dunes, get darker as you go away from the sea

Answer 35

more soil and nutrients in the sand, the further inland that you come.

Question 36

why is a later stage of succession able to greater diversity

Answer 36

due to being made of thousands of organisms and communities.

Question 37

what level of disturbance, results in the greatest developmental change?

Answer 37

intermediate

Question 38

why do people, burn forest regularly

Answer 38

to avoid extremely catastrophic events, that would completely wipe out the diversity of an area.