Maintaining a balance in the environment

Question 1

What common misconception do people have about micro-organisms?

Answer 1

They believe that they are all harmful however most micro-organisms are benign (harmless) or extremely useful, and to destroy them would be to destroy ourselves. It is only now that their importance in the stable functioning of ecosystems has been fully recognised.

Question 2

What is the importance of micro-organism diversity?

Answer 2

It gives the environment a better chance to survive a change or threat to it such as drought or man-made habitat degradation.

Question 3

What will happen if an ecological process such as nutrient cycling or decomposition of organic matter is damaged or destroyed?

Answer 3

Biodiversity will allow alternative pathways for that particular process to occur. The ecosystem can therefore continue functioning healthily at its normal level.

Question 4

The web of life depends on this vast network of ___ communities with their huge _____. Environmental ___ is ensured because they are responsible for they very wide of vital ____ in the environment.

Answer 4

Unseen
Biodiversity
Stability
Functions

Question 5

What are plant-degraders?

Answer 5

Cellulose-degrading fungi or bacteria that clean up dead plants in the environment.

Question 6

____ are recycled in the environment, unlike energy.

Answer 6

Nutrients

Question 7

What would happen to a dead plant or animals’ nutrients if it were not for decomposers?

Answer 7

It would remain in its tissues.

Question 8

___ e.g. ants and ___ e.g. earthworms feed on the dead organisms or litter, but they leave behind a considerable amount of ___ organic matter.

Answer 8

Scavengers
Detritivores
Unused

Question 9

What do decomposer-microorganism or micro-regulators do to the organic matter left behind by scavengers and detritivores?

Answer 9

The saprotrophic bacteria and fungi breakdown the remaining organic matter into carbon dioxide and nutrients.

Question 10

What are the micro-regulators in marine ecosystems?

Answer 10

Protozoan protists

Question 11

What happens to the nutrients which is produced post decomposition?

Answer 11

The nutrients e.g. nitrates and phosphates are absorbed by terrestrial plants and algae in order for them to grow and survive.

Question 12

What role do micro-organisms play in terms of atmospheric concentration?

Answer 12

They play a vital role in keeping the level of oxygen at 21%.

Question 13

Why are blue-green algae (cyanobacteria) and phytoplankton vital?

Answer 13

They are vital oxygen generators. It Is estimated that they replace about 50% of all oxygen used. It will help replace some of the oxygen removed from the atmosphere during respiration.

Question 14

What are the functions of microorganisms in the environment? (5)

Answer 14

1. ) Plant degraders
2. ) Micro-regulators of nutrients
3. ) Regeneration of oxygen
4. ) Nitrogen transformers
5. ) Biological control agents

Question 15

What are nitrifying-bacteria?

Answer 15

They change nitrogen into a usable form, i.e. nitrates.

Question 16

Micro-organisms can act as natural enemies of __, ___ and weeds. This helps keep the environment ___ and balanced.

Answer 16

Pests
Pathogens
Healthy

Question 17

What is symbiosis?

Answer 17

It is a close association between different species.

Question 18

What are the 3 types of symbiosis?

Answer 18

• Mutualism
• Parasitism
• Commensalism

Question 19

What is mutualism?

Answer 19

Symbiosis which is beneficial to both organisms involved.

Question 20

What is parasitism?

Answer 20

Symbiosis where one benefits and the other is harmed.

Question 21

What is commensalism?

Answer 21

Symbiosis where neither are harmed but one benefits.

Question 22

____ strains of E. Coli a bacterium found in the colon as part of the normal gut ____.

Answer 22

Harmless

Flora

Question 23

What is human flora?

Answer 23

Micro-organisms (bacteria and fungi) that inhabit the human body. Some are useful for the human host, while the majority have no beneficial or harmful effect.

Question 24

Describe the mutualistic relationship between E. coli and humans.

Answer 24

• Bacteria benefit by obtaining glucose and other nutrients from the undigested food remains in the colon
• Humans benefit by gaining vitamin K2 and protection against the growth of pathogenic bacteria within the gut

Question 25

What is the importance of Vitamin K?

Answer 25

It is needed to form the enzyme thrombin; a key enzyme involved in the blood clotting process.

Question 26

Describe the mutualistic relationship between nitrogen fixing bacteria and plants.

Answer 26

-Rhizobium benefits by gaining glucose and other nutrients as well as favourable habitat from the plant
-The plant benefits by gaining ammonia, produced by the bacterium from gaseous nitrogen and hydrogen. The ammonia is used to make amino acids.
Thus the nitrogen from the atmosphere is fixed into organic material which results in the growth of the plant

Question 27

Why is nitrogen-fixation necessary?

Answer 27

It is necessary to convert atmospheric nitrogen into forms that living organisms can use. Some fixation occurs in lightning strikes, but most fixation is done by symbiotic and free-living bacteria.

Question 28

Where do rhizobium live?

Answer 28

In the roots nodules of legumes (such peas or beans).

Question 29

What are Mycorrhizal fungi?

Answer 29

These fungi infect the roots and send out root-like structures called hyphae which extend far out from the plant’s roots.

Question 30

Approximately ___-__% of all plants have mycorrhizae.

Answer 30

70-80%

Question 31

Describe the mutualistic relationship between Mycorrhizal fungi and plant roots.

Answer 31

• The fungi provides the plant with an increased absorptive surface area which will improve the nutrient uptake by plants
• Protection against pests and diseases thereby improving their health
• In return the plant provides the fungus with glucose