Environmental Interactions

Question 1

What is an abiotic factor?

Answer 1

-Non-living environmental factors that can affect organism in ecosystem
-Abiotic Factors can affect a range of Species as each organism is adapted to certain environments

Question 2

What is a biotic factor?

Answer 2

-Interactions between living organisms
-Biotic Factors will affect all Species as they have the vulnerability of being food to Predators or being a host to diseases that can affect Population of Species

Question 3

Examples of abiotic factors

Answer 3

-Light intensity
-Temperature
-Moisture levels
-Soil pH and mineral content
-Wind intensity and direction
-CO2 levels for plants
-O2 levels for aquatic animals

Question 4

Examples of biotic factors

Answer 4

-New predators
-Availability for food
-Competition
-New pathogens

Question 5

Explain the transfer of substances and energy along a food chain

Answer 5

-Energy enters most ecosystems in the form of sunlight, where it is converted into chemical energy by producers via Photosynthesis

Question 5

Why is only 10% of energy transferred from one trophic level to the next?

Answer 5

-Egestion->Removal of feces
-Excretion-> removal of urea
-Respiration loss
-Selective eating
-Animals can’t digest cellulose

Question 6

State two ways in which the process of turning nitrogen in the air into nitrates can occur

Answer 6

-By the action of nitrogen fixing bacteria
-By the action of lighting

Question 7

The nitrogen cycle (nitrogen fixing bacteria)

Answer 7

1. Nitrogen-fixing bacteria in the soil and roots of legume plants absorb nitrogen and reduce it to
   make ammonia. NITROGEN FIXATION
2. The ammonia is converted to nitrites and nitrates by nitrifying bacteria. NITRIFICATION
3. Plant roots can only absorb the nitrates
   -combined with carbohydrates (from
   photosynthesis) to form amino acids which are then made into proteins, and nucleotides which are
   joined to make DNA and RNA.
4. Animals eat plants. They digest the proteins and DNA, absorbing the small soluble molecules
   (amino acids and nucleotides).
   -used by the animal to synthesise (make) new proteins and
   DNA (assimilation).

Question 8

The nitrogen cycle (decomposers)

Answer 8

5. When a plant or animal dies its tissues are decomposed by bacteria and fungi (saprotrophic
   feeding).
6. Molecules containing nitrogen such as proteins are broken down by the bacteria and fungi and
   ammonia is released into the soil.

Question 9

The nitrogen cycle (nitrifying bacteria)

Answer 9

• NITRIFYING BACTERIA convert ammonium compounds to nitrites, then to nitrates, which plants can absorb (NITRIFICATION)

Question 10

The nitrogen cycle (denitrifying bacteria)

Answer 10

7. Some nitrates are converted into N2 by Denitrifying bacteria. DENITRIFICATION