Lesson 2 - Biotic and Abiotic Factors

Question 1

Biotic Factors - meaning and factors in the rocky shore environment

Answer 1

Living factors that influence the distribution and behaviour of an organism (i.e. interactions with other organisms).

• Predation
• Competition

Question 2

Abiotic Factors - meaning and factors in the rocky shore environment

Answer 2

Non-living factors that influence the distribution and behaviour of an organism.

• Tides
• Aerial exposure (IMPORTANT)
• Wave action
• Salinity (saltiness of surrounding water)
• Temperature
• Oxygen content (amount of dissolved oxygen inside organisms/surrounding water)

Question 3

Predation - Exploitation Relationships

Answer 3

Where one organism exploits another by consuming it - predator eating prey.

Exploitation is the relationship between two different species where one species benefits while the other is harmed (i.e. one species benefits at the expense of the other).

Organisms that have an exploitation (feeding) relationship with another are most likely to be found in the same zones together.

Question 4

Competition

Answer 4

Where two organisms share the same resources (space, food, mates) and must compete for those resources. Ultimately the fitter one will win.

Organisms that have competitive relationships (i.e. both need the same resources—food space, etc.) are more likely to be found in different zones.

Question 5

Tides

Answer 5

We experience two high tides and two low tides every 24 hours. Every six hours the tide alternates between high and low.

High Tide Zone: high air exposure / rarely (not often) submerged in water - risk of desiccation

Mid Tide Zone: moderate air exposure / sometimes submerged in water

Low Tide Zone: less exposure to air / almost always submerged

Question 6

Aerial Exposure

Answer 6

This is the amount of time exposed to the air. There is an increased risk of desiccation (drying out) as aerial exposure time increases. Rocky shore organisms are marine.

Question 7

Wave Action

Answer 7

The movement of waves.

Question 8

Salinity

Answer 8

Salinity increases as you move farther away from the low water mark (low tide) because as soon as a tide pool is cut off from the ocean (i.e. no longer high tide) the sun begins to heat those tide pools, evaporating the water and drawing out the salinity/salt of the water. This increase in salinity can cause distress to organisms, therefore, organisms need to have adaptations to tolerate both the salty and hot conditions.