Physical and Abiotic Factors that affect an Ecosystem

Question 1

What are the physical/abiotic factors that affect the ecosystem?

Answer 1

1. Climate - light, temperature, rainfall, humidity
2. Physiographic - hilly or at high altitude.
3. Edaphic - soil and its properties
4. Aquatic - pH, oxygen concentration and salinity.

Question 2

What does light do in the ecosystem?

Answer 2

It provides the energy used by plants in photosynthesis. Animals depend on these plants for food.

Intensity
Wave length/colour
Duration

Question 2

What is light intensity?

Answer 2

This is how bright the light is. As the intensity increases, so does the rate of photsynthesis.
Eg. hibiscus and yams (tropical crops) prefer bright light.
Ferns and orchids prefer shade.

Woodlice prefer shade and soil-living organisms.

Question 3

How do plants on the forest floor adapt to having low levels of light?

Answer 3

1. They have broad thin leaves with a large surface area to volume ratio.
2. They have lots of chlorophyll or chloroplasts.

Question 4

What is wavelength?

Answer 4

This is the colour of the light. As it penetrates the water, it is absorbed and scattered by water molecules and suspended particles.
If the water is too deep then light cannot go beyond a certain depth.
- No plants (photosynthesis), no animals
Some plants are specially adapted for this.

Question 5

What is light duration?

Answer 5

Day length or the photoperiod is the amount of time that light is present throughout the day. Some flowering plants only bloom when the photoperiod is short. (Christmas - poinsettia).
Some prefer longer days - (poinciana).

Question 6

What is Water?

Answer 6

Water forms 70% of the living protoplasm, provides a medium for metabolic activities and a habitat. The more water, the more plants and animals that will be present.

• Availability
• Acidity
• Oxygen concentration

Question 7

What is water availability?

Answer 7

The extent to which water is available. Many terrestrial plants and animals are unable to withstand long periods of time without water. These organisms must live in humid and high rainfall places.

Other plants (aloe vera) that live in dry places are well adapted to live there.

Question 8

The other factors of water.

Answer 8

The pH, salinity oxygen concentration, flow of water, depth and light penetration affect the distribution of organisms.
eg. Fast moving water has higher oxygen concentration than still water. (picking up oxygen as bubbles). There are more organisms living here which must be able to hold their positions.

Light penetration depends on the presence of suspended matter and the depth of the water. The more light, the more plants (photosynthesis) and animals.